Search

Rosiglitazone is an activator of nuclear peroxisome proliferator-activated (PPAR) receptor gamma used in the treatment of type 2 diabetes mellitus. The elimination of rosiglitazone occurs mainly via metabolism, with major contribution by enzyme cytochrome P450 (CYP) 2C8. Primary routes of rosiglitazone metabolism are N-demethylation and hydroxylation. Modulation of CYP2C8 activity by co-administered drugs lead to prominent changes in the exposure of rosiglitazone and its metabolites. Here, we attempt to develop mechanistic parent-metabolite physiologically based pharmacokinetic (PBPK) model for rosiglitazone. Our goal is to predict potential drug-drug interaction (DDI) and consequent changes in metabolite N-desmethyl rosiglitazone exposure. The PBPK modeling was performed in the PKSim® software using clinical pharmacokinetics data from literature. The contribution to N-desmethyl rosiglitazone formation by CYP2C8 was delineated using vitro metabolite formation rates from recombinant enzyme system. Developed model was verified for prediction of rosiglitazone DDI potential and its metabolite exposure based on observed clinical DDI studies. Developed model exhibited good predictive performance both for rosiglitazone and N-desmethyl rosiglitazone respectively, evaluated based on commonly acceptable criteria. In conclusion, developed model helps with prediction of CYP2C8 DDI using rosiglitazone as a substrate, as well as changes in metabolite exposure. In vitro data for metabolite formation can be successfully utilized to translate to in vivo conditions., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest., (Copyright © 2024 The Japanese Society for the Study of Xenobiotics. Published by Elsevier Ltd. All rights reserved.)

Leriglitazone is a unique peroxisome proliferator-activated receptor-gamma (PPARγ) agonist that crosses the blood-brain barrier in humans and clinical trials have shown evidence of efficacy in neurodegenerative diseases. At clinical doses which are well-tolerated, leriglitazone reaches the target central nervous system (CNS) concentrations that are needed for PPARγ engagement and efficacy; PPARγ engagement is also supported by clinical and anti-inflammatory biomarker changes in the Cerebrospinal fluid in the CNS. Plasma pharmacokinetics (PK) of leriglitazone were determined in a phase 1 study in male healthy volunteers comprising a single ascending dose (SAD) and a multiple ascending dose (MAD) at oral doses of 30, 90, and 270 mg and 135 and 270 mg, respectively. Leriglitazone was rapidly absorbed with no food effect on overall exposure and showed a linear PK profile with dose-exposure correlation. A physiologically based pharmacokinetic (PBPK) model was developed for leriglitazone based on phase 1 data (SAD part) and incorporated CYP3A4 (f mCYP3A4  = 24%) and CYP2C8-mediated (f mCYP2C8  = 45%) metabolism, as well as biliary clearance (f eBIL  = 19.5%) derived from in vitro data, and was verified by comparing the observed versus predicted concentration-time profiles from the MAD part. The PBPK model was prospectively applied to predict the starting pediatric doses and was preliminarily verified with data from five pediatric patients., (© 2024 Minoryx Therapeutics S.L. CPT: Pharmacometrics & Systems Pharmacology published by Wiley Periodicals LLC on behalf of American Society for Clinical Pharmacology and Therapeutics.)

In this open-label, single-dose, parallel-group study, we compared the pharmacokinetic profile and safety of lobeglitazone, a thiazolidinedione acting as an agonist for peroxisome proliferator-activated receptors, in patients with hepatic impairment (HI) and healthy matched controls for age, sex, and body weight. After a single oral dose of lobeglitazone (0.5 mg), the lobeglitazone (parent drug) and M7 (major metabolite) plasma concentrations and pharmacokinetic parameters were analyzed and compared between the HI patient groups and healthy matched control groups. The geometric mean ratio (GMR; 90% confidence interval [CI]) for maximum concentration (C max ) and area under the plasma concentration-time curve from time 0 extrapolated to infinity (AUC inf ) of lobeglitazone was 1.06 (0.90-1.24) and 1.07 (0.82-1.40), respectively, for mild HI vs control A. The GMR (90%CI) of C max and AUC inf was 0.70 (0.56-0.88) and 1.00 (0.72-1.37), respectively, for moderate HI vs control B. For M7, the GMR (90%CI) of C max and AUC inf was 1.09 (0.75-1.57) and 1.18 (0.71-1.97), respectively, for mild HI vs control A and 1.50 (0.95-2.38) and 1.79 (1.06-3.04), respectively, for moderate HI vs control B. Notable adverse events or tolerability issues were not observed. Lobeglitazone may be safely used in patients with mild or moderate HI without dose adjustment., (© 2022, The American College of Clinical Pharmacology.)

In search of dually active PPAR-modulators/aldose reductase (ALR2) inhibitors, 16 benzylidene thiazolidinedione derivatives, previously reported as partial PPARγ agonists, together with additional 18 structural congeners, were studied for aldose reductase inhibitory activity. While no compounds had dual property, our efforts led to the identification of promising inhibitors of ALR2. Eight compounds (11, 15-16, 20-24, 30) from the library of 33 compounds were identified as potent and selective inhibitors of ALR2. Compound 21 was the most effective and selective inhibitor with an IC 50 value of 0.95 ± 0.11 and 13.52 ± 0.81 μM against ALR2 and aldehyde reductase (ALR1) enzymes, respectively. Molecular docking and dynamics studies were performed to understand inhibitor-enzyme interactions at the molecular level that determine the potency and selectivity. Compound 21 was further subjected to in silico and in vitro studies to evaluate the pharmacokinetic profile. Being less acidic (pKa = 9.8), the compound might have a superior plasma membrane permeability and reach the cytosolic ALR2. This fact together with excellent drug-likeness criteria points to improved bioavailability compared to the clinically used compound Epalrestat. The designed compounds represent a novel group of non-carboxylate inhibitors of aldose reductase with an improved physicochemical profile., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Masson SAS. All rights reserved.)

Inhibition of the BCL6 BTB domain results in killing Diffuse Large B-cell Lymphoma (DLBL) cells, reducing the T-cell dependent germinal center (GC) reaction in mice, and reversing GC hyperplasia in nonhuman primates. The available BCL6 BTB-specific inhibitors are poorly water soluble, thus, limiting their absorption in vivo and our understanding of therapeutic strategy targeting GC. We synthesized a prodrug (AP-4-287) from a potent BCL6 BTB inhibitor (FX1) with improved aqueous solubility and pharmacokinetics (PK) in mice. We also evaluated its in vivo biological activity on humoral immune responses using the sheep red blood cells (SRBC)-vaccination mouse model. AP-4-287 had a significant higher aqueous solubility and was readily converted to FX1 in vivo after intraperitoneally (i.p.) administration, but a shorter half-life in vivo. Importantly, AP-4-287 treatment led to a reversible effect on (1) the reduction in the frequency of splenic Ki67 + CD4 + T cells, Tfh cells, and GC B cells; (2) lower GC formation following vaccination; and (3) a decrease in the titers of antigen-specific IgG and IgM antibodies. Our study advances the preclinical development of drug targeting BCL6 BTB domain for the treatment of diseases that are associated with abnormal BCL6 elevation., (© 2021 Wiley-VCH GmbH.)

Thiazolidinediones (TZD), benzopyrans are the proven scaffolds for inhibiting Aldose reductase (ALR2) activity and their structural confluence with the retention of necessary fragments helped in designing a series of hybrid compounds 2-(5-cycloalkylidene-2,4-dioxothiazolidin-3-yl)-N-(2-oxo-2H-chromen-3-yl)acetamide (10a-n) for better ALR2 inhibition. The compounds were synthesized by treating substituted 3-(N-bromoacetyl amino)coumarins (9a-d) with potassium salt of 5-cyclo alkylidene-1,3-thiazolidine-2,4-diones (4a-d). The inhibition activity against ALR2 with IC 50 values range from 0.012 ± 0.001 to 0.056 ± 0.007 μM. N-[(6-Bromo-3-coumarinyl)-2-(5-cyclopentylidene-2,4-dioxothiazolidin-3-yl)] acetamide (10c) with cyclopentylidene group on one end and the 6-bromo group on the other end showed better inhibitory property (IC 50  = 0.012 μM) and selectivity index (324.166) against the ALR2, a forty fold superiority over sorbinil, a better molecule over epalrestat and rest of the analogues exhibited a far superior response over sorbinil and slightly better as compared with epalrestat. It was further confirmed by the insilico studies that compound 10c showed best inhibition activity among the synthesized compounds with a high selectivity index against the ALR2. In invivo experiments, supplementation of compound 10c to STZ induced rats delayed the progression of cataract in a dose-dependent manner warranting its further development as a potential agent to treat thediabetic secondary complications especially cataract., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Purpose: Combination therapy with insulin-independent sodium-glucose cotransporter 2 inhibitors and thiazolidinedione drugs, such as lobeglitazone, has been reported to elicit potential additive efficacy in glycemic control in type 2 diabetes mellitus. This study was conducted to evaluate the pharmacokinetic (PK) drug-drug interactions between empagliflozin and lobeglitazone in healthy subjects., Subjects and Methods: A randomized, open-label, multiple-dose study was conducted in 30 healthy subjects using a three-treatment, six-sequence, three-way crossover design. Subjects received one of the following treatments once daily for 5 days in each period: 25 mg empagliflozin, 0.5 mg lobeglitazone sulfate, or a combination. Serial blood sampling before every dose and up to 24 h after the last dose was performed during each treatment period. The PK parameters were estimated using noncompartmental methods with the plasma empagliflozin and lobeglitazone concentrations. The absence of a PK interaction was construed as the 90% confidence interval (90% CI) of maximum concentration at steady state (C max,ss ) and area under the concentration-time curve over the dosing interval (AUC tau ) for combination therapy-to-monotherapy ratios within the limits of 0.80-1.25., Results: The steady-state plasma empagliflozin and lobeglitazone concentration-time profiles of combination therapy and monotherapy were comparable in the 25 subjects who completed the study. Coadministration of empagliflozin with lobeglitazone did not affect empagliflozin PK (with 90% CIs of 0.956-1.150 and 0.945-1.133 for C max,ss and AUC tau , respectively). Likewise, empagliflozin did not affect lobeglitazone C max,ss or AUC tau (with 90% CIs of 0.869-0.995 and 0.851-1.018, respectively). All treatment groups tolerated mild adverse events well., Conclusion: The lack of PK interactions between lobeglitazone and empagliflozin in combination therapy, along with their good tolerability, indicates that the two drugs can be coadministered without dose adjustment., Trial Registration Number: NCT02854748, Registered on August 7, 2016., Competing Interests: The authors report no conflicts of interest in this work., (© 2021 Kim et al.)

Purpose: Patients with type 2 diabetes mellitus require strict blood glucose control, and combination therapy with a thiazolidinedione and dipeptidyl peptidase-4 inhibitors, such as lobeglitazone and sitagliptin, is one of the recommended treatments. The objective of this study was to investigate a possible pharmacokinetic interaction between lobeglitazone and sitagliptin after multiple oral administrations in healthy Korean men., Methods: Two randomized, open-label, multiple-dose, 2-way crossover studies were conducted simultaneously in healthy men. In study 1, men were randomly assigned to 1 of 2 sequences, and 1 of the following treatments was administered in each period: 1 tablet of lobeglitazone sulfate (0.5 mg) once daily for 5 days and or 1 tablet each of lobeglitazone sulfate (0.5 mg) and sitagliptin (100 mg) once daily for 5 days. In study 2, men were also randomly assigned to 1 of 2 sequences and the treatments were as follows: 1 tablet of sitagliptin (100 mg) once daily for 5 days or 1 tablet each of sitagliptin (100 mg) and lobeglitazone sulfate (0.5 mg) once daily for 5 days. Serial blood samples were collected up to 48 h after dosing on the fifth day. Plasma drug concentrations were measured by LC-MS/MS. Pharmacokinetic parameters, including C max,ss and AUC 0-τ , were determined by noncompartmental analysis. The geometric least-square mean (GLSM) ratios and associated 90% CIs of log-transformed C max,ss and AUC 0-τ for separate or coadministration were calculated to evaluate pharmacokinetic interactions., Findings: Nineteen men from study 1 and 17 from study 2 completed the pharmacokinetic sampling and were included in the analyses. The GLSM ratios of C max,ss and AUC 0-τ were 0.9494 (95% CI, 0.8798-1.0243) and 1.0106 (95% CI, 0.9119-1.1198) for lobeglitazone (from study 1) and 1.1694 (95% CI, 1.0740-1.2732) and 1.0037 (95% CI, 0.9715-1.0369) for sitagliptin (from study 2), respectively., Implications: Except for the slight 17% increase in the sitagliptin C max,ss value, the pharmacokinetic parameters of lobeglitazone and sitagliptin met the pharmacokinetic equivalent criteria when administered separately or in combination. The increase in C max of sitagliptin when coadministered with lobeglitazone would not be clinically significant in practice. ClinicalTrials.gov Identifier: NCT02824874 and NCT02827890., Competing Interests: Disclosures The authors have indicated that they have no conflicts of interest regarding the content of this article., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Thiazolidinediones are known for their activity against Type 2 diabetes and are currently being repurposed for their potent anti-cancer activity. In the present study, we have assessed in vitro metabolic properties and in vivo pharmacokinetic parameters of a novel thiazolidinedione derivative, BIT-15-67, a potential anticancer compound. BIT-15-67 showed low solubility in aqueous buffers at different pH values. The permeability was determined across the Caco-2 monolayer and BIT-15-67 showed high permeability and an efflux ratio of less than 2 suggesting that it is not a substrate of the efflux transporters (P-gp & BCRP). The plasma protein binding was evaluated by equilibrium dialysis and the compound exhibited moderate binding to mouse and rat plasma proteins. BIT-15-67 was stable (half-life > 30 min.) in mouse, rat, dog and human liver microsomes and unstable (half-life <15 min.) in rat hepatocytes suggesting possible Phase II metabolism. Liquid chromatography-tandem mass spectrometry was used to identify Phase I and Phase II metabolites. One of each Phase I and Phase II metabolites have been identified in rat hepatocytes samples. The BIT-15-67 is not an inhibitor of CYP1A2, CYP2C9, CYP2C19, CYP2D6 and CYP3A4. The PK parameters were determined in both male and female Wistar rats after single intravenous dose administration of BIT-15-67. In rats, the mean plasma clearance of BIT-15-67 was higher in males than in females and the terminal plasma elimination half-life was shorter in males than in females. The compound was highly distributed in the tissues. Overall, the absolute oral bioavailability was 5-fold higher in females (38 %) than in males (7 %). In female nude mice with tumors, BIT-15-67 was well distributed among the collected tissues with the highest concentration in the liver. The ratio of the concentrations in tumor vs. the plasma was 0.5 which could be an important attribute in the development of the compound for anti-cancer research., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Purpose: Coadministration of lobeglitazone and dapagliflozin is expected to result in a blood glucose-lowering effect, followed by a gradual increase, in clinical usage; however, combining drugs could cause negative interactions. This study aimed to evaluate the effect of the coadministration of lobeglitazone and dapagliflozin on their individual pharmacokinetic properties at steady state in healthy male volunteers in the fasted state., Methods: This study consisted of 2 parts, each of which was a randomized, open-labeled, multiple-dose, 2-way crossover study in 20 healthy male volunteers in each part. Blood samples were taken periodically over a 48-h period after dosing to derive total plasma lobeglitazone and dapagliflozin pharmacokinetic properties; safety profile was evaluated throughout the study., Findings: When the pharmacokinetic properties of dapagliflozin were evaluated following its administration alone and in combination with lobeglitazone, point estimate and 90% CI of the geometric mean ratio of dapagliflozin AUC τ were entirely within the conventional bioequivalence range of 80%-125%. However, although it was not clinically meaningful, its C ss,max was ~8% lower in subjects receiving multiple doses of dapagliflozin and lobeglitazone than that in those administered dapagliflozin alone. The pharmacokinetic properties of lobeglitazone were evaluated following its administration alone and in combination with dapagliflozin. The geometric mean ratios and 90% CIs of the lobeglitazone C ss,max and AUC τ were within the conventional bioequivalence range of 80%-125%., Implications: Coadministration of lobeglitazone and dapagliflozin had no apparent clinically relevant effects on the pharmacokinetic properties of either drug. Based on these findings, it is anticipated that lobeglitazone and dapagliflozin can be coadministered without dose adjustment. ClinicalTrials.gov identifier: NCT03616392., Competing Interests: Disclosures This work was supported by Chong Kun Dang Pharmaceutical Co Ltd. Chong Kun Dang Pharmaceutical was responsible for monitoring and reviewing the analyses and the report of this study, and also provided protocol-specific training for all investigators and responsible study site staff. Study protocol procedures, study requirements, and Korean Good Clinical Practice responsibilities were reviewed by Chong Kun Dang Pharmaceutical. Chong Kun Dang Pharmaceutical did not fund medical writing support for this article, and the authors made the final decision to submit the article for publication. The authors have indicated that they have no other conflicts of interest with regard to the content of this article., (Copyright © 2020 Elsevier Inc. All rights reserved.)

&nbsp; In an effort to improve the antimicrobial activity of norfloxacin, a series of hybrid norfloxacin-thiazolidinedione molecules were synthesized and screened for their direct antimicrobial activity and their anti-biofilm properties. The new hybrids were intended to have a new binding mode to DNA gyrase, that will allow for a more potent antibacterial effect, and for activity against current quinolone-resistant bacterial strains. Moreover, the thiazolidinedione moiety aimed to include additional anti-pathogenicity by preventing biofilm formation. The resulting compounds showed promising direct activity against Gram-negative strains, and anti-biofilm activity against Gram-positive strains. Docking studies and ADMET were also used in order to explain the biological properties and revealed some potential advantages over the parent molecule norfloxacin., Competing Interests: The authors declare no conflict of interest.

Thiazolidinediones and quinazolin-4-ones compounds, previously known for their activity against Type 2 diabetes and antifungal activity respectively, are currently being investigated for their anti-cancer activity. The determination of pharmacokinetic parameters for these two classes of compounds using a simultaneous chromatographic method with a low detection limit is a challenge. In this study, a highly sensitive and simultaneous LC-MS/MS-based bioanalytical method was developed and validated in rat plasma for the estimation of four novel anti-cancer compounds, BIT-15-67 and BNT-11, belonging to the Thiazolidinedione class, and BNUA-108 and BNUA-48, from the quinazolin-4-one class. The analytes were extracted from plasma samples by protein precipitation and separated on a short reverse phase Hypersil Phenyl BDS, 50 × 4.6 mm, 2.4 μm column at a column oven temperature of 40 °C. An isocratic mobile phase, a 20:80 (v/v) mixture of 5 mM ammonium acetate solution and acetonitrile containing 0.1% formic acid, was used for the elution at a flow rate of 0.4 mL/min. The analytes and internal standard, sulfaphenazole, were quantified in the multiple reaction monitoring mode using positive electrospray ionization with specific pair of mass by charge ratio. All standard validation parameters were assessed as per current bioanalytical method validation guidelines in rat plasma. The area response for the four analytes was found to be linear over the concentration range of 1.00 to 1000 ng/mL in rat plasma. The signal to noise at LLOQ of 1 ng/mL was adequate for application to different pre-clinical studies. The intra- and inter-day precision were <11% and accuracy deviated -1.8 to 9.60% from the nominal. The mean recovery was high (about 90%) and consistent for all the analytes over the linear dynamic range of the method. This simple, robust and validated method can be employed to determine the rat plasma concentrations of the four selected anticancer compounds in preclinical studies such as the pharmacodynamic and the pharmacokinetic studies including tissue distribution and excretion, and the toxicokinetic studies. In this study, pharmacokinetic parameters were determined using this method for all the four compounds individually following intravenous administration in rats., (Copyright © 2019 Elsevier B.V. All rights reserved.)

This study aimed to compare the pharmacokinetic profile of combined CKD-395 0.5/1000 mg treatment with that of the coadministration of lobeglitazone sulfate 0.5 mg and metformin hydrochloride (HCl) extended-release (XR) 1000 mg and assess the effect of food on the pharmacokinetics of CKD-395 0.5/1000 mg. Two clinical trials were conducted as part of an open-label, single-dose, randomized, 2-period, 2-sequence crossover study. In study 1, a total of 26 subjects received either CKD-395 0.5/1000 mg as a test drug or coadministration of lobeglitazone sulfate 0.5 mg and metformin HCl XR 1000 mg individually as a reference treatment under fed conditions. In study 2, a total of 16 subjects received CKD-395 0.5/1000 mg treatment under either fasted or fed conditions. Blood samples were collected at intervals from 0 to 48 hours. In study 1, the geometric mean ratios and 90% confidence intervals of pharmacokinetic parameters for lobeglitazone and metformin were all within 80%-125% in the fed condition. In study 2, there were no high-fat meal effects on the area under the curve extending up to the last sampling time (AUC last ) of lobeglitazone, but there was a decrease in the maximum plasma concentration (C max ) of lobeglitazone by approximately 32% in the fed condition. Although the AUC last of metformin increased by approximately 70% in the fed condition, there was no effect of food on the C max of metformin, which is consistent with the already-established food effect on metformin HCl XR. No adverse drug reactions or serious adverse events were observed. This study suggests that CKD-395 0.5/1000 mg exhibits similar exposure and absorption rates to coadministration of single agents and is well tolerated under both fasted and fed conditions., (© 2018, The American College of Clinical Pharmacology.)

Background: SKLB023, a novel 5-benzylidenethiazolidine-2,4-dione based-derivative, specifically inhibits inducible nitric oxide synthase and shows promise for treating non-alcoholic steatohepatitis (NASH). However, its poor water solubility and low bioavailability limits its clinical use. Here the drug was loaded into phosphatidylcholine-bile salt-mixed micelles (PBMM/SKLB023) to overcome these limitations. Methods: PBMM/SKLB023 was developed using a simple co-precipitation method, and formulation parameters were optimized. The pharmacokinetics of PBMM/SKLB023 were investigated in Wistar rats, and therapeutic efficacy was assessed in a mouse model of NASH induced by a diet deficient in methionine- and choline. Results: PBMM/SKLB023 particles were 11.36±2.08 nm based on dynamic light scattering, and loading the drug into micelles improved its water solubility 300-fold. PBMM/SKLB023 inhibited proliferation and activation of HSC-T6 cells more strongly than free SKLB023. PBMM/SKLB023 showed longer mean retention time and higher bioavailability than the free drug after intravenous injection in Wistar rats. In the mouse model of NASH, PBMM/SKLB023 alleviated hepatic lipid accumulation, inflammation, and fibrosis to a significantly greater extent than free SKLB023. Conclusion: PBMM/SKLB023 shows therapeutic potential for treating NASH and liver fibrosis., Competing Interests: The authors report no conflicts of interest in this work.

Objective: This study was conducted to evaluate the pharmacokinetics and bioequivalence of two formulations of -DuvieTM (0.5-mg lobeglitazone sulfate)., Materials and Methods: This study was designed as an open-label, randomized, single-dose, crossover bioequivalence study in healthy male subjects. A total of 28 subjects were randomized into two groups: one group received the test drug, 0.5-mg DuvieTM tablets, which have formulations available on the global market; and the other group received the reference drug, the initially-approved 0.5-mg DuvieTM tablets. Plasma samples were collected for up to 48 hours after drug treatment and were analyzed for lobeglitazone using validated liquid chromatography-tandem mass spectrometry. Individual pharmacokinetic properties were determined by noncompartmental methods. Safety assessments were performed., Results: 28 subjects completed the study and were included in the pharmacokinetic analysis. The mean (standard deviation) values of -AUClast for the test and reference formulations were 367.49 (157.92) and 362.40 (140.05) ng×h/mL, respectively. The mean (standard deviation) values of Cmax for the test and reference formulations were 50.35 (6.94) and 49.29 (6.71) ng/mL, respectively. The 90% confidence intervals for AUClast and Cmax were 0.9150 - 1.1088 and 0.9879 - 1.0561, respectively. All adverse events were mild, and there were no serious adverse events., Conclusion: This study suggests that the two lobeglitazone tablet formulations have similar exposure and absorption rates. Therefore, the newly-developed formulation of the 0.5-mg DuvieTM tablet is expected to contribute to the treatment of patients with type 2 diabetes.
.

Methotrexate (MTX) is the standard of care in the treatment of rheumatoid arthritis (RA), a common autoimmune disease that is characterized by chronic inflammation in the synovial membrane of joints. Unfortunately, MTX suffers from high discontinuation rates due to a large variability in efficacy and, in particular, adverse effects. As inflammation is associated with elevated levels of reactive oxygen species (ROS) like H 2 O 2 , we propose to improve treatment through site-selective delivery of MTX to inflammatory tissue by use of a H 2 O 2 sensitive MTX prodrug. To establish proof proof-of-concept, two novel H 2 O 2 sensitive, thiazolidinone-based MTX prodrugs were synthesized and evaluated for this purpose. MTX-γ-thiazolidinone (MTX-γ-TZ) exhibited the most promising properties - good to high chemical and metabolic stability, excellent aqueous solubility, while being activated when subjected to patho-physiological concentrations of H 2 O 2 . In vivo, MTX-γ-TZ exhibited comparable efficacy to MTX in a murine collagen type II-induced arthritis (CIA) model while treated mice showed indications of reduced toxicity as their body weight decreased less towards the end of the study, compared to the MTX-treated group., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)

Background: Peroxisome proliferator-activated receptor- (PPAR-) γ plays critical roles in human metabolic disorders and has recently been implicated as a regulator of cellular proliferation and inflammatory responses. Regulatory T cells (Tregs), which express high levels of PPAR- γ protein, have the ability to maintain immune tolerance to self-antigens and regulate immune response to Schistosoma infection. However, mechanisms involved in the resolution of these responses are elusive., Methods: Liver and spleen tissue samples in Schistosoma japonicum -infected mice after administration of pioglitazone (a PPAR- γ agonist) were collected. The hepatic and splenic pathologies were detected by H&E and Masson staining. The percentages of Th1/2 and Treg cells in the liver and spleen of each mouse were determined using flow cytometry. Levels of gene expression of PPAR- γ and Foxp3 in tissues or cells were determined using real-time PCR (RT-PCR). Macrophages were treated with pioglitazone in vitro or cocultured with normal purified CD4 + T cells for detecting Treg cells by flow cytometry. The interactions of PPAR- γ with Foxp3 in CD4 + T cells were detected by coimmunoprecipitation., Results: Administration of pioglitazone resulted in the prevention of the development of hepatic and splenic pathologies. Activation of PPAR- γ by pioglitazone resulted in increased percentages of CD4 + CD25 + Foxp3 + Treg cells and decreased percentages of CD3 + CD4 + IFN- γ + and CD3 + CD4 + IL-4 + cells in the liver and spleen of Schistosoma japonicum -infected mice. In addition, the PPAR- γ agonist can induce Treg cells in vitro directly or by modulating the macrophage's function indirectly. Furthermore, through interaction with Foxp3 in CD4 + T cells, the PPAR- γ agonist can promote the expression of Foxp3; however, the inhibitor of PPAR- γ weakened the expression of Foxp3 by modifying the coexpression of Foxp3 and PPAR- γ ., Conclusions: Our study reveals a previously unrecognized role for PPAR- γ /Foxp3 signaling in regulating the immunopathology that occurs during Schistosoma infection through induction of Treg cells.

Background: A series of (E)-5-(4-((Z)-4-substitutedbenzylidene-2-thienylmethylene-5-oxo- 2-phenyl-4,5-dihydro-1H-imidazol-1-yl) benzylidene)thiazolidine-2,4-diones were synthesized and evaluated for antimycobacterial and antimicrobial activity. All these ligands were docked against protein (InhA) Enoyl-ACP reductase of the type II fatty acid syntase (FAS-II) system, (PDB ID: 4COD)., Objective: In this report, we have designed and synthesized azole scaffolds with good antitubercular activities as there is a real need to develop new candidates with less toxicity and more efficiency toward pathogen. The obtained antimycobacterial activity data have been validated in the terms of ligand-protein interaction and were also analyzed for ADME properties to determine their potential to build up as good oral drug candidates., Methods: All the synthesized compounds have been established by elemental analysis, IR, 1H NMR, 13C NMR and Mass spectral data. In vitro antimycobacterial activity was carried out against (M. tuberculosis) H37Rv strain using Lowenstein-Jensen medium and antimicrobial activity against two gram-positive bacteria (S. aureus, S. pyogenes), two gram-negative bacteria (E. coli, P. aeruginosa) and three fungal species (C. albicans, A. niger, A. clavatus) using the broth microdilution method. In silico molecular docking studies were carried out using Glide (grid-based ligand docking) program incorporated in the Schrödinger molecular modeling package by Maestro 11.0 and ADME properties of synthesized compounds was performed using DruLito software., Results: Compounds 3a, 3b, 3d, 3g, 3i and 3n exhibited promising antimicrobial activity whereas compound 3n showed very good antimycobacterial activity along with Gilde docking score (-8.864) and with the one violation in Lipinski's rule of five., Conclusion: The wet lab result for compound 3n along with Glide XP docking score and the calculated ADME parameters give the best choice for the preparation of new derivatives in order to improve antitubercular activity in future with more improved potency., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.)

The prevalence of hypertension is very common amongst the diabetic patients and is reported as the major cause of mortality in diabetes. Pioglitazone reported to have an ability to alter the blood cholesterol level and cardioprotective efficiency along with its antidiabetic activity. Telmisartan, through activation of PPAR-γ receptor exerts insulin sensitizing property in addition to its primary cardioprotective efficiency. Theoretically, a combination of pioglitazone and telmisartan may be beneficial to effectively control the high blood glucose level and management of coexisting cardiovascular complication in diabetes. The aim of this research was to experimentally evaluate the pharmacokinetic interaction of pioglitazone and telmisartan when are coadministered in rat. Pioglitazone and telmisartan were administered orally as a single dose individually and in combination to the rats. The plasma samples of the pharmacokinetic study were analyzed using a validated LCMS method. The acute toxicity of the combination with a high dose in rats was also evaluated as a part of the determination of its safety profile. There was no significant change in pharmacokinetic parameters were resulted due to the coadministration of pioglitazone and telmisartan in rat. Absence of major toxicological effect supports the in vivosafety of the combination., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Inter-individual variability in pharmacokinetics can lead to unexpected side effects and treatment failure, and is therefore an important factor in drug development. CYP2C8 is a major drug-metabolizing enzyme known to be involved in the metabolism of over 100 drugs. In this study, we predicted the inter-individual variability in AUC/Dose of CYP2C8 substrates in healthy volunteers using the Monte Carlo simulation. Inter-individual variability in the hepatic intrinsic clearance of CYP2C8 substrates (CL int,h,2C8 ) was estimated from the inter-individual variability in pharmacokinetics of pioglitazone, which is a major CYP2C8 substrate. The coefficient of variation (CV) of CL int,h,2C8 was estimated to be 40%. Using this value, the CVs of AUC/Dose of other major CYP2C8 substrates, rosiglitazone and amodiaquine, were predicted to validate the estimated CV of CL int,h,2C8 . As a result, the reported CVs of both substrates were within the 2.5-97.5 percentile range of the predicted CVs. Furthermore, the CVs of AUC/Dose of the CYP2C8 substrates loperamide and chloroquine, which are affected by renal clearance, were also successfully predicted. Combining this value with previously reported CVs of other CYPs, we were able to successfully predict the inter-individual variability in pharmacokinetics of various drugs in clinical., (Copyright © 2017 The Japanese Society for the Study of Xenobiotics. Published by Elsevier Ltd. All rights reserved.)

The insulin sensitizing glitazone drugs, rosiglitazone (ROS) and pioglitazone (PGZ) both have anti-proliferative and anti-inflammatory effects and induce adipose tissue (fat) to produce the vaso-protective protein adiponectin. Stenosis due to intimal hyperplasia development often occurs after placement of arteriovenous synthetic grafts used for hemodialysis. This work was performed to characterize the in vitro and in vivo effects of ROS or PGZ incorporation in fat and to determine if fat/PGZ depots could decrease vascular hyperplasia development in a porcine model of hemodialysis arteriovenous graft stenosis. Powdered ROS or PGZ (6-6000μM) was mixed with fat explants and cultured. Drug release from fat was quantified by HPLC/MS/MS, and adiponectin and monocyte chemotactic protein-1 (MCP-1) levels in culture media were measured by ELISA. The effect of conditioned media from the culture of fat with ROS or PGZ on i) platelet-derived growth factor-BB (PDGF-BB)-stimulated proliferation of human venous smooth muscle cells (SMC) was measured by a DNA-binding assay, and ii) lipopolysaccharide (LPS)-induced human monocyte release of tumor necrosis factor-alpha (TNFα) was assessed by ELISA. In a porcine model, pharmacokinetics of PGZ from fat depots transplanted perivascular to jugular vein were assessed by HPLC/MS/MS, and retention of the fat depot was monitored by MRI. A porcine model of synthetic graft placed between carotid artery and ipsilateral jugular vein was used to assess effects of PGZ/fat depots on vascular hyperplasia development. Both ROS and PGZ significantly induced the release of adiponectin and inhibited release of MCP-1 from the fat. TNF production from monocytes stimulated with LPS was inhibited 50-70% in the presence of media conditioned by fat alone or fat and either drug. The proliferation of SMC was inhibited in the presence of media conditioned by fat/ROS cultures. Fat explants placed perivascular to the external jugular vein were retained, as confirmed by MRI at one week after placement. PGZ was detected in the fat depot, in the external jugular vein wall and in adjacent tissue at clinically relevant levels, whereas levels in plasma were below detection. External jugular vein exposed to fat incorporated with PGZ had increased adiponectin expression compared to vein exposed to fat alone. However, the development of hyperplasia within the arteriovenous synthetic grafts was unchanged by treatment with fat/PGZ depots compared to no treatment., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Although the mechanism of action for peroxisome proliferator-activated receptor gamma (PPARγ) agonists has been extensively explored, the impact of the pharmacokinetic (PK) profile on the pharmacodynamic (PD) effects of PPARγ agonists has not been elucidated in detail. The importance of the PK profile of PPARγ agonist was evaluated for its PD effect based on population PK/PD analysis. Pioglitazone hydrochloride, the PPARγ agonist, was administered orally to Wistar fatty rats once a day (q.d.) or once every other day (q.2d.) as double the amount for the q.d., Treatment: The plasma glucose lowering effect was selected as a surrogate PD effect for an anti-diabetic effect. The model fitting was conducted using the non-linear mixed effect modeling (NONMEM) method. The indirect response model described well the plasma glucose concentration-time profile. The q.d. treatment showed a stronger impact on the plasma glucose lowering effect than did the q.2d., Treatment: The results of PK/PD modeling suggested that the sensitivity (i.e. EC 50 ) between each group was comparable. On the other hand, the time above the effective concentration in the q.d. treatment group was longer than that in the q.2d. treatment group. The simulation of various dose regimens suggested that the much longer exposure duration within the effective level showed a stronger plasma glucose lowering effect, even with identical exposure to pioglitazone in the plasma. The PK/PD analysis clarified that the PK profile affected the pharmacological response and that continuous exposure at an appropriate effective level would be efficient for the anti-diabetic effect of the PPARγ agonist., (Copyright © 2017 John Wiley & Sons, Ltd.)

The purpose of this study was to evaluate in vivo supersaturation/precipitation/absorption behavior in the gastrointestinal (GI) tract based on the luminal concentration-time profiles after oral administration of pioglitazone (PG, a highly permeable lipophilic base) and its hydrochloride salt (PG-HCl) to rats. In the in vitro precipitation experiment in the classic closed system, while the supersaturation was stable in the simulated gastric condition, PG drastically precipitated in the simulated intestinal condition, particularly at a higher initial degree of supersaturation. Nonetheless, a drastic and moderate improvement in absorption was observed in vivo at a low and high dose of PG-HCl, respectively. Analysis based on the luminal concentration of PG after oral administration of PG-HCl at a low dose revealed that most of the dissolved PG emptied from the stomach was rapidly absorbed before its precipitation in the duodenum. At a high dose of PG-HCl, PG partly precipitated in the duodenum but was absorbed to some extent. Therefore, the extent of the absorption was mainly dependent on the duodenal precipitation behavior. Furthermore, a higher-than expected absorption after oral administration of PG-HCl from in vitro precipitation study may be due to the absorption process in the small intestine, which suppresses the precipitation by removal of the drug. This study successfully clarify the impact of the absorption process on the supersaturation/precipitation/absorption behavior and key absorption site for a salt formulation of a highly permeable lipophilic base based on the direct observation of in vivo luminal concentration. Our findings may be beneficial in developing an ideal physiologically based pharmacokinetic model and in vitro predictive dissolution tools and/or translating the in silico and in vitro data to the in vivo outcome., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Background and Objectives: S49076 is a novel ATP-competitive tyrosine kinase inhibitor of MET, AXL and FGFR with a unique selectivity profile. A phase I open-label study was undertaken to establish the tolerability profile and determine the recommended dose (RD) and administration schedule., Materials and Methods: Patients with advanced solid tumours received S49076 orally once-daily (qd) or twice-daily (bid) in continuous 21-day cycles at escalating doses guided by a 3 + 3 design and followed by an expansion phase at the RD. Pharmacokinetic (PK) parameters were assessed and pharmacodynamic end-points were evaluated in pre- and post-treatment tumour biopsies. Preliminary anti-tumour activity was evaluated as per the Response Evaluation Criteria In Solid Tumours 1.1 criteria., Results: A total of 103 patients were treated: 79 in the dose-escalation and 24 in the expansion. Doses from 15 to 900 mg were evaluated. Dose-limiting toxicities were reported in 9 patients and occurred at 30, 760 and 900 mg in the qd arm and at 180, 225 and 285 mg in the bid arm. The RD was defined at 600 mg qd. Adverse events (AEs) occurred with similar frequency in both regimens at an equivalent total daily dose. Overall, 83 patients (81.4%) had drug-related AEs, the majority (93%) of which were grade I-II (National Cancer Institute Common Terminology Criteria for Adverse Events version 4.0) and only 3% led to drug discontinuation. Intratumoural PK analysis at the RD suggested hitting of MET, AXL and FGFR., Conclusion: S49076 demonstrated a tolerable safety profile with limited single-agent activity. PK/pharmacodynamic readouts of S49076 are encouraging for further investigation of S49076 in combination therapies., Trial Registration Number: ISRCTN00759419., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

A new fast LC-MS/MS method was developed for determination of alogliptin and pioglitazone in human plasma. Linearity ranges of 10-400ngmL -1 for alogliptin and 25-2000ngmL -1 for pioglitazone, were found to be suitable for their bioanalysis covering the C min and C max values of the drugs. Direct precipitation technique was used for simultaneous extraction of the drugs successfully from human plasma samples. Chromatographic separation was achieved on a BEH C 18 column (50mm×2.1mm, 1.7μm) with 0.1% aqueous formic acid: acetonitrile (40:60, v/v) at a flow rate of 0.3mLmin -1 . The validated method was applied to a preliminary pharmacokinetic study on human volunteers. Monitoring the transition pairs of m/z 340.18 to 116.08 for alogliptin and m/z 356.99 to 133.92 for pioglitazone, using triple quadrupole mass spectrometer with multiple reaction monitoring, was achieved in the positive mode. The validated method is accurate and suitable for further clinical applications and possible bioequivalence studies., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Typically, concentration-response curves are based upon nominal inducer concentrations for in-vitro-to-in-vivo extrapolation of CYP3A4 induction. The limitation of this practice is that it assumes the hepatocyte culture model is a static system. We assessed whether correcting for: 1) changes in perpetrator concentration in the induction medium during the incubation period, 2) perpetrator binding to proteins in the induction medium, and 3) nonspecific binding of perpetrator can improve the accuracy of CYP3A4 induction predictions. Of the seven compounds used in this evaluation, significant parent loss and nonspecific binding were observed for rifampicin (29.3-38.3%), pioglitazone (64.3-78.6%), and rosiglitazone (57.1-75.5%). As a result, the free measured EC 50 values (EC 50u ) of pioglitazone, rosiglitazone, and rifampicin were significantly lower than the nominal EC 50 values. In general, the accuracy of the induction predictions, using multiple static models, improved when corrections were made for measured medium concentrations, medium protein binding, and nonspecific binding of the perpetrator, as evidenced by 18-29% reductions in the root mean square error. The relative induction score model performed better than the basic static and mechanistic static models, resulting in lower prediction error and no false-positive or false-negative predictions. However, even when the EC 50u value was used, the induction prediction for bosentan, which is a substrate of organic anion transporter proteins, was overpredicted by approximately 2-fold. Accounting for the ratio of unbound intracellular concentrations to unbound medium concentrations (K puu,in vitro ) (0.5-7.5) and the predicted multiple-dose K puu,in vivo (0.6) for bosentan resulted in induction predictions within 35% of the observed interaction., (Copyright © 2017 by The American Society for Pharmacology and Experimental Therapeutics.)

Background and Objectives: Pioglitazone is a thiazolidinedione antihyperglycemic drug with insulin-sensitizing properties. We investigated whether the variant genotypes of cytochrome P450 2C8 (CYP2C8), CYP2C9, CYP3A5 and transporter ABCB1 influence the pharmacokinetic phenotype of the substrate pioglitazone in Chinese individuals., Participants and Methods: Single-nucleotide polymorphisms were determined by the PCR-restriction fragment length polymorphism method in 244 (CYP2C8 and CYP2C9) healthy Chinese Han individuals. After a single oral dose of 30 mg pioglitazone, the plasma concentrations of the parent drug and of two major active metabolites M-III and M-IV were measured using a validated LC-MS/MS in 21 (genotyping CYP3A5 and ABCB1) of these 244 volunteers., Results: The results confirmed that the unique frequencies of CYP2C8*2 (0.0%), CYP2C8*3 (0.0%), and CYP2C9*2 (0.0%) alleles were significantly different from those reported in Whites and Africans, and there were only 10 variant CYP2C9*1/*3 heterozygous (CYP2C9*3 carriers) among 244 Chinese individuals. These results were similar to those reported in Asian ethnic populations, including the Chinese. Unexpectedly, the pioglitazone AUC0-48 in CYP2C9*3 carriers was lower (50.8%), whereas the AUC0-48 ratios of metabolites M-III/pioglitazone and M-IV/pioglitazone increased to 134.3 and 155.8%, respectively, compared with the wild-type CYP2C9*1/*1 homozygous. Moreover, this phenomenon was not observed in individuals with genetic variants of CYP3A5*3 and ABCB1 (C1236T)., Conclusion: The present research suggests that the CYP2C8, CYP3A5, and ABCB1 genes play no significant role in the interindividual variation of pioglitazone pharmacokinetics, whereas CYP2C9*3 carriers are likely to accelerate the metabolism of this antidiabetic drug in the Chinese Han ethnic population.

Cytochrome P450 enzymes and human organic anion transporting polypeptide (OATP) 1B1 are reported to be involved in the pharmacokinetics of lobeglitazone (LB), a new peroxisome proliferator-activated receptor γ agonist. Atorvastatin (ATV), a substrate for CYP3A and human OATP1B1, is likely to be coadministered with LB in patients with the metabolic syndrome. We report herein on a study of potential interactions between LB and ATV in rats. When LB was administered intravenously with ATV, the systemic clearance and volume of distribution at steady state for LB remained unchanged (2.67 ± 0.63 ml/min per kg and 289 ± 20 ml/kg, respectively), compared with that of LB without ATV (2.34 ± 0.37 ml/min per kg and 271 ± 20 ml/kg, respectively). Although the tissue-to-plasma partition coefficient (K p ) of LB was not affected by ATV in most major tissues, the liver K p for LB was decreased by ATV coadministration. Steady-state liver K p values for three levels of LB were significantly decreased as a result of ATV coadministration. LB uptake was inhibited by ATV in rat OATP1B2-overexpressing Madin-Darby canine kidney cells and in isolated rat hepatocytes in vitro. After incorporating the kinetic parameters for the in vitro studies into a physiologically based pharmacokinetics model, the characteristics of LB distribution to the liver were consistent with the findings of the in vivo study. It thus appears that the distribution of LB to the liver is mediated by the hepatic uptake of transporters such as rat OATP1B2, and carrier-mediated transport is involved in the liver-specific drug-drug interaction between LB and ATV in vivo., (Copyright © 2017 by The American Society for Pharmacology and Experimental Therapeutics.)

Background: Millions of people today use herbs either as food or in the form of medicine along with other medications. Many of the herbs can interact with these medications, causing either potentially dangerous side effects or improved or reduced benefits from the medication., Objective: The present study was performed to determine the influence of cinnamon, on the pharmacokinetics and pharmacodynamics of pioglitazone., Method: Studies were conducted in normal and alloxan induced diabetic rats and rabbits with oral administration of selected doses of pioglitazone, cinnamon and their combination. Blood samples were collected at regular intervals of time and were analysed for glucose by GOD/POD method and for pioglitazone by HPLC method respectively. Body weights were also measured every week., Results: Significant differences were seen in pharmacokinetic parameters of pioglitazone like AUC, t1/2, Ke, Cl/F, Vd/F when given in combination with cinnamon in normal and diabetic rabbits. The combination of pioglitazone and cinnamon was found to reduce the glucose levels and body weights significantly than pioglitazone. The results indicating increased AUC of pioglitazone on pretreatment with cinnamon suggest an interaction indicating decreased metabolism of pioglitazone as a result of CYP 3A4 inhibition and thereby producing a potentiating effect., Conclusion: Cinnamon enhanced the bioavailability of pioglitazone by inhibiting the CYP3A4 enzyme. Hence, cinnamon might be beneficial when used in combination with pioglitazone in diabetic patients and an adjustment of dose of pioglitazone may be necessary., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.)

Background: Severe forms of non-alcoholic fatty liver disease (NAFLD) adversely affect the liver physiology and hence the pharmacokinetics of drugs. Here, we investigated the effect of NAFLD on the pharmacokinetics of rosiglitazone, an insulin sensitizer used in the treatment of type 2 diabetes., Methods: Male C57BL/6 mice were divided into two groups. The first group (n=14) was fed with normal chow feed and the second group (n=14) was fed with 60% high-fat diet (HFD) and 40% high fructose liquid (HFL) for 60 days to induce NAFLD. The development of NAFLD was confirmed by histopathology, liver triglyceride levels and biochemical estimations, and used for pharmacokinetic investigations. Rosiglitazone was administered orally at 30 mg/kg dose. At predetermined time points, blood was collected and rosiglitazone concentrations were determined using LC/MS/MS. Plasma concentrations were subjected to non-compartmental analysis using Phoenix WinNonlin (6.3), and the area under the plasma concentration-time curve (AUC) was calculated by the linear-up log-down method., Results: HFD and HFL diet successfully induced NAFLD in mice. Rosiglitazone pharmacokinetics in NAFLD animals were altered significantly as compared to healthy mice. Rosiglitazone exposure increased significantly in NAFLD mice (2.5-fold higher AUC than healthy mice). The rosiglitazone oral clearance was significantly lower and the mean plasma half-life was significantly longer in NAFLD mice as compared to healthy mice., Conclusions: The NAFLD mouse model showed profound effects on rosiglitazone pharmacokinetics. The magnitude of change in rosiglitazone pharmacokinetics is similar to that observed in humans with moderate to severe liver disease. The present animal model can be utilized to study the NAFLD-induced changes in the pharmacokinetics of different drugs.

The Zucker diabetic fatty (ZDF) rat, an inbred strain of obese Zucker fatty rat, develops early onset of insulin resistance and displays hyperglycemia and hyperlipidemia. The phenotypic changes resemble human type 2 diabetes associated with obesity and therefore the strain is used as a pharmacological model for type 2 diabetes. The aim of the current study was to compare the pharmacokinetics and hepatic metabolism in male ZDF and Sprague-Dawley (SD) rats of five antidiabetic drugs that are known to be cleared via various mechanisms. Among the drugs examined, metformin, cleared through renal excretion, and rosiglitazone, metabolized by hepatic cytochrome P450 2C, did not exhibit differences in the plasma clearance in ZDF and SD rats. In contrast, glibenclamide, metabolized by hepatic CYP3A, canagliflozin, metabolized mainly by UDP-glucuronosyltransferases (UGT), and troglitazone, metabolized by sulfotransferase and UGT, exhibited significantly lower plasma clearance in ZDF than in SD rats after a single intravenous administration. To elucidate the mechanisms for the difference in the drug clearance, studies were performed to characterize the activity of hepatic drug-metabolizing enzymes using liver S9 fractions from the two strains. The results revealed that the activity for CYP3A and UGT was decreased in ZDF rats using the probe substrates, and decreased unbound intrinsic clearance in vitro for glibenclamide, canagliflozin, and troglitazone was consistent with lower plasma clearance in vivo. The difference in pharmacokinetics of these two strains may complicate pharmacokinetic/pharmacodynamic correlations, given that ZDF is used as a pharmacological model, and SD rat as the pharmacokinetics and toxicology strain., (Copyright © 2016 by The American Society for Pharmacology and Experimental Therapeutics.)

The glucose-lowering drug pioglitazone undergoes hepatic CYP2C8-mediated biotransformation to its main metabolites. The antiplatelet drug clopidogrel is metabolized to clopidogrel acyl-β-d-glucuronide, which was recently found to be a strong time-dependent inhibitor of CYP2C8 in humans. Therefore, we studied the effect of clopidogrel on the pharmacokinetics of pioglitazone. In a randomized crossover study, 10 healthy volunteers ingested either 300 mg of clopidogrel on day 1, and 75 mg on days 2 and 3, or placebo. Pioglitazone 15 mg was administered 1 hour after placebo and clopidogrel on day 1. Plasma concentrations of pioglitazone, clopidogrel, and their main metabolites were measured up to 72 hours. Clopidogrel increased the area under the plasma concentration-time curve (AUC0-∞) of pioglitazone 2.1-fold [P < 0.001, 90% confidence interval (CI) 1.8-2.6] and prolonged its half-life from 6.7 to 11 hours (P = 0.002). The peak concentration of pioglitazone was unaffected but the concentration at 24 hours was increased 4.5-fold (range 1.6-9.8; P < 0.001, 90% CI 3.17-6.45) by clopidogrel. The M-IV-to-pioglitazone AUC0-∞ ratio was 49% (P < 0.001, 90% CI 0.40-0.59) of that during the control phase, indicating that clopidogrel inhibited the CYP2C8-mediated biotransformation of pioglitazone. Clopidogrel increases the exposure to pioglitazone by inhibiting its CYP2C8-mediated biotransformation. In consequence, use of clopidogrel may increase the risk of fluid retention and other concentration-related adverse effects of pioglitazone., (Copyright © 2016 by The American Society for Pharmacology and Experimental Therapeutics.)

Breast cancer is one of the most lethal types of cancer in women worldwide due to the late stage detection and resistance to traditional chemotherapy. The human epidermal growth factor receptor 2 (HER2) is considered as a validated target in breast cancer therapy. Even though a substantial effort has been made to develop HER2 inhibitors, only lapatinib has been approved by the U.S. Food and Drug Administration (FDA). Side effects were observed in a majority of the patients within one year of treatment initiation. Here, we took advantage of bioinformatics tools to identify novel effective HER2 inhibitors. The structure-based virtual screening combined with ADMET (absorption, distribution, metabolism, excretion and toxicity) prediction was explored. In total, 11,247 natural compounds were screened. The top hits were evaluated by an in vitro HER2 kinase inhibition assay. The cell proliferation inhibition effect of identified inhibitors was evaluated in HER2-overexpressing SKBR3 and BT474 cell lines. We found that ZINC15122021 showed favorable ADMET properties and attained high binding affinity against HER2. Moreover, ZINC15122021 showed high kinase inhibition activity against HER2 and presented outstanding cell proliferation inhibition activity against both SKBR3 and BT474 cell lines. Results reveal that ZINC15122021 can be a potential HER2 inhibitor.

Despite the fact that fetal drug exposure is common, the disposition of drugs in the fetus is poorly understood. This study aimed to investigate fetal placental and non-placental disposition of rosiglitazone in the pregnant ewe. Steady state was reached after day 5 of fetal infusion, and were ∼1.8 fold higher than maternal concentrations (P<0.001). The AUC for fetal rosiglitazone concentration throughout the infusion was inversely correlated with placental and fetal weight. Metabolic activity of the fetal liver microsomes were ∼25 fold lower than maternal microsomes (P<0.001). The findings suggest that trans-placental transfer is the major route through which rosiglitazone is cleared from the fetal compartment, while non-placental hepatic elimination makes only a minor contribution. This supports a limited capacity of the fetus for eliminating this class of drugs, and highlights the potential for drug toxicity when administering pharmacotherapy to the mother/fetus in human pregnancy., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Fostamatinib is a prodrug that undergoes gastrointestinal tract dephosphorylation to form the active metabolite, R406. Here we report its cytochrome P450-inducing potential. In vitro, R406 3 and 10 μM induced CYP2C8 to levels representing 53% and 75%, respectively, of the level achieved by the positive control, rifampicin. Induction of other enzymes was minor. The effect of fostamatinib (100 mg twice daily) on the pharmacokinetics of a single oral 30-mg dose of the CYP2C8 substrate pioglitazone and its metabolite, hydroxy pioglitazone, was then investigated (open-label, nonrandomized, 2-period phase I study [n = 15]). Coadministration of fostamatinib and pioglitazone (vs pioglitazone alone) was associated with lower mean maximum plasma concentration values for pioglitazone (geometric least-squares mean ratio, 82.8; 90% confidence interval, 64.2-106.8) and hydroxy pioglitazone (90.9; 78.6-105.1), an increase in pioglitazone AUC (117.8; 108.4-128.0), a decrease in hydroxy pioglitazone AUC(0-t) (89.7; 78.9-101.9), and an increase in pioglitazone geometric mean t1/2λz (9.4-12.8 hours). No tolerability concerns were identified upon coadministration. These data suggest that although clinical significance has not been formally evaluated, fostamatinib is unlikely to have a clinically significant effect on the pharmacokinetics of pioglitazone (which may be extrapolated to other CYP2C8 substrates). However, vigilance is advised should these agents be prescribed together., (© 2016, The American College of Clinical Pharmacology.)

Objective: Tofogliflozin is an oral hypoglycemic agent with a novel mechanism of action that reduces blood glucose levels by promoting glucose excretion in urine, achieved by selectively inhibiting sodium-glucose co-transporter 2 (SGLT2). We evaluated the effects of several selected anti-type 2 diabetes mellitus (T2DM) drugs-glimepiride, metformin, sitagliptin, pioglitazone, miglitol, nateglinide, and voglibose-on the pharmacokinetics and pharmacodynamics of tofogliflozin, and the effects of tofogliflozin on the pharmacokinetics of these anti-T2DM drugs in healthy male volunteers., Methods: A single dose of either tofogliflozin alone, one of the anti-T2DM drugs alone, or co-administration of tofogliflozin and the anti-T2DM drug was administered to 108 healthy men. Cmax, AUCinf, and cumulative urine glucose excretion after co-administration of tofogliflozin and each of the anti-T2DM drugs was evaluated relative to the values of those parameters after administration of each drug alone., Results: None of the anti-T2DM drugs had any effect on tofogliflozin exposure. Tofogliflozin had no or little effect on the exposure of any anti-T2DM drug. No anti-T2DM drug had any major effect on the cumulative urine glucose excretion induced by tofogliflozin. There were no safety concerns evident after administration of any drug alone or in co-administration., Conclusions: Neither the pharmacokinetics nor the pharmacodynamics of tofogliflozin was affected by any of the anti-T2DM drugs evaluated in this study, nor was the pharmacokinetics of any of the anti-T2DM drugs affected by tofogliflozin in healthy male volunteers., (© Georg Thieme Verlag KG Stuttgart · New York.)

Pioglitazone (PZ) an anti-hyperglycemic agent is used in the treatment of type 2 diabetes. The aim of this study was to design PZ-loaded nanostructured lipid carriers (NLC) to investigate the bioavailability improvement by transdermal delivery. PZ NLCs were prepared using high-pressure homogenization followed by ultrasonication. The NLCs were evaluated for particle size analysis, drug loading, ex vivo skin transport studies and in vivo bioactivity study. The prepared NLCs had a mean size of 166.05 nm and drug loading of 10.41% with flux value of 47.36 µg/cm(2)/h. The entrapment of PZ is >70% in the NLCs with enhancement ratio of 3.2 times. The in vivo pharmacokinetic study showed 2.17 times enhancement in bioavailability study and pharmacodynamics study showed that PZ NLC-based transdermal therapeutic system (PNLG-TTS) lowers blood sugar level in a sustained pattern for a prolonged period of time as compared to Piosys tablet (marketed). The shelf life of the optimized formulation was found to be 1.83 years. These results clearly provide a lead that above NLCs-based TTS is potential controlled release formulation for PZ and could be a promising drug delivery system for the treatment of diabetes.

Background: LPSF/GQ-02 is a promising benzylidene thiazolidinedione that has demonstrated antidiabetic, antidyslipidemic, anti-atherosclerotic properties and can also treat non-alcoholic fatty liver disease. Despite all activity studies of the new compound, its pharmacokinetics are not yet described., Objective: The aim of this study was to perform its first pharmacokinetic profile., Methods: For this purpose a bioanalytical method for the quantitation of 5-(4- Chloro-benzylidene)-3-(4-methylbenzyl)-thiazolidine-2,4-dione (LPSF/GQ-02) was developed and validated. A Waters UPLC chromatographer using a BEH column (2.1x50mm, 1.7μm particle), mobile phase water:acetonitrile (20:80) was used. The range of calibration curve in plasma was 1.9 to 250 ng/mL with r = 0.9997. LPSF/GQ-02 stability was evaluated in rat plasma and buffers at pH 1.2 and 7.4. The pharmacokinetic assay was carried out in male Wistar rats weighing 250-300 g. The animals received LPSF/GQ-02 at 3 mg/kg by intravenous route. The animals were used to perform a preliminary safety study concerning the evaluation of liver and kidney biomarkers (ALT, AST, urea, creatinine)., Results: The obtained pharmacokinetic parameters were elimination half-life of 4.44 h, Cl of 8.00 L/h.kg, Vd of 45.60 L/kg and MRT of 3.79h. No difference was observed for the liver and kidney biomarkers., Conclusion: The intravenous pharmacokinetic parameters are in agreement with a good future posology, even though the plasma concentrations from oral administration were not quantifiable in a dose of 12 mg/kg. The preliminary safety study demonstrated no acute effect of the drug in liver and kidneys. The LPSF/GQ-02 is a new thiazolidinedione that should continue being evaluated for future clinical use.

Purpose: Repaglinide and pioglitazone are both CYP2C8 and CYP3A4 substrates. This study was to determine whether repaglinide has an inhibitory effect on the metabolism of pioglitazone in vitro, in silico and in vivo., Method: In vitro, the effect of repaglinide on the metabolism of pioglitazone was assessed in pooled human liver microsomes. In silico, an IVIVE-PBPK linked model was built with Simcyp®. Then, a randomized, 2-phase cross-over clinical study was conducted in 12 healthy volunteers., Results: Repaglinide showed a strong inhibitory effect on the metabolism of pioglitazone in vitro (Ki  = 0.0757 µm), [I]/Ki  > 0.1. The Simcyp® prediction ratios of AUC and Cmax between the two treatment groups were both about 1.01. The pharmacokinetics of pioglitazone in clinical trials showed no significant difference between these two treatment groups (p > 0.05)., Conclusion: Repaglinide has no significant inhibitory effect on the metabolism of pioglitazone in vivo, which is inconsistent with the in vitro results. The lack of an inhibitory effect was partly due to extensive plasma protein binding and to the high in vivo clearance of repaglinide, for the concentration of repaglinide in vivo was far smaller than in vitro., (Copyright © 2015 John Wiley & Sons, Ltd.)

The objective of this study was to elucidate the chemical structure of the metabolites derived from lobeglitazone (LB) during its incubation with rat liver microsomes and to characterize the kinetics of formation of the major metabolite M1 in vivo. Using high performance liquid chromatography coupled with a hybrid quadrupole linear ion trap, the metabolites were derived from LB during its incubation with rat liver microsomes. From various fragmentation patterns obtained from the metabolites, LB was biotransformed into 5 metabolites in the incubation, in which demethylation and hydroxylation appeared to be the principle metabolic pathways in vitro; Amongst the five primary metabolites, M1, a demethylated derivative of LB, appeared to be the major metabolite of LB, based on a comparison on the peak intensities in the ion chromatogram. In a study of the in vivo kinetics of formation of M1 in rats, the rate of formation of M1 from LB was determined to be 0.252 and 0.216mL/min/kg at doses of 0.5mg/kg and 2mg/kg of LB, respectively, suggesting that the kinetics of M1 formation were linear in the dose range tested. Considering the fact that LB is primarily eliminated by hepatic metabolism in rats, the formation of M1 accounts for approximately 7.50-9.76% of the overall elimination of LB in rats., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Introduction: It can be a challenge to manage glycemic control in patients with type 2 diabetes mellitus (T2DM) and chronic kidney disease (CKD), due to both patient and medication issues. Although most antihyperglycemic medications can be used in mild kidney disease, many medications are either not advised or require dose adjustments in more advanced CKD. This review summarizes product label information, pharmacokinetic and clinical studies, and clinical guidelines relevant to use of antihyperglycemic medications in CKD., Methods: Product labels and guidelines from North America and Europe, as well as pharmacokinetic and clinical studies of diabetes medication use in CKD were identified through Medline and PubMed searches, up to February 2015. Available data are summarized and correlations between treatment recommendations and available research are discussed, as are glycemic targets for patients with CKD., Results: Newer medications have significantly more data available than older medications regarding use in CKD, although larger clinical studies are still lacking for some drugs. As CKD advances, dose adjustment is needed for many medications [numerous dipeptidyl peptidase-4 inhibitors, some insulins, sodium glucose co-transporter 2 (SGLT2) inhibitors], although not for others (thiazolidinediones, meglitinides). Some medications are not recommended for use in more advanced CKD (metformin, SGLT2 inhibitors, some glucagon-like protein-1 receptor agonists) for safety or efficacy reasons. There is not always good alignment between label recommendations, pharmacokinetic or clinical studies, and guideline recommendations for use of these drugs in CKD. In particular, controversy remains about the use of metformin in moderate CKD and appropriate use of liraglutide and sulfonylureas in advanced CKD., Conclusion: Considerable variability exists with respect to recommendations and clinical data for the many antihyperglycemic drugs used in patients with T2DM and CKD., Funding: Eli Lilly and Company.

Although many studies have evaluated the effects of type 2 diabetes mellitus (T2DM) on the pharmacokinetics (PK) of low molecular weight molecules, there is limited information regarding effects on monoclonal antibodies. Our previous studies have reported significant increases in total (2-4 fold) and renal (100-300 fold) clearance of human IgG, an antibody isotype, in Zucker diabetic fatty (ZDF) rats. Pioglitazone treatment incompletely reversed the disease-related PK changes. The objective of this study was to construct a mechanistic model for simultaneous fitting plasma and urine data, to yield physiologically relevant PK parameters. We propose an extended minimal physiologically based PK (mPBPK) model specifically for IgG by classifying organs as either leaky or tight vascular tissues, and adding a kidney compartment. The model incorporates convection as the primary mechanism of IgG movement from plasma into tissues, interstitial fluid (ISF) in extravascular distribution space, and glomerular filtration rate (GFR), sieving coefficient and fraction reabsorbed in the kidney. The model captured the plasma and urine PK profiles well, and simulated concentrations in ISF. The model estimated a 2-4 fold increase in nonrenal clearance from plasma and 30-120 fold increase in renal clearance with T2DM, consistent with the experimental findings, and these differences in renal clearance were related to changes in GFR, sieving coefficient, and proximal tubular reabsorption. In conclusion, the mPBPK model offers a more relevant approach for analyzing plasma and urine IgG concentration-time data than conventional models and provides insight regarding alterations in distributional and elimination parameters occurring with T2DM.

This study was performed to determine biopharmaceutical properties of lobeglitazone (LB), a novel thiazolidinedione-based activator of peroxisome proliferator-activated receptor gamma, in rats. In parallel artificial membrane permeability assay and Madin-Darby canine kidney (MDCK) cell permeability assays of LB, the activator was found to interact with multidrug-resistance protein 1 (MDR1) and OATP1B1. The concentration resulting in 50% inhibition value for LB in MDR1 expressing MDCK cells was approximately 12.5 ± 3.61 μM. LB had adequate stability (i.e., 56% remaining at 0.5 h) in rat liver microsomes. A cytochrome P450 (CYP) inhibitory potency study indicated that LB is primarily interacted with CYP1A2, 2C9, and 2C19. In rats, LB appeared to be readily absorbed after an oral administration (an absolute bioavailability of ∼95%). Following intravenous administration, LB exhibited linear pharmacokinetics in the dose range of 0.5-2 mg/kg. The primary distribution site was the liver but it was also distributed to heart, lungs, and fat tissue. The excretion of LB to the urine, bile, feces, and intestine was insignificant (i.e., <10% of the dose) in rats. These observations suggest that, despite the fact that it interacts with some drug transporters and metabolizing enzymes, the pharmacokinetics of LB were linear with a high oral bioavailability., (© 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.)

Cabozantinib is a small-molecule tyrosine kinase inhibitor that has been approved for the treatment of patients with progressive, metastatic medullary thyroid cancer. In vitro data indicate that (1) cytochrome P450 (CYP) 3A4 is the primary CYP isoenzyme involved in the metabolism of cabozantinib, and (2) CYP2C8 is the CYP isoenzyme most potently inhibited by cabozantinib with potential for in vivo inhibition at clinically relevant plasma exposures. Pharmacokinetic (PK) drug-drug interactions (DDIs) were evaluated clinically between cabozantinib and (1) a CYP3A inducer (rifampin) in healthy volunteers, (2) a CYP3A inhibitor (ketoconazole) in healthy volunteers, and (3) a CYP2C8 substrate (rosiglitazone) in patients with solid tumors. Compared with cabozantinib given alone, coadministration with rifampin resulted in a 4.3-fold higher plasma clearance (CL/F) of cabozantinib and a 77% decrease in cabozantinib plasma AUC0-inf , whereas coadministration with ketoconazole decreased cabozantinib CL/F by 29% and increased cabozantinib AUC0-inf by 38%. Chronic coadministration with cabozantinib resulted in no significant effect on rosiglitazone plasma Cmax , AUC0-24 , or AUC0-inf . In summary, chronic use of strong CYP3A inducers and inhibitors should be avoided when cabozantinib is administered, and cabozantinib at clinically relevant exposures is not anticipated to markedly affect the PK of concomitant medications via CYP enzyme inhibition., (© 2015, The American College of Clinical Pharmacology.)

Purpose: Lobeglitazone, a peroxisome proliferator-activated receptor-γ agonist, was developed for the treatment of diabetes mellitus. Because the prevalence of hypertension is high among patients with diabetes mellitus, lobeglitazone is likely to be used with the antihypertensive drug amlodipine. We evaluated the pharmacokinetic interactions between lobeglitazone and amlodipine in healthy male Korean subjects., Methods: The study used a randomized, open-label, multiple-dose, 3-treatment, 3-period, 6-sequence crossover design. A total of 24 healthy subjects were enrolled. Blood samples for pharmacokinetic analysis were collected according to a planned schedule after 0.5 mg of lobeglitazone and 10 mg of amlodipine were administered alone or concomitantly once per day for 10 days., Findings: A total of 24 healthy male subjects participated in the study (mean [SD] age, 26.6 [3.9] years; weight, 67.8 [5.7] kg; and height, 173.6 [6.4] cm). Three participants voluntarily withdrew after the second period, and 1 participant dropped out because of increased creatinine kinase levels caused by strenuous exercise before the start of the third period. Thus, 21 participants completed the study schedule to compare the pharmacokinetic parameters of lobeglitazone, and 22 participants completed the study of amlodipine. The geometric mean ratio (with 90% CIs) of Cmax,ss and AUCτ,ss for lobeglitazone administered concomitantly with amlodipine versus lobeglitazone administered alone was 1.01 (0.93-1.09) and 1.06 (0.92-1.23), respectively. The geometric mean ratio (with 90% CIs) of Cmax,ss and AUCτ,ss for amlodipine administered concomitantly with lobeglitazone versus amlodipine administered alone was 0.98 (0.94-1.02) and 1.00 (0.96-1.05). No serious drug-induced adverse events were reported in the study, and no clinically significant changes in vital signs, physical examination results, clinical laboratory results, or ECGs were noted., Implications: The coadministration of lobeglitazone and amlodipine did not affect the pharmacokinetics of lobeglitazone or amlodipine in these healthy male Korean subjects. ClinicalTrials.gov identifier: NCT01341392., (Copyright © 2015 Elsevier HS Journals, Inc. All rights reserved.)

Hydrophilic interaction liquid chromatography (HILIC) provides a feasible approach to effectively separate polar compounds in complex matrices. Herein, a simple, reproducible and efficient HILIC method was developed for the simultaneous determination of pioglitazone. HCl (PIO) and metformin HCl (MET) in rabbit plasma. High-purity silica column was used for rapid and efficient separation of these co-administered drugs. The chromatographic parameters were optimized for best separation. The proposed HILIC system provides high separation efficiency with good peak shape compared to reversed phase (RP) chromatography. Additionally, a simple isocratic elution mode with a mobile phase composed of a mixture of methanol and 10mM phosphate buffer (pH 3.0) (94:6, v/v) was used and the effluent was monitored at 230nm. The method was validated in accordance with the requirements of US-FDA guidelines and was found to behave efficiently for the intended purpose. The correlation coefficient of 0.9992 was obtained in the concentration ranges of 0.5-100μgmL(-1). The limits of detection (S/N=3) and quantification (S/N=10) were 0.16 and 0.5ngmL(-1), respectively. The retention times were 3.4 and 5.0min for PIO and MET, respectively. Plasma levels were successfully determined in rabbit with satisfactory precision and accuracy. In addition, the stability tests in rabbit plasma proved reliable stability under the experimental conditions. The developed HILIC method was applied successfully to study the pharmacokinetic behaviors of the studied analytes in rabbit plasma after a single oral dose containing PIO and MET., (Copyright © 2015 Elsevier B.V. All rights reserved.)

We report the in vitro release profile and comparative pharmacokinetics and biodistribution of a new peroxisome proliferator-activated receptor-γ agonist and cyclooxygenase inhibitor (Lyso-7) free or associated to poly(D,L-lactic acid) nanocapsules (NC) after intravenous administration in mice. Lyso-7 pertains to the class of insulin-sensitizing agents that shows potential beneficial effects in diabetes therapy. Monodispersed Lyso-7 NC with a mean diameter of 273 nm with high encapsulation efficiency (83%) were obtained. Lyso-7 dissolution rate was reduced (2.6-fold) upon loading in NC. The pharmacokinetic parameters were determined using a non-compartmental approach. In comparison with Lyso-7 in solution, the plasma-AUC increased 14-fold, the mean residence time 2.6-fold and the mean half-life (t1/2) 1.5-fold for Lyso-7-NC; the Lyso-7 plasma clearance, distribution volume and elimination rate were reduced 13, 10 and 1.4 fold, respectively, which indicates higher retention of encapsulated Lyso-7 in the blood compartment. Upon association with NC, organ exposure to Lyso-7 was higher in the heart (3.6-fold), lung (2.8-fold), spleen (2.3-fold), kidney (2-fold) and liver (1.8-fold) compared to Lyso-7 in solution. The analysis of whole data clearly indicates that body exposure to Lyso-7 was enhanced and the general toxicity reduced upon nanoencapsulation, allowing further evaluation of Lyso-7 in nonclinical and clinical studies., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Introduction: Type 2 diabetes is a complex disease with multiple defects, which generally requires a combination of several pharmacological approaches to reach glucose control targets. A unique fixed-dose combination combines a thiazolidinedione (pioglitazone) and a dipeptidyl peptidase-4 inhibitor (alogliptin)., Area Covered: An extensive literature search was performed to analyze the pharmacokinetics of pioglitazone and alogliptin when used separately and in combination as well as to summarize clinical and toxicological considerations about the combined therapy., Expert Opinion: Pioglitazone, a potent insulin sensitizer, and alogliptin, an incretin-based agent that potentiates post-meal insulin secretion and reduces glucagon secretion, have complementary mechanisms of action. The clinical efficacy of a combined therapy is superior to any single therapy in patients treated with diet or with metformin (with or without sulphonylurea). These two drugs can be administered once daily, with or without a meal. No clinically relevant pharmacokinetic interactions between the two agents have been described and the fixed-dose combination has shown bioequivalence with alogliptin and pioglitazone given separately. Combining alogliptin with pioglitazone does not alter the safety profile of each compound. Weight gain observed with pioglitazone may be limited with the addition of alogliptin. The concern of an increased risk of heart failure remains to be better investigated.

A new method for simultaneous determination of phentermine and topiramate by liquid chromatography/electrospray tandem mass spectrometry (LC/MS/MS) operated in positive and negative ionization switching modes was developed and validated. Protein precipitation with acetonitrile was selected for sample preparation. Analyses were performed on a liquid chromatography system employing a Kromasil 60-5CN column (2.1 mm × 100 mm, 5 μm) and an isocratic elution with mixed solution of acetonitrile-20mM ammonium formate containing 0.3% formic acid (40:60, v/v), at a flow rate of 0.35 mL/min. Doxazosin mesylate and pioglitazone were used as the internal standard (IS) respectively for quantification. The determination was carried out on an API 4000 triple-quadrupole mass spectrometer operated in multiple reaction monitoring (MRM) mode using the following transitions monitored simultaneously: positive m/z 150.0/91.0 for phentermine, m/z 452.1/344.3 for doxazosin, and negative m/z 338.3/77.9 for topiramate, m/z 355.0/41.9 for pioglitazone. The method was validated to be linear over the concentration range of 1-800 ng mL(-1) for phentermine, 1-1000 ng mL(-1) for topiramate. Within- and between-day accuracy and precision of the validated method at three different concentration levels were within the acceptable limits of <15% at all concentrations. Blood samples were collected into heparinized tubes before and after administration. The simple and robust LC/MS/MS method was successfully applied for the simultaneous determination of phentermine and topiramate in a pharmacokinetic study in healthy male Chinese volunteers., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Pioglitazone is currently undergoing clinical trials for treatment of Alzheimer's disease (AD). However, poor brain penetration remains an obstacle to development of the drug for such intended clinical uses. In this study, we demonstrate that the inhibition of P-glycoprotein (P-gp) significantly increases brain penetration of pioglitazone, whereas inhibition of breast cancer resistance protein (BCRP) has little effect. We also investigate the stereoselectivity of pioglitazone uptake in the brain. When mice were dosed with racemic pioglitazone, the concentration of (+)-pioglitazone was 46.6% higher than that of (-)-pioglitazone in brain tissue and 67.7% lower than that of (-)-pioglitazone in plasma. Dosing mice with pure (+)-pioglitazone led to a 76% increase in brain exposure levels compared to those from an equivalent dose of racemic pioglitazone. Pure (+)-pioglitazone was also shown to have comparable amyloid-lowering capabilities to the racemic pioglitazone in an in vitro AD model. These results suggest that P-gp may act as a stereoselective barrier to prevent pioglitazone entry into the brain. Dosing with (+)-pioglitazone instead of the racemic mixture may result in higher levels of brain exposure to pioglitazone, thus potentially improving the development of pioglitazone treatment of AD.