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Narcolepsy is a rare, chronic neurological disorder characterized by a dysregulated sleep-wake cycle, with core clinical features including excessive daytime sleepiness (EDS), cataplexy, hypnopompic/hypnagogic hallucinations, and sleep paralysis. Several treatment options are available for the symptomatic management of narcolepsy, but they have limitations. Comorbidities of narcolepsy further limit the treatment choices. Blocking of histamine 3 (H3) receptors has been demonstrated to be a viable approach for the management of symptoms of narcolepsy. Samelisant (SUVN-G3031) is a new H3 receptor inverse agonist. The efficacy, safety, tolerability, and pharmacokinetics of Samelisant in narcolepsy patients were evaluated in a phase 2, double-blind, placebo-controlled study (ClinicalTrials.gov identifier: NCT04072380). Patients diagnosed with narcolepsy according to the International Classification of Sleep Disorders criteria and having an Epworth Sleepiness Scale (ESS) score of ≥12 and a mean Maintenance of Wakefulness Test (MWT) time of <12 min across the 4 sessions at baseline were enrolled. The total study duration was up to 7 weeks, which included a screening period of 4 weeks, a treatment period of 2 weeks, and a safety follow-up 1 week after the last study drug administration. The primary efficacy measure was the change in total ESS score compared to placebo. Secondary and exploratory assessments included the Clinical Global Impression of Severity, MWT, Clinical Global Impression of Change, Patient Global Impression of Change and cataplexy rate. Safety assessments included monitoring adverse events (AEs) and laboratory assessments. Of the 426 patients screened, 190 were randomized. The safety and intention-to-treat population included 188 and 164 patients, respectively. A statistically significant treatment effect of Samelisant was observed on the primary endpoint, indicating improvements in EDS. The treatment's impact on EDS was also evident on the other patients' and clinicians' perspectives scales. The AEs reported in ≥5 % patients in any treatment groups were insomnia, abnormal dreams, nausea, and hot flush. Global phase 3 studies and long-term safety and efficacy assessments of Samelisant are planned to reaffirm the current findings., Competing Interests: Declaration of competing interest Ramakrishna Nirogi, Anil Shinde, Vinod Kumar Goyal, Jyothsna Ravula, Vijay Benade, Satish Jetta, Veera Raghava Chowdary Palacharla, Dhanunjay Kumar Dogiparti, Ilayaraja Kalaikadhiban, Renny Abraham, Santosh Kumar Pandey, Ramkumar Subramanian, Abdul Rasheed Mohammed, Pradeep Jayarajan, and Venkat Jasti are full-time employees of Suven Life Sciences Ltd., India. Richard K. Bogan, MD, FCCP, FAASM disclosure includes: Shareholder WaterMark Medical, Healthy Humming, LLC; Board of Directors: WaterMark Medical; Consultant to Jazz Pharmaceuticals, Harmony Biosciences, Avadel Pharmaceuticals, Takeda, Oventus, Axsome; Industry funded research for Avadel, Axsome, Bresotec, Bayer, Idorsia, Suven, Jazz, Balance, NLS, Vanda, Merck, Eisai, Philips, Fresca, Takeda, Liva Nova, Roche, Sanofi, Sommetrics, Noctrix, Oura. Richard Bogan did not receive compensation for developing this manuscript., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Purpose: SUVN-1105 is a novel formulation of abiraterone acetate which was developed to demonstrate improved bioavailability, compared to Zytiga and Yonsa, and to reduce the dose and eliminate the food effect. A Phase 1 study was conducted to assess the bioequivalence, food effect, and comparative pharmacokinetics of SUVN-1105 to Zytiga in healthy male subjects., Methods: The study comprised of 2 segments. Segment 1 was a single-center, 4-period crossover, open-label, fixed treatment sequence, single-dose study to evaluate the safety and pharmacokinetics of SUVN-1105 (N = 12 subjects per period). Segment 2 was a single-center, open-label, single-dose, randomized, 4-period, 4-treatment, 4-sequence crossover study to evaluate bioequivalence and comparative pharmacokinetics of SUVN-1105 against Zytiga (N = 44) under overnight fasted, modified fasted, and fed conditions., Results: Abiraterone exposures appeared to increase proportionately with SUVN-1105 dose (200 mg vs. 250 mg) in Segment 1. In Segment 2, abiraterone exposures of 250 mg SUVN-1105 in the fasted or fed conditions were higher than those of Zytiga 1000 mg in the overnight fasted conditions. Abiraterone exposures of 250 mg SUVN-1105 decreased in the fed conditions (64% and 29% decrease in C max and AUC, respectively) compared to overnight fasted conditions., Conclusions: The abiraterone exposures of 250 mg SUVN-1105 in the fasted or fed conditions fall within the abiraterone exposures of 1000 mg Zytiga in fasted and modified fasted conditions. Single doses of SUVN-1105 were safe and well-tolerated in healthy males both in the fasted and fed conditions., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Liquid chromatography and the tandem mass spectrometry method to quantitate SUVN-D4010 (Usmarapride) in human plasma and urine have been developed and fully validated in compliance with regulatory guidelines. The sample preparation technique is simple and rapid consisting of acetonitrile precipitation followed by dilution of supernatant with a compatible solvent. Chromatographic separation was achieved on an X-Bridge C 18 (2.1×50 mm, 3.5 µm) column using 0.1% v/v ammonium hydroxide and acetonitrile as mobile phase components, delivered at a flow rate of 0.75 mL min -1 . Electrospray Ionization technique in positive mode was used for mass spectrometric detection. Selective reaction monitoring (SRM) transitions of m/z 384.2 → 352.1 for SUVN-D4010 and m/z 388.2 → 356.1 for SUVN-D4010-d4 were used for quantitation. Calibration curves for SUVN-D4010 were linear across the concentration range of 0.3-300 ng mL -1 in human plasma and 5.00-5000 ng mL -1 in human urine. The method generated results with acceptable accuracy (± 9.0%), precision (%CV, ≤8.7), and mean extraction recovery (≥93.4%) with negligible matrix effect in both plasma and urine. SUVN-D4010 was found to be stable in human plasma and urine at the defined storage conditions. The validated method was successfully applied to quantitate SUVN-D4010 in human plasma and urine from a clinical first-in-human study conducted to evaluate its safety, tolerability, and pharmacokinetics in healthy adults., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Background: A LC-MS/MS method was validated for the quantification of SUVN-G3031, a novel H3 receptor inverse agonist in clinical development for the treatment of patients with narcolepsy, with and without cataplexy. Methodology: SUVN-G3031 was extracted from plasma following acetonitrile protein precipitation, separated by Ultra HPLC and quantified using positive ESI-MS/MS. Results: The method was linear across the range of 0.1-100 ng ml -1 in plasma. Results for intra and inter-day accuracy were from 99.8 to 104% and precision (%CV) was ≤10.6%. Conclusion: The method was applied to a first-in-human study in healthy volunteers. The method is precise, accurate and highly selective for the quantification of SUVN-G3031 in human plasma.

1. Determination of f m, CYP for a compound is critical to assess the potential risk of a drug candidate as a victim of DDI. Several compounds are identified as CYP2B6 substrates, but the f m, CYP2B6 values are not determined quantitatively. 2. Two methods of reaction phenotyping, the chemical inhibition method and metabolism in rCYP enzymes, were used to determine the relative contributions of the enzymes. Chemical inhibition method was also conducted in the presence of BSA (0.5% w/v). 3. The results confirm with the earlier studies concerning the identity of the CYP2B6 enzyme. The f m, CYP2B6 values for artemisinin, bupropion, clopidogrel, ketamine, selegiline, sertraline and ticlopidine were 0.24, 0.28, 0.15, 0.45, 0.46, 0.42 and 0.54, respectively, in HLM determined by chemical inhibition method. The f m, CYP2B6 values for artemisinin, bupropion, clopidogrel, ketamine, selegiline, sertraline and ticlopidine were 0.46, 0.17, 0.15, 0.60, 0.51, 0.66 and 0.77, respectively, in HLM determined by chemical inhibition method in the presence of BSA (0.5% w/v). 4. Bupropion metabolism is majorly mediated by CYP2C19 (0.41) with a minor contribution from CYP2B6 (0.16) in the presence of BSA. Ticlopidine is a time-dependent inhibitor of both CYP2B6 and CYP2C19 that can inhibit the bupropion metabolism by 50-60%.

Background: Skin is the target site to evaluate the pharmacokinetic parameters of topical applications. Sample preparation is one of the influential steps in the bioanalysis of drugs in the skin. Evaluation of dermatopharmacokinetics at preclinical stage is challenging due to lack of proper sample preparation method. There is a need for an efficient sample preparation procedure for quantification of drugs in the skin using LC-MS/MS., Results: The skin samples treated with collagenase followed by homogenization using a bead beater represents a best-fit method resulting in uniform homogenate for reproducible results., Conclusion: A new approach involving enzymatic treatment and mechanical homogenization techniques were evaluated for efficient sample preparation of skin samples in the bioanalysis.

1. Chemical inhibition is the widely used method in reaction phenotyping assays for estimation of specific enzyme contribution to a given metabolic pathway. The results from phenotyping assays depend on the selectivity of chemical inhibitor and the concentration of inhibitor used in the incubation. 2. The higher protein concentrations used in the in vitro phenotyping assays will impact the inhibitory potency of chemical inhibitors. The objective of the study is to evaluate comprehensively the selectivity of chemical inhibitors and to guide in selecting appropriate concentration of the chemical inhibitors to be used in the phenotyping assays based on unbound fractions. 3. Selectivity of chemical inhibitors against nine major CYP450 isoforms was determined in liver microsomes using standard probe substrates. The unbound fractions of the selective inhibitors were determined in human liver microsomes using high-throughput equilibrium dialysis. Combining unbound inhibitor concentrations that are required to inhibit the CYP450 activities by 90% and unbound fractions of the chemical inhibitors in liver microsomes appropriate total concentrations of the inhibitors to be used in the phenotyping assays were reported. 4. The findings suggest that non-specific binding of the chemical inhibitors need to be taken into account while selecting concentrations for phenotyping assays.

A high-performance liquid chromatography/positive ion electrospray tandem mass spectrometry method for the simultaneous quantification of lamivudine, stavudine and nevirapine was developed and validated in dried blood spot (DBS) cards. The analytes were separated using an isocratic mobile phase on a reverse phase column and analyzed by MS/MS in the MRM mode using the respective [M + H]⁺ ions, m/z 230-112 for lamivudine, m/z 225-127 for stavudine, m/z 267-226 for nevirapine, m/z 383-337 for zidovudine (IS). The lower limit of quantification was 1 ng/mL for both lamivudine and stavudine and 10 ng/mL for nevirapine. Acceptable precision and accuracy were obtained for concentrations over the standard curve range. The method was successfully applied to quantify them in a rat pharmacokinetic study in whole blood, plasma and DBS cards after a single oral co-administration at the dose of 10, 2 and 13 mg/kg for lamivudine, stavudine and nevirapine, respectively, to male Wistar rats. Following oral administration the pharmacokinetic results in all the matrices are in close agreement. Thus accomplishment of this method would facilitate the ease of collection of clinical samples on DBS cards for lamivudine, stavudine and nevirapine during human clinical trials and therapeutic drug monitoring., (Copyright © 2012 John Wiley & Sons, Ltd.)

A sensitive high-performance liquid chromatography-positive ion electrospray tandem mass spectrometry method was developed and validated for the quantification of ambrisentan in plasma. The analyte and the internal standard (armodafinil) were extracted from plasma by acetonitrile precipitation and they were separated on a reversed-phase C(18) column with a gradient program. The MS acquisition was performed with multiple reaction monitoring mode using the respective [M + H](+) ions, m/z 379-347 for ambrisentan and m/z 274-167 for the IS. The assay exhibited a linear dynamic range of 1-2000 ng/mL for ambrisentan in plasma. Acceptable precision (<10%) and accuracy (100 ± 8%) were obtained for concentrations over the standard curve range. The method was successfully applied to quantify ambrisentan concentrations in a rodent pharmacokinetic study after a single oral administration of ambrisentan at 2.5 mg/kg to rats. Following oral administration the maximum mean concentration in plasma (C(max) ; 1197 ± 179 ng/mL) was achieved at 1.0 ± 0.9 h (T(max) ), and the area under the curve (AUC) was 6013 ± 997 ng h/mL. Therefore, development of such a simple and sensitive method in rat plasma should translate into a method for ambrisentan in human plasma for clinical trials., (Copyright © 2012 John Wiley & Sons, Ltd.)