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A reverse phase high-performance liquid chromatography (HPLC) method has been developed for the quantification of a typical drug Dasatinib (DST) and its related impurities in pharmaceuticals. Kinetex C18 (4.6 × 150 mm, 5 μm) column was used in the chromatographic separations, using buffer (1.36 g of KH2PO4 in 1000 mL of water, pH = 7.8; adjusted with diluted KOH solution) with solvent as acetonitrile and mode of elution as the gradient. The flow rate is 0.9 mL/min, column oven temperature as 45°C and the overall gradient run time as 65 min. The developed method was found to produce symmetric and good separation between the process-related and degradation impurities. Method optimization is achieved with photodiode array at 305 nm over the concentration range of 0.5 mg/mL and degradation studies were carried out under acidic, alkaline, oxidative, photolytic and thermal conditions to demonstrate the stability indicating capability of the method. Two major impurities were found in forced degradation studies in the HPLC analysis, the unknown, acid degradants were enriched and isolated by preparative HPLC, then characterized through high-resolution mass spectrometry, nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy. The unknown acid degradation impurity was showing Exact Mass of 521.11, molecular formula C22H25Cl2N7O2S and its chemical name as 2-(5-chloro-6-(4-(2-hydroxyethyl) piperazin-1-yl)-2-methylpyrimidin-4-ylamino)-N-(2-chloro-6-methylphenyl) thiazole-5-carboxamide. Another impurity (oxidative degradant) found as known DST N-oxide Impurity-L and its chemical name as 4-(6-((5-((2-chloro-6-methylphenyl) carbamoyl) thiazol-2-yl) amino)-2-methylpyrimidin-4-yl)-1-(2-hydroxyethyl) piperazine 1-oxide. The analytical HPLC method was further validated as per ICH guidelines. [ABSTRACT FROM AUTHOR]

Many analytical methods are reported for simultaneous estimation of pharmaceutical dosages form. However, only a few are reproducible at an industrial scale. The proposed research aims to establish a technology transfer (TT) protocol between two laboratories (Lab-X, originator) with binary and (Lab-Y, receiver) with quaternary high-performance liquid chromatography (HPLC) system. Thus, utilizing reverse-phase HPLC (RP-HPLC), a robust, sensitive and repeatable analytical method has been developed, validated and TT between two laboratories for simultaneous estimation of Andrographolide (AG) and Paclitaxel (PTX). The method has been developed on a Phenomenex Luna C18 column (150 x 4.6, 5) sustained at 40°C and validated under the International Conference on Harmonisation (ICH) Q2 (R1) regulatory guideline and TT USP chapter 1224. The mobile phase consisted of MilliQ (pH = 3) and a combination of acetonitrile and methanol (1:1) in the ratio 50:50 with a flow rate of 0.45 mL/min, linear gradient elution in both labs. The AG and PTX were detected on the PDA detector at 224 and 227 nm wavelength with retention time of 4.5 ± 0.34 and 8.2 ± 0.02 min and limit of detection was found 0.028 ± 0.004 μg/mL, and 0.028 ± 0.0007 μg/mL, whereas limit of quantification as 0.086 ± 0.011 μg/mL and 0.088 ± 0.0014 μg/mL respectively in both labs. Throughout, this approach we have proved that proposed method is repeatable in both labs, and it can be used to quantify AG and PTX in developed pharmaceutical nano-formulations. [ABSTRACT FROM AUTHOR]

A new stability-indicating liquid chromatography method was developed for the quantification of empagliflozin and two synthetic impurities. The chromatographic conditions included Spherisorb® RP-18 column (150 × 4.6 mm, 5 μm) with a PDA detector, using acetonitrile and formic acid (pH 4.0) as mobile phase in gradient elution and flow-rate of 1.2 mL·min−1. The gradient increasing from 51 to 100% acetonitrile until 11.00 min, followed by decreasing the solvent from 100% to the initial ratio from 11.01 to 15.00 min. The method was validated according to International Council of Harmonization guidelines. The LOD and LOQ values for impurities A and B were 35 and 15 ng·mL−1, respectively, (for LOD) and 115 and 35 ng.mL−1, respectively (for LOQ). The method was linear in the range of 80–140, 115–1150 and 35–350 ng·mL−1 for EMPA, impurities A and B, respectively, and the correlation coefficient were > 0.999 in all situations, indicating the method good linearity. The developed method showed a good recovery for empagliflozin and added impurities. The method has proven to be precise, demonstrated values less than 2.0% to empagliflozin and 5.0% to synthetic impurities, robust and selective with no interference from other products in the determination of analytes. The in silico toxicity prediction suggested that the impurities do not present any toxicity risk for the parameters evaluated. [ABSTRACT FROM AUTHOR]

Firocoxib is a nonsteroidal anti-inflammatory drug. It provides control of postoperative pain and inflammation associated with soft tissue and orthopedic surgery in dogs, and control of pain and inflammation associated with osteoarthritis in horses. A high-speed stability-indicating reversed-phase high-performance liquid chromatography method was developed to determine firocoxib and its related substances in bulk batches of firocoxib drug substance. Firocoxib was dissolved in neat acetonitrile (ACN) and analyzed on a short HALO (fused-core) biphenyl column (30 × 4.6 mm i.d. 2.7-μm particle size) at flow rate of 2.5 mL/min. Column temperature was maintained at 50°C. Mobile phase A is composed of 0.1% of H3PO4 in water and mobile phase B is composed of ACN. Analytes were detected with UV detection at 240 nm and quantitated against an external reference standard. Firocoxib and its related compounds were adequately separated within 4 min by a gradient elution. The method was validated for specificity, linearity, accuracy, precision and robustness according to method validation guidelines described in The International Conference on Harmonization. The validation data demonstrated that this method is sensitive, accurate, robust, specific and stability-indicating. [ABSTRACT FROM AUTHOR]

Fangji Huangqi Decoction (FHD) is a classic prescription of traditional Chinese medicine which is recorded in "Jin Gui Yao Lue". The purpose of this study is to develop a method for simultaneous determination multicomponent in FHD. The separation of the 19 compounds that included calycosin, calycosin-7-O-β-D-glucoside, formononetin, ononin, methylnissolin, methylnissolin-3-O-glucoside, isomucronulatol, tetrandrine, fangchinoline, atractylenolide-I, atractylenolide-III, liquiritigenin, liquiritin, isomucronulatol-7-O-β-D-glucoside, astragaloside-I, astragaloside-II, astragaloside-III, astragaloside-IV and glycyrrhetinic acid were achieved by linear gradient elution. The 19 components were identified by comparing the chromatographic peaks with the reference compounds and were quantitatively analyzed by multiple reaction monitoring. This method was strict validated with recovery (96.10–101.70%), precision [relative standard deviation (RSD), 1.34–3.34%], stability (RSD, 1.49–3.80%) and repeatability (RSD, 1.60–3.49%), respectively. All the compounds showed good linearities (R 2 > 0.999). The limit of detection (LOD) and limit of quantitation (LOQ) for the 19 compounds were in the range of 0.03–0.27 μg/mL (LODs) and 0.05–1.23 μg/mL (LOQs). The correlation analysis indicated that astragalus flavonoids were negatively correlated with astragalosides, tetrandrine and their corresponding flavonoid glycosides, and atractylenolides were positively correlated with astragalosides and fangchinoline. This method proved to be reliable and effective, which would give a helpful basis for the quality control, pharmacological and pharmacokinetic of FHD. [ABSTRACT FROM AUTHOR]

Tecoma stans (Fam. Bignoniaceae) is also popularly known as yellow bells and yellow trumpet bush in vernacular terminology. Limited and variable data are available from the literature regarding the quantification of luteolin, apigenin and chrysoeriol, which are considered as the most active pharmacological active constituents. High-performance liquid chromatography–photodiode array detection has been developed for the determination of the bioactive flavonoids, luteolin, apigenin and chrysoeriol, from the methanolic extract of the leaves of T. stans. A column packed with a pentafluorophenyl-based stationary phase was used for the separation of the analytes under gradient elution. The detection wavelength was 345 nm. The validation of the method as per the International Council on Harmonisation (ICH) guidelines (ICH 2005) for linearity, accuracy and precision was investigated and found within limits specified by the ICH guidelines. The method was linear over with a good regression coefficient of more than 0.99. The limit of detection of the method was 0.68, 2.97 and 1.76 μg/mL for luteolin, apigenin and chrysoeriol, respectively. In conclusion, a reliable and reproducible method was devised that can be used for the estimation of the said components from T. stans. [ABSTRACT FROM AUTHOR]

The topical product with three active pharmaceutical ingredients (APIs), namely, esafoxolaner, eprinomectin and praziquantel has demonstrated its efficacy in the treatment of cats with mixed infections with ectoparasites and nematodes and cestodes. A reversed-phase high-performance liquid chromatography (RP-HPLC) method has been developed and validated for assay and determination of related substances peaks of three APIs including the assay of antioxidant butylated hydroxytoluene (BHT) in the finished product. Analytes were separated on a short Zorbax SB-C18 column (50 × 4.6 mm I.D. 5 μm particle size, pore size: 80 Å) with gradient elution at 40 °C column temperature. Analytes were detected at 245 nm for praziquantel, esafoxolaner, eprinomectin and their degradation products. BHT and eprinomectin degradation product 8a-oxo-B1a were detected at 280 nm. All analytes of interest were adequately separated within 40 min. The assay for praziquantel, esafoxolaner, eprinomectin and BHT was conducted against their corresponding external reference standards. The related substances peaks of each API were determined by peak area and relative response factor against total peak area of their corresponding API peak in sample solution. This method has been demonstrated to be accurate, robust, specific and stability indicating. [ABSTRACT FROM AUTHOR]

A high-performance liquid chromatograph with diode array detector was established for the simultaneous determination of five phenylethanoid glycosides in Syringa pubescens Turcz. The optimal chromatographic conditions were achieved on a Zorbax C18 column using gradient elution with 0.5% aqueous acetic acid and acetonitrile as the mobile phase at the flow rate of 1.0 mL/min. The detection wavelength was developed as follows: 0–10 min, 276 nm; 10–45 min, 332 nm. The validation of the method including linearity, precision, stability, accuracy, repeatability and recovery was tested. The chemometric analysis including hierarchical cluster analysis and principal component analysis was employed to investigate the similarity and difference of samples from different geographical origin. The results revealed that S. pubescens samples were divided into four clusters based on the phenylethanoid glycosides contents. Antioxidant activity of extract was measured using three different methods including α,α-diphenyl-β-picrylhydrazyl and 2,2-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) radical scavenging assays, and ferric reducing antioxidant power assay. Furthermore, different phenylethanoid glycosides exhibited different contribution to antioxidant capacities. This study provides a foundation for the quality evaluation and offers scientific data for the utilization of S. pubescens resources. [ABSTRACT FROM AUTHOR]

Nalbuphine was a semisynthetic opioid analgesic widely used in the treatment of both acute and chronic pain. We developed and validated a rapid, simple and sensitive method by ultra-performance liquid chromatography–tandem mass spectrometry (MS/MS) for the simultaneous quantitation of nalbuphine in human plasma, and we reported the pharmacokinetic features of patients during general anesthesia for abdominal surgery. Sample separation was achieved on a Kinetex Phenyl-Hexyl column (50 × 2.1 mm, 1.7 μm) after simple protein precipitation with acetonitrile. The mobile phase was composed of acetonitrile and 3 mM of ammonium acetate aqueous solution with 0.1% formic acid. Gradient elution was used in 4.5 min with a flow rate of 0.5 mL/min at 40°C. MS detection using AB Sciex QTRAP 5500 mass spectrometer was characterized by electrospray ionization for positive ions in multiple reaction monitoring mode. Quantitative ion pairs were m/z 358.4 → 340.1 for nalbuphine and m/z 340.0 → 268.3 for nalmefene, which were used as the internal standard (IS). The calibration curves showed good linearity (r 2>0.99) over concentration range of 0.1–500 ng/mL. The intra-and inter-batch precisions were within 10.67%, and accuracy ranged from 94.07 to 105.34%. The IS–normalized matrix factors were 1.02–1.03 with RSD% (≤5.82%). The recoveries ranged from 101.09 to 106.30%. In conclusion, a rapid, simple, sensitive and economical analytical method was developed and validated to detect the concentration in plasma samples obtained from patients receiving nalbuphine intravenous injection and was successfully applicated to human pharmacokinetic studies of nalbuphine. [ABSTRACT FROM AUTHOR]

This study uses a liquid chromatography-electrospray ionization–tandem mass spectrometry method to determine β -Sitosterol and Ferulic acid in Pygeum africanum extract. Chromatographic separation of the two analytes was performed on an ACQUITY UPLC H-Class system coupled with Xevo TQD mass spectrometer and HSS T3 C18 column (2.1 X 50 mm, 1.8 μm). Mobile phase A consisted of an aqueous solution of 0.1% formic acid (v/v), and mobile phase B was 0.1% formic acid (v/v) in methanol pumped through a gradient elution mode. Mass spectrometer parameters were optimized using an electrospray ionization source in the positive and negative ionization modes. The quantification of the two analytes was performed using multiple reaction monitoring transitions. The method was fully validated per (FDA) guidelines regarding linearity, accuracy, precision, carryover and selectivity. The proposed method was applied successfully to determine the two investigated compounds in commercially available pharmaceutical products. [ABSTRACT FROM AUTHOR]

In this work, two chromatographic methods are developed and validated for the determination of enrofloxacin and bromhexine (BRM) HCl in the presence of two of their specified impurities, ciprofloxacin and BRM impurity C. The suggested chromatographic methods included the use of thin layer chromatography (TLC-densitometry) and high-performance liquid chromatography (HPLC). In case of TLC-densitometry, good separation was achieved by using mobile phase of n.butanol:acetone:water:glacial acetic acid:triethylamine (10:3:1:0.5:0.5, by volume) on silica gel stationary phase at 254-nm detection. The developed HPLC method used BDS HYPERSIL C18 column with a mobile phase of water:acetonitrile:methanol:triflouroacetic acid. A linear gradient elution of 75–10%, 20–50% and 5–40% for water, acetonitrile and methanol, respectively, was applied in 13 min at a flow rate of 1.5 mL min−1. These methods were sufficient to separate the four substances simultaneously, and they are validated as per International Conference on Harmonization guidelines. [ABSTRACT FROM AUTHOR]

Y-99, a promising first-in-class diuretic, is a novel urea transporter inhibitor with oral diuretic activity. However, little is known about the pharmacokinetic profiles of Y-99 in experimental animals. In this study, a method of quantitative determination of Y-99 in rat plasma based on high-performance liquid chromatography–tandem mass spectrometry was developed and validated in selectivity, linearity, recovery and matrix effect, accuracy and precision, stability, carry-over and dilution integrity. Chromatographic separation was conducted on an ACQUITY BEH C18 column (2.1 mm × 50 mm, 1.7 μm) with gradient elution at a 0.3 mL/min flow rate after protein precipitation. Mass spectrometry was performed by a positive electrospray ionization mass spectrometer in multiple reaction monitoring mode. The method showed standard-compliant linearity (1–1,000 ng/mL, r  = 0.9991). The intra-day and inter-day accuracy (relative error < 11.2%) and precision (coefficient of variation <8.4%) were within acceptable criteria. The recovery and matrix effects were 97.3–110.7% and 103.7–107.5%, respectively. The stability, dilution integrity and carry-over of the method were also within the acceptable criteria. Pharmacokinetic profiles of Y-99 in rats were first investigated using this method, which was vital for developing novel diuretics without electrolyte imbalance targeting urea transporters. [ABSTRACT FROM AUTHOR]

HPLC-PDA, LC–MS/MS methods were developed for simultaneous determination of a group of oxidative stress biomarkers (OSBs); 2dA, 2dC, 2dU, 3NLT, 5HMU and 8OHdG in 10 simulated artificial body fluids. O-phosphoric acid and methanol composed mobile phases A and B for gradient elution in HPLC-PDA using ODS-2 column. Linearity obtained for 1.0×10−6–1.0×10−4M range. LODs were 1.73×10−6, 1.19×10−6, 2.59×10−6, 1.40×10−6, 2.21×10−6 and 4.07×10−6M for 2dU, 8OHdG, 2dA, 2dC, 5HMU and 3NLT, respectively. LOQs were 5.29×10−6, 4.02×10−6, 6.82×10−6, 4.02×10−6, 6.82×10−6 and 9.92×10−6M. About 10 mM aqueous ammonium acetate solution and methanol containing 0.1% (v/v) formic acid composed mobile phases A and B for gradient elution in LC–MS/MS. Linearity obtained for 1.0×10−8–1.0×10−6M range. LODs were 2.88×10−10, 1.01×10−8, 3.38×10−9, 1.36×10−7, 1.81×10−7 and 1.40×10−8M for 2dU, 8OHdG, 2dA, 2dC, 5HMU and 3NLT, respectively. LOQs were 9.37×10−10, 3.22×10−8, 1.91×10−8, 4.53×10−7, 5.90×10−7 and 2.18×10−8M. Both methods were validated using ICH Q2(R1) guideline. Specificity, linearity, range, accuracy, precision, reproducibility, LOD, LOQ and recovery were achieved. Chemometric analysis was performed on raw PDA and MS data to check their significance for discrimination of OSBs. Sets of single and triple quadrupole fragmentations were evaluated for principle component analysis. Chosen number of PCs successfully distinguished OSBs of interest. [ABSTRACT FROM AUTHOR]

A simple, rapid, precise and accurate stability indicating high-performance liquid chromatographic (HPLC) method was developed for simultaneous quantification of Ciprofloxacin (CIP) and Loteprednol (LOT) along with their forced degradation products using central composite design (CCD) approach. CCD was prepared with three independent variables in a gradient HPLC method. In gradient program (GP) the ratio of phosphate buffer in the mobile phase was 70%, 75%, 80%, 85% and 90%, the pH of phosphate buffer was 2.6, 2.8, 3.0, 3.2 and 3.4, flow rate was 0.8, 0.9, 1.0, 1.1 and 1.2 mL/min. Resolution, tailing factor (CIP) and tailing factor (LOT) were selected as response factor. The effective separation of LOT and CIP was achieved on Phenomenex EVO-C18 column (4.6 mm × 250 mm × 5 μm particle size) opting gradient mode of elution. The mobile phase composed of 10 mM Phosphate buffer pH 3.2 with ortho-phosphoric acid and the organic phase composed of mixture of acetonitrile and methanol in 50:50% v/v with flow rate of 1 mL/min and diode array detection at 258 nm. The optimized variables found were flow rate of 1.0 mL/min, ratio of phosphate buffer in GP 80% at pH 3.0. The method was validated as per ICH guidelines and applied for analysis of stability samples. [ABSTRACT FROM AUTHOR]

Arbutin, niacinamide and 3-O-ethyl ascorbic acid (a new generation of vitamin C derivatives) are compounds that have a whitening effect on skin and are widely used in whitening cream products wherein parabens such as methyl paraben, ethyl paraben, propyl paraben and butyl paraben are also often added as preservatives. This study aims to develop a validated high-performance liquid chromatography (HPLC) method that can be used to determine arbutin, niacinamide and 3-O-ethyl ascorbic acid simultaneously in whitening cream products without interference from the parabens. The optimum conditions for the HPLC system were obtained using ODS-3 RP-C18 Inertsil column, mobile phase consisting of a mixture of aquabides, methanol and acetonitrile with gradient elution mode. Detection was carried out using a UV detector at 220 nm. Validation studies demonstrated a good linearity for all analytes over each range concentration with a correlation coefficient >0.999 and Vx0 < 2%. The accuracy test also met the requirements with the recoveries being 96.93–99.55%, 98.60–99.73% and 97.88–100.63% for arbutin, niacinamide and 3-O-ethyl ascorbic acid, respectively. Intra-day and inter-day precision test gave a relative standard deviation (% RSD) of <2% along with a HorRat value of <2 for all analytes. The results of this study indicate that the developed HPLC method has a good selectivity, linearity, accuracy and precision. Due to its simplicity, the method can be used to analyze arbutin, niacinamide and 3-O-ethyl ascorbic acid in the presence of parabens in whitening cream products simultaneously. [ABSTRACT FROM AUTHOR]

A sensitive, simple, rapid and robust LC–MS/MS method was developed for the determination of potential genotoxic impurities OPDA HCl (orthophenylene diamine dihydrochloride), bromo OTBN (4'-bromomethyl-2-cyanobiphenyl), dibromo (4'(dibromomethyl)[1,1′-biphenyl]-2-carbonitrile) in Telmisartan by using ESI-MS/MS Technic; the study was performed with gradient elution (time/% mobile phase B: 0/10, 3/10, 30/80, 35/80, 36/10, 40/10). The mobile phase consisted of a mixture of formic acid, methanol and acetonitrile. The buffer was degassed before running at a flow rate of 1.0 mL/min. The column temperature was at 40°C. The 20 μL volume of sample was injected per run and peaks were detected using DAD detector. The LC-ESI/MS/MS studies were carried out on Ultivo Triple Quadrupole LC/MS/MS (Agilent, USA) G6470A mass spectrometer, ion source voltage 3500 V, de clustering potential 40 V, entrance potential 10 V, with the nebulizer gas as nitrogen at 45 psi. The LC part consisted of Agilent 1260 series HPLC system with binary gradient pump with a degasser and an auto sampler. Inert sustain AQ-C18, 250 × 4.6 mm, 5-μm particle size was used for chromatographic separation. Developed method is validated as per ICH guidelines and found to be linear, accurate, specific, selective, precise and robust. Test solution was found to be stable up to 48 h. This method can be successfully applied for the determination of genotoxic impurities in Telmisarta for routine analysis and stability assessment. [ABSTRACT FROM AUTHOR]

The feasibility of taking the ratio of 6β-hydroxycortisol (6β-OHCOR) to cortisol (COR) in plasma as a biomarker to reflect CYP3A4 activity needs to be verified, but the low concentration of 6β-OHCOR which is an endogenous substance in plasma presents a challenge for determination. In this study, a Liquid chromatography with tandem mass spectrometry (LC–MS/MS) method was established to simultaneously quantify the COR and 6β-OHCOR in plasma with COR-d4 and 6β-OHCOR-d4 as internal standards (ISs). Plasma samples were treated by protein precipitation using acetonitrile. Separation with a gradient elution within 5 min was achieved on C18+ column utilizing 5 mM ammonium formate and methanol. An API 4,000 MS in multiple reaction monitoring mode with transitions of 407.1 → 361.1 and 423.1 → 347.1 was utilized. Albumin solution was used as a surrogate matrix, with good linearities over the concentration of 1.20–300 ng/mL for COR and 0.0400–10.0 ng/mL for 6β-OHCOR. The precisions for intrarun and interrun were < 6.8%, and the accuracy was fell in the interval of −5.2 to 3.5%. Matrix effect was not found. Recovery was close to 100.0%. Stability was confirmed under the storage and processing conditions. The validated method was applied to evaluate the inhibitory effect of voriconazole to CYP3A by the ratio of 6β-OHCOR to COR. [ABSTRACT FROM AUTHOR]

Ivermectin is a potent semi-synthetic antiparasitic drug used in veterinary medicine. A reversed-phase high performance liquid chromatography (HPLC) method has been developed and validated for the identification and assay of Ivermectin, including the identification and estimation of its related impurities in an oral paste. Analytes were separated using a gradient elution at a flow rate of 1.5 mL/min on a Zorbax Extend-C18 column (150 mm × 4.6 mm i.d. 3.5-μm particle size) maintained at 30 °C. The mobile phase was composed of water as mobile-phase A and acetonitrile/methanol (85/15, v/v) as mobile-phase B. Ultraviolet detection at 245 nm was employed to monitor the analytes. Limit of quantitation (LOQ) and limit of detection (LOD) of the method are 0.6 and 0.2 μg/mL, respectively. The validation results demonstrated excellent linearity of the method in the range of 0.1–150% of the analytical concentration (0.6 mg/mL) of the method. The stability-indicating capability of the method has been demonstrated by adequately separating the degradation products from the stress degraded samples of the oral paste as per method validation requirements prescribed in the current International Council for Harmonisation guidelines. [ABSTRACT FROM AUTHOR]

Chirayata—the whole dried plant of Swertia chirayita— is an important traditional drug of Indian System of Medicines. A novel reverse-phase high performance liquid chromatography (RP-HPLC) method has been developed for the simultaneous determination and quantification of amaroswerin, amarogentin and andrographolide in a herbal drug "Chirayata, " which is oftenly adulterated/substituted with herbal drug Kalmegh. The developed method is in accordance with International Council for Harmonization guidelines and is simple, precise, accurate, rapid, reproducible and specific to determine amarogentin, amaroswerin and andrographolide. Reverse-phase column (Water's X-bridge C18, 5 μm, 4.6 mm × 250 mm) with high resolution for all marker compounds was used with binary gradient elution (methanol:water) with a flow rate of 1 mL/min and detection at 235 nm. The developed method showed good linearity (R 2 > 0.999) in a relatively wider range of concentration 2.968–95.00 ppm for amarogentin, amaroswerin and 5.625–180 ppm for andrographolide. The method is important for quality control analysis of drug Chirayata. [ABSTRACT FROM AUTHOR]

A ultraperformance liquid chromatography–tandem mass spectrometry method has been developed to determine dihydrocodeine (DHC) and dihydromorphine (DHM) in human plasma using dihydrocodeine-d6 and desomorphine as internal standards (IS). Acetonitrile–water–ammonium format was used as the mobile phase, in gradient elution on a C18 column. The concentration of DHC and DHM was determined in the positive ionization mode of mass spectrometry. The total chromatogram run time was 3.2 min, and the linear ranges of DHC and DHM were 1.000–400.0 ng/mL and 0.050–20.00 ng/mL, respectively. The method was fully validated concerning precision, accuracy, selectivity, linearity, recovery, stability and matrix effect. The method had been successfully applied to the bioequivalence test. In addition, we found that a high-fat diet impacts the Tmax and t 1/2 of DHC. [ABSTRACT FROM AUTHOR]

Delmopinol hydrochloride is widely used as an active ingredient (AI) in many human oral hygiene products. To the best of our knowledge (via literature search), there is no stability-indicating liquid chromatography method available in the public domain for assay and estimation of related substances of Delmopinol hydrochloride. A fast stability-indicating Reversed-Phase Ultra High-Performance Liquid Chromatography (RP-UHPLC) method has been developed and validated for identification, assay and estimation of related substances in commercial bulk batches of this AI. The major peak of the AI and its related compounds are adequately separated in 6 min by a gradient elution on a hybrid silica-based C18 column (Waters Acquity UPLC® BEH C18, 50mm × 2.1 mm I.D. 1.7 μm particle size) maintained at 50°C. Mobile phase-A is composed of aqueous 10 mM NH4OH and mobile phase-B is ACN. The AI and its related compounds are detected with UV detection at 220 nm and quantitated by an external Delmopinol hydrochloride reference standard. The quantitation limit of the method is 0.1% of the target analytical concentration. This UHPLC method is fast and green and has been demonstrated to be specific, accurate, linear, precise, sensitive and robust as per ICH guidelines. [ABSTRACT FROM AUTHOR]

A reversed-phase high-performance liquid chromatography (RP-HPLC) method has been developed and validated for the identification and assay of Ivermectin, including the identification and estimation of its process-related impurities and degradation products in bulk drug substance of Ivermectin. Analytes were separated on a HALO C18 column (100 mm × 4.6 mm I.D. 2.7 μm particle size) maintained at 40 °C (column temperature) with gradient elution. All analytes of interests were adequately separated within 25 min. All degradation products, process-related impurities and assay were monitored by ultraviolet detection at 254 nm. The new HPLC method described here successfully separated an isomer peak of the active pharmaceutical ingredient (API) from the major API peak. This newly separated isomer peak is around 1.2 to 1.5% (peak area) in typical API samples, and coelutes with the major API peak by all current HPLC methods. Quantitation limit of the HPLC method is 0.1% of target analytical concentration (~1.0 μg/mL). This method has been demonstrated to be accurate, robust, significantly higher degree of selectivity compared to the HPLC methods of Ivermectin drug substance reported in the literature and in the compendial HPLC methods prescribed in the current USA and European Pharmacopeia. [ABSTRACT FROM AUTHOR]

Fosamprenavir calcium is a protease inhibitor widely used in the treatment and prevention of human immunodeficiency virus and acquired immunodeficiency syndrome. This protease inhibitor serves as a prodrug of amprenavir, offering better oral bioavailability. Although this drug was approved by the FDA in 2003, there are few methods established for quantifying the stability for quality control analysis of fosamprenavir-coated tablets. The purpose of the study was to develop and validate a method for determining the stability of fosamprenavir-coated tablets (Telzir®) that may be applied by any quality control laboratory. Chromatographic separation was performed using a Vertical RP-18 column programmed to run a gradient elution with sodium acetate buffer and acetonitrile. Flow rate was 1.2 mL min−1 for a total run time of 15 min. Ultraviolet detection was set at 264 nm and the use of a photodiode array detector in scan mode allowed selectivity confirmation by peak purity evaluation. The analyte peak was found to be adequately separated from degradation products generated during forced degradation studies. Thus, the proposed method was found to accurately indicate stability and was sufficient for routine quantitative analysis of fosamprenavir in coated tablets without interference from major degradation products and excipients. [ABSTRACT FROM AUTHOR]

A validated RP-HPLC method was developed for the estimation of paracetamol, caffeine, metoclopramide and ergotamine simultaneously in bulk and pharmaceutical formulation. The method was extended for the determination of two paracetamol genotoxic and nephrotoxic impurities and degradation products namely p -aminophenol and 4-chloroacetanilide. Separation was done on octadecyl column (15 cm × 2.1 mm, 5 μm). Gradient elution was performed using mobile phase consisting of acetonitrile and water (pH 3) in ratio of (20: 80, v/v) for the first 3 min, (50: 50, v/v) for the next 4.5 min, then (20: 80, v/v) for the final 2.5 min. The flow rate was 0.7 mL/min throughout the run which took 10 min. UV detection was done at 230 nm. The proposed method agreed with ICH guidelines of method validation. The suggested method was applied for the estimation of the proposed drugs in their dosage form. Statistical comparison was done between the results obtained from the suggested method and those obtained from reported HPLC method. The proposed method is more beneficial than the published one because of having higher sensitivity and selectivity as it allows the detection of the proposed drugs in lower concentrations in the presence of paracetamol toxic impurities, p -aminophenol and 4-chloroacetanilide. [ABSTRACT FROM AUTHOR]

Fangji Huangqi Decoction is composed of Stephaniae Tetrandrae Radix, Astragli Radix, Atractylodis Macrocephalae Rhizoma and Glycyrrhizae Radix Et Rhizoma. It is a classic traditional Chinese medicine formula for the treatment of chronic glomerulonephritis in China. However, its pharmacokinetic characteristics in vivo are still unclear. In this study, a method for quantifying fangchinoline, tetrandrine and calycosin-7-O-β-D-glucoside, the main active constituents of Fangji Huangqi Decoction, in rat plasma by using ultrahigh-performance liquid chromatography–tandem mass spectrometry technique was developed. Plasma samples were processed with a deproteinization procedure using acetonitrile, followed by chromatographic separation on a Shim-pack XR-ODS C18 column using gradient elution of 0.1% aqueous formic acid and acetonitrile at 0.4 mL/min. The analytes and internal standard, diphenhydramine hydrochloride, were detected using positive electrospray ionization in multiple reactions monitoring mode. The optimized mass transition ion-pairs (m / z) were 609.3/367.3 for fangchinoline, 623.3/174.3 for tetrandrine, 447.2/285.1 for calycosin-7-O-β-D-glucoside and 256.2/167.1 for diphenhydramine hydrochloride, respectively. The developed method was validated for intraday and interday precision and accuracy whose values fell in the acceptable limits. Recovery efficiency of all the analytes was found to be >90.5%. Matrix effect was found to be negligible. Stability results showed that the analytes were stable under all conditions. The validated method was successfully used for studying the pharmacokinetics of the three compounds in rat plasma after oral administration of Fangji Huangqi Decoction. [ABSTRACT FROM AUTHOR]

We developed a new on-line method of ultra-performance liquid chromatography coupled with biochemical detection (UHPLC-BCD) to screen acetylcholinesterase (AChE) inhibitors in complex matrixes. Chromatography separation was performed using an Xtimate UHPLC C18 column (100 mm × 2.1 mm, 1.8 μm) and a gradient elution with methanol–0.1% formic acid at a flow rate of 0.08 mL/min. The BCD was based on a colorimetric method using Ellman's reagent, and the detection wavelength was at 405 nm. Galanthamine was used as a positive reference to validate the methodology. The detection and quantitation limits of the UHPLC-BCD method were 0.018 and 0.060 μg, respectively. A functional equation was generated in terms of the negative peak area (X) and galanthamine concentration (Y, μg/mL). The regression equation was Y = 0.0028X2 + 0.4574X + 50.7776, R 2 = 0.9993. UHPLC-fourier-transform mass spectrometry detection results revealed that five alkaloids showed obvious AChE inhibitory activities including coptisin, epiberberine, jatrorrhizine, berberine and palmatine. The relative AChE inhibitory activities of jatrorrhizine, berberine and palmatine in the Coptidis Rhizoma sample were equal to that of 257.0, 2355 and 283.9 μg/mL of galanthamine, respectively. This work demonstrated that the UHPLC-BCD method was convenient and feasible, and could be widely used for the screening and activity evaluation of the bioactive components in the complex extracts. [ABSTRACT FROM AUTHOR]

An efficient and rapid liquid chromatographic method was developed for the separation of carotenoids and their geometrical isomers in tomato products using a core C30 column of 2.6 μm particles with gradient elution of tert-butyl-methyl-ether in 2% water in methanol. Excellent separation of the major carotenoids such as lycopene, β-carotene and lutein as well as their geometrical isomers and oxygen-containing derivatives with resolution factors ranging between 0.78 and 4.0 and selectivity of 1.01–1.63 was achieved. Validation of the developed method met the acceptance criteria concerning linearity, recovery, precision and limit of detection and quantification. Calibrations were linear with correlation coefficient (R2) values between 0.9966 and 0.9999. The limit of detection and quantification values were found to be 0.008 and 0.017 and 0.029 and 0.056 μg/mL, respectively. Recovery of 94.3–99.9%, intraday precision of 1.81–4.45% and interday precision of 3.13–6.86% were obtained. The hyphenation of liquid chromatography with diode-array and mass spectrometry was helpful in the identification of the separated carotenoids particularly the unusual di-hydroxy cyclolycopene adduct and di-methoxy lycopene determined for the first time in tomato products. Commercially available kinds of tomato juice and ketchup were evaluated based on their carotenoid content. [ABSTRACT FROM AUTHOR]

Qilong capsule (QLC) is a well-known Traditional Chinese Medicine, and it has a long history for the treatment of ischemic stroke. Its major ingredients are saponins, such as paeoniflorin, amygdalin and calycosin-7-glucoside, contributing to vasodilation function. In this study, a simple, rapid and sensitive high-performance liquid chromatography-tandem mass spectrometry method was developed to determine three bioactive ingredients in rat plasma after oral administration of QLC. A simple acetonitrile precipitation method was introduced during the sample preparation. Chromatographic separation was performed on a Shiseido CAPCELL PAC MGIII-C18 column using a gradient elution with acetonitrile and water (0.1% formic acid) as a mobile phase, and the chromatographic separation was 5 min. The methodological evaluation showed that this method had a high sensitivity (the lower limit of quantification was 1 ng/mL for calycosin-7-glucoside, 5 ng/mL for paeoniflorin, 5 ng/mL for amygdalin), satisfactory accuracy (relative error ≤ ±15%) and precision (relative standard deviation ≤15%). Then, the analytical method was applied to the pharmacokinetic study in rats following oral administration of the extracts in QLC. Meanwhile, the pharmacokinetic parameters of complex system in QLC were analyzed and the potential interaction between ingredients was explored. The present quantification method and pharmacokinetic study will provide a meaningful reference for the formulas research of QLC in the treatment of ischemic stroke. Highlight A simple, rapid and sensitive HPLC–MS/MS analytical method was developed for the simultaneous determination of three ingredients in rat plasma after oral administration of QLC. A simple acetonitrile precipitation method was introduced to extract three biomedical ingredients during the plasma sample preparation. The pharmacokinetic results revealed the pharmacological active substances, identified internal variation rules and provided a meaningful reference for the formulas research of QLC in the treatment of ischemic stroke. [ABSTRACT FROM AUTHOR]

Objective To establish an ultra-high performance liquid chromatography (UPLC) method for simultaneous determination of umbelliferonel, nodakenin, psoralen, xanthotoxin and bergapten contents in Peucedanum decursivum Radix. Methods The analysis was achieved on a Symmetry®C18 column (4.6 mm × 250 mm, 5 μm), with acetonitrile and water as the mobile phase in gradient elution mode. The column temperature was maintained at 30°C, with flow rate 1.0 mL·min−1. The injection volume of sample was 10 μL. The ultraviolet detection wavelength was set at the maximum absorption wavelength 325 nm for umbelliferonel and nodakenin, 259 nm for psoralen, xanthotoxin and bergapten, respectively. Results The five kinds of coumarins in Peucedanum decursivum Radix were separated well and the linear relation was obtained (R 2 ≥ 0.9998). The average recoveries were 101.31, 105.27, 90.85, 106.42 and 90.19%, respectively, with Relative standard deviation (RSD) 3.07, 3.17, 1.62, 2.53 and 4.54%, respectively. Conclusions The established method was accurate and feasible, which could be used as the basis of quality control of Peucedanum decursivum Radix. [ABSTRACT FROM AUTHOR]

In the present study, two new methods were developed and validated for the determination of rilmenidine in bulk and pharmaceutical preparation. Both methods are based on a derivatization reaction using 4-chloro-7-nitro-1,2,3-benzoxadiazole (NBD-Cl) as a fluorogenic substance. The drug reagent derivatives were formed by the reaction of rilmenidine with NBD-Cl at pH 9.0 at 70°C for 40 min. The reaction mixtures were analyzed by spectrofluorimetry in the first method and high performance liquid chromatography (HPLC) in the second method. Derivatives were determined at λex 493 nm and at λem 536 nm in the spectrofluorimetric method. The separation was performed place on a Phenomenex, C18 column (250 × 4.6 mm, 5 μm i.d) using a mobile phase comprising 0.2% formic acid and acetonitrile gradient elution mode in the HPLC method. Analytes were detected by a fluorescence detector at the same wavelength. The methods were validated for limit of quantitation, linearity, robustness, recovery, limit of detection, precision and accuracy. Calibration curves for the first and second methods were found to be linear in the range of 2.0–12.0 and 250–2000 ng/mL, respectively. Detection limits for the spectrofluorimetric and HPLC methods were calculated as 0.16 and 18.28 ng/mL, respectively. The validated methods were applied successfully to the determination of rilmenidine in bulk and pharmaceutical preparation. [ABSTRACT FROM AUTHOR]

A sensitive high-performance liquid chromatography–tandem mass spectrometry method was established for the simultaneous determination of sildenafil and N -desmethyl sildenafil in human plasma. The protein precipitation was used for extraction and the gradient elution of the mobile phase A of water (containing 0.01% formic acid) and the mobile phase B of acetonitrile, and methanol (V:V = 1:1, containing 0.01% formic acid) was used for chromatographic separation on a C18 column. Quantification was performed by multiple reaction monitoring mode to monitor the precursor-to-product ion transitions of m/z 475.4 →  m/z 283.3 for sildenafil, m/z 461.4 →  m/z 283.2 for N -desmethyl sildenafil, m/z 483.3 →  m/z 108.1 for sildenafil-d8 (IS) and m/z 469.2 →  m/z 283.3 for N -desmethyl sildenafil-d8 (IS) at the positive ionization mode. The intra- and inter-day relative standard deviations were less than 6.8% and 4.1% for sildenafil and N -desmethyl sildenafil, respectively. Accuracy at four levels ranged from 93.1% to 115.9% for sildenafil and 95.6% to 112.5% for N -desmethyl sildenafil. The present method was sensitive and reliable for simultaneous quantification of sildenafil and its active metabolite and was successfully applied to a pharmacokinetic study of an oral low dose of sildenafil in Chinese healthy volunteers. [ABSTRACT FROM AUTHOR]

A selective RP-HPLC method for separation and determination of potential-related impurities (process related and degradants) of Ibrutinib drug substance has been developed and validated. The separation was accomplished on a X-Bridge C18, (150 x 4.6 mm, 3.5 μm) column connected to a photodiode array detector using 10 mM potassium dihydrogen phosphate with 0.025% of trifluoroacetic acid (pH ~ 5.5 adjusted with KOH solution) and acetonitrile in a ratio of 85:15 respectively as mobile phase A, and 10 mM potassium dihydrogen phosphate with 0.07% of trifluoroacetic acid (pH ~ 5.5 adjusted with KOH solution) and acetonitrile in a ratio of 30:70 respectively as mobile phase B, under gradient elution. The flow rate and detection wavelength were 1.0 mL/min and 220 nm, respectively. Quality by design approach using design expert software was strategically designed to optimize the critical chromatographic parameters like column temperature, flow rate and mobile phase B, pH variation in the mobile phase to achieve the separation of process impurities and thermal degradants. Two unknown impurities found in IBT thermal stability condition at more than 0.1% in HPLC analysis were enriched and isolated by preparative HPLC and structure was confirmed by 1H NMR, 13C NMR, mass spectroscopy and FT-IR spectroscopy. This method can be used for the quality control of both drug substance and drug product. The performance of the method was validated according to the International Conference on Harmonization guidelines for specificity, limit of detection, limit of quantification, linearity, accuracy, precision, ruggedness and robustness. [ABSTRACT FROM AUTHOR]

Objective This study aimed to establish an ion chromatography for the simultaneous determination of nitrite and azide ions in valsartan. Methods Dionex IonpacAG18 (4 × 50 mm2) and Dionex IonpacAS18 (4 × 250 mm2) were used as the 2D guard column and analytical column, respectively. Dionex AMGTMC18 (4 × 30 mm2) was used as a 1D pre-separation column and Dionex UTAC-ULP1 as the concentration column. KOH solution generated by an online eluent generator (EG) was used as the 2D mobile phase, and gradient elution was performed at 1 mL/min. Water and acetonitrile were used as 1D mobile phase, and gradient elution was performed at 0.5 mL/min. Suppressed conductivity detector (suppressor, ASRS 300 4 mm) was used for detection. The column temperature was 30°C, while that of the detector was 35°C. Results This method showed satisfactory reproducibility and recovery. The linear range and the correlation coefficient for both nitrite and azide ions were 0.01–0.2 mg/L and 0.9998, respectively. However, the recovery rate was 85–115% for nitrite and 90–110% for azide ions. Conclusion This method was suitable for the simultaneous determination of nitrite and azide ions in valsartan and other sartan drugs. [ABSTRACT FROM AUTHOR]

Objective Sinomenii Caulis (QingFengTeng) and Ramulus Cinnamomi (GuiZhi) are traditional Chinese drugs that have been used for anti-inflammation. In this study, the team plans to find out the material basis of a Chinese herb combination composed of the two herbs with different ratios. Methods The extracts of the herbal compound with various ratios obtained from ethanol extraction were analyzed by ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS) and gas chromatography coupled mass spectrometry to identify the basic chemical compounds. Simultaneously, the contents of the eight main components (sinomenine, magnoflorine, laurifoline, dauricine, coumarin, cinnamyl alcohol, cinnamic acid and cinnamaldehyde) from herb formula were determined by gradient elution by high-performance liquid chromatography. Furthermore, the content of sinomenine and cinnamaldehyde were determined by isocratic elution, respectively. Results Eighteen compounds in the herb formula were identified by UHPLC-Q-TOF-MS. The components in the GuiZhi are mostly volatile oils and the kinds of compounds isolated from the formula in the ratio of 4:1 were the most. Wherein eight compounds were identified as the main detection targets in the content determination. Conclusion The extraction rate of sinomenine in QingFengTeng was related to the proportion of GuiZhi in the drug pairs. Synchronously, the addition of sinomenine in different proportions also had some influence on the extraction of cinnamaldehyde in GuiZhi. Furthermore, the series of methods was successfully applied to the simultaneous determination of chemical compounds in different samples of QingFengTeng–GuiZhi decoction. [ABSTRACT FROM AUTHOR]

Vancomycin and teicoplanin are glycopeptide antibacterials that inhibit the bacteria cell wall synthesis showing activity against gram-positive bacteria. Development of the sensitive method is of great importance for quality control of these drugs that are fermentation products. Modification of the fermentation conditions could cause the differences in the relative amount of the total substance or component, as it is the case with teicoplanin. The main objective of this study was development of the sensitive and effective ultra high performance liquid chromatography - tandem mass sprectrometry (UHPLC-MS/MS) method for simultaneous quantification of vancomycin, all six subcomponents of teicoplanin, and its pharmacopoeial impurity A in pharmaceutical forms. The scientific-based Quality by Design approach was implemented in the MS and UHPLC method development. Detection and quantification of analytes were carried out in positive electrospray ion mode by multiple reaction monitoring. Capillary voltage, cone voltage and collision energy were optimized by implementing experimental design methodology and optimal values for each fragment ion were obtained by performing experiments according to 'Rechtschaffen' design matrix. An ACQUITY CSH Phenyl-hexyl (2.1 × 50 mm, particle size 1.7 μm) column was chosen for the separation under the gradient elution mode with the mobile phase consisted of 0.1% formic acid in water (mobile phase A) and acetonitrile (mobile phase B). Optimal gradient elution parameters were achieved by applying 'Rechtschaffen' design too. Method operable design regions were constructed for investigated MS and chromatographic parameters. The method was fully validated, and its applicability was confirmed throughout the ability to follow the behavior of vancomycin and teicoplanin under stress conditions. [ABSTRACT FROM AUTHOR]

The stability and exposure of toxin-related catabolites in system circulation contributes to the evaluation of the stability, targeted delivery and off-target toxicity for antibody–drug conjugates (ADC) at different stages during drug development. In this study, simple and rapid liquid chromatography–tandem mass spectrometry (LC–MS/MS) methods for determination catabolites of Mertansine (DM1), MCC-DM1 and Lys-MCC-DM1 in cynomolgus serum have been developed. The serum samples are processed by protein precipitation. The LC–MS/MS methods are applied on a Phenomenex C8 column (50 × 2.0 mm, 5 μm) with gradient elution with water–formic acid 0.1% (A) and acetonitrile-formic acid 0.1% (B) at a flow rate of 0.5 mL/min. The analytical run time is only 4.0 min and the calibration ranges of the standard curve are 0.500–200 ng/mL for DM1, 1.00–500 ng/mL for MCC-DM1 and 2.00–1000 ng/mL for Lys-MCC-DM1. Intra- and inter-day precision of low, middle and high quality controls was <15%, and accuracy was 99.2–110.9%. The methods were successfully applied to evaluate three catabolites of novel ADCs with N-succinimidyl-4-(N-maleimidomethyl)-cyclohexane-1-carboxylate linker in vitro and in vivo studies. [ABSTRACT FROM AUTHOR]

For the quantification of flurbiprofen in rat plasma, a simple UPLC-MS/MS method with high sensitivity and short retention time for flurbiprofen was developed and validated using specific parameters. Etodolac was used as internal standard. The transitions (precursor to the product) of flurbiprofen and internal standard were obtained using the electrospray ionization in the negative ion multiple reaction monitoring mode, 243.2 → 199.2, 286.2 → 212.1, respectively. For chromatographic separation, C18 column was used for the stationary phase and gradient elution was used for the mobile phase. This mobile phase consisted of a methanol (A) and a 5 mM ammonium formate solution (B), which varied at a flow rate of 0.4 mL/min. For flurbiprofen, LLOQ was determined as 5 ng/mL. Quantification of flurbiprofen in the rat plasma with a linear calibration curve of 5–5000 ng/mL (r > 0.9991 for plasma) is possible with a retention time of 1.89 min. The total analysis time of the method was 3 min. The proposed method was validated. The intraday and inter-day precision (RSD%) and accuracy (RE%) were within 10% in all cases for flurbiprofen. The stability of flurbiprofen was evaluated under conditions such as short-term, long-term, autosampler and freeze/thaw. After method validation, flurbiprofen was succesfully quantified in real rat plasma samples. [ABSTRACT FROM AUTHOR]

The objective of the present work was to develop a sensitive, selective, accurate and precise stability-indicating HPLC method for quantification of degradation products and process-related impurities in fesoterodine fumarate extended-release tablets. The degradation profile was studied by conducting forced degradation studies and all the degradation products formed during degradation were separated. A chromatographic separation was achieved by using Waters Symmetry C18, 250 × 4.6 mm, 5 μm column, maintained at 30°C. Mobile phase A (0.05% trifluoroacetic acid in water) and mobile phase B (90% of 0.02% TFA in methanol and 10% of water) were used in gradient elution mode. A total of 75 μL of each solution was injected and peak responses were quantified at 220 nm. The method was found specific, precise, accurate, linear, rugged, robust and sensitive. During stability studies of fesoterodine fumarate extended-release tablets, one unknown impurity at relative retention time 1.37 was found increasing beyond the identification threshold. This impurity was isolated by using Preparative HPLC and structure was elucidated using mass and NMR spectroscopy. This method is a simple, inexpensive HPLC method that can be used as a routine quality control test for the estimation of impurities in fesoterodine fumarate extended-release tablets. [ABSTRACT FROM AUTHOR]

In our present study, the standard chemicals of triacetin were purified by reverse-phase and normal-phase semi-preparative high-performance liquid chromatography (HPLC), and 1H NMR and 13C NMR were employed to determine the purity and structure of triacetin. Moreover, a simple and rapid HPLC-photodiode array (PDA) method was developed to determine the contents of triacetin in 30 batches from different suppliers. The chromatographic separation was performed on a Phenomenex Gemini-NX C18 column (250 × 4.6 mm, 5 μm) using a gradient elution system of water and acetonitrile (contained 0.1% of formic acid) solution with a flow rate of 1.0 mL/min at 30°C at 210 nm. Sample preparation method is rapid and energy efficient, and the obtained sample have a good purity. Validation shows good specificity, linearity (R 2 = 0.9995), precision, stability, repeatability (% RSD < 2.80) and the average recovery (99.72%) of triacetin. The content of triacetin in most samples is concentrated in 94–97%. This developed approach is simple, rapid, accurate and can be used to quickly determine the purity and the content of triacetin in plasticizers and filter plugs. [ABSTRACT FROM AUTHOR]

Chimonanthi Radix (CR) is widely used in the treatment of influenza in China. Extensive studies revealed that the major bioactive constituents of CR were coumarins. However, pharmacokinetic study of coumarins in CR has not been fully studied. The purpose of this study was to establish a convenient and effective high-performance liquid chromatography–tandem mass spectrometry method that was used to simultaneously determine scopoletin, scopolin and isofraxidin in rat plasma after oral administration of CR extract using xanthotoxin as the internal standard. The chromatographic separation was carried out on a COSMOCORE C18 column (100 × 2 mm, 2.6 μm), using gradient elution with the mobile phase consisting of 0.1% formic acid (A) and acetonitrile (B). Three coumarins and IS were quantified by positive ion electrospray ionization in multiple reaction monitoring mode. The method was fully validated in terms of specificity, accuracy, precision (intra- and inter-day), matrix effect, recovery as well as the stability of the analytes under various conditions. The results could provide further research foundation for anti-influenza mechanism of three coumarins in CR. [ABSTRACT FROM AUTHOR]

Dipeptidyl peptidase-4 inhibitors, so-called gliptins, constitute a fairly novel class of oral hypoglycemic agents. The development and validation of an automated online SPE-LC-UV method to determine intact sitagliptin, saxagliptin, vildagliptin and metformin simultaneously in human urine samples were performed. For the two-dimensional chromatographic separation, a Gemini C18 (250.0 × 4.6 mm i.d. 110 A0, 5.0 μ) analytical column and a gradient elution with 10.0 mM o- phosphoric acid and methanol and for the online SPE analysis of urine samples, a LiChrospher® ADS SPE-column (20.0 mm × 2.0 mm i.d. 25.0 μm) were used through the study. The fractionation, transfer, elution and separation of the spiked urine samples were achieved in just 9.57 min runtime with 12.0 mL of solvent consumption which was green and economical compared to other sample preparation methods. The calibration curves were determined to be linear in a wide range of 0.10–100.00 μg/mL with satisfactory regression coefficients. Method developed for two-dimensional determination of gliptins would be useful as a reference in therapeutic drug monitoring and screening for forensic medical cases which involve the abuse, unintentional or misuse of multiple gliptins in terms of its practical use, easy detection and reliable results. [ABSTRACT FROM AUTHOR]

Sacubitril (SBT) is a neprilysin inhibitor, approved by food and drug administration (FDA) in 2015, under the FDA's priority review process. In this work, we report the validated stability indicating method of SBT by employing quality by design (QbD) principles related to analytical method development, capable in separation of 11 impurities. Chromatographic separation was performed on an ascentis phenyl hexyl column using 10 mM KH2PO4 as a mobile phase-A and the pH adjusted to 2.1. Methanol: acetonitrile (70:30 v/v) solvent mixture was employed as the mobile phase-B in a gradient mode of elution at a flow rate 0.8 mL/min at 30°C. The column effluents were monitored by a photo diode array detector set at a wavelength of maximum absorption 254 nm noted for all the impurities and furthermore for SBT. This method was remarked to be accurate in the range from 92 to 116%, precise with relative standard deviation 0.9% for SBT (0.8 mg/mL) and 1.0 to 2.1% for its related impurities (0.0005 mg/mL) also linear with correlation coefficient r  ≥ 0.9989. The limits of quantification for all impurities were 0.05% with respect to sample concentration 0.8 mg/mL. The developed method revealed a good method operable design range for the experimental chromatographic conditions. Forced degradation of SBT carried under acidic, basic and oxidative stressed conditions manifested that the method is stability indicating. [ABSTRACT FROM AUTHOR]

In the present study, an online liquid extraction coupled with high-performance liquid chromatography-2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (HPLC-ABTS) system for rapid screening of antioxidants in tea samples was proposed. As an example, the tea samples were firstly extracted by online HPLC extractor with mobile phase at 70°C, then the hyphenated HPLC-ABTS was used for the chromatographic separation on a Poroshell EC C18 column by 0.3% aqueous formic acid and acetonitrile with a gradient elution at 1.5 mL·min−1, and the UV and antioxidant chromatograms with detection wavelengths at 270 nm and 750 nm were recorded, respectively. The established system integrated the processes of online HPLC sample extraction, HPLC separation and online antioxidants detection, the total analysis time of which was <20 min. The developed method was successfully applied to samples of green tea, oolong tea and black tea. As a result, 11 antioxidants were found in tea samples, including gallocatechin, epigallocatechin, catechin, chlorogenic acid, epicatechin, epigallocatechingallate, epicatechingallate, rutin, 1,4,6-trigalloylglucose, quercetin-3-glycoside and kaempferol-3-glucoside. The combined online liquid microextraction and online HPLC-ABTS method is a rapid and green approach for the quality evaluation of tea. [ABSTRACT FROM AUTHOR]

Microemulsion eluents have been found to have excellent potential uses in high-performance liquid chromatography (HPLC). Here, a novel, environmentally benign and simple method using concentration/flow-rate double-gradient elution using a microemulsion eluent was used to separate water- and fat-soluble vitamins simultaneously and rapidly. Preliminary screening experiments were performed to determine the optimum column type, surfactant concentration, co-surfactant to surfactant ratio, oil, mobile phase pH and microemulsion concentration. The resolution and analysis time were simultaneously optimized using concentration/flow-rate double-gradient elution. The optimized method simultaneously separated water- and fat-soluble vitamins using a Venusil ASB C8 column and a combination of isocratic and linear gradient elution modes using a microemulsion mobile phase (solvent A) consisting of 3.5% (w/w) sodium dodecyl sulfate, 10.5% (w/w) n -butanol, 0.8% (w/w) n -octanol and 85.2% (w/w) water and water (solvent B) at pH 2.50. The optimum detection wavelength was 283 nm. The method was validated and used to analyze a solid pharmaceutical sample. [ABSTRACT FROM AUTHOR]

A HPLC-DAD method was established for the simultaneous determination of eight components in Leonuri Herba from different habitats, as well as providing methodological reference for quality control of Leonuri Herba. In this study, absolute ethanol extracts of the medicinal material were considered as the sample solutions to be analyzed. Agilent ZORBAX SB-C18 column (250 mm × 4.6 mm, 5 μm) was used for determination maintained at the temperature of 30°C. Gradient elution was performed with a mobile phase of methanol (B)-0.1% phosphoric acid solution (A) at the flow rate of 1.0 mL·min−1. The analysis was carried out at the wavelength of 225, 280 and 320 nm. The measured eight components showed good linear relationships within their own concentration range. Average recoveries ranged from 98.83 to 100.36% with RSDs of 1.14~1.97%. The proposed method was found to be simple, accurate and reproducible, which provided an effective quantitative analytical method for quality control of Leonuri Herba from different habitats. [ABSTRACT FROM AUTHOR]

Two high-performance liquid chromatography-diode array detection methods have been developed and validated for the simultaneous quantification of genistein (GNS) and all trans retinoic acid (ATRA) as a novel anticancer combination therapy in their co-formulated nanoparticles and in rat plasma. Separation was performed on C18 column (250 × 4.6 mm, 5 μm) using celecoxib as internal standard. A mobile phase containing acetonitrile and water adjusted to pH 3 using 1% trifluoroacetic acid was delivered in gradient elution modes with time programmed UV detection. For extraction of the drugs and the internal standard from rat plasma, liquid- liquid extraction was applied. The proposed methods were validated as per International Conference on Harmonisation (ICH) guidelines (in the range 0.1–10 μg/mL for analysis of GNS and ATRA in nanoparticles) or according to Food and Drug Administration (FDA) guidance on bioanalytical method validation (in the range 0.025–20 μg/mL for analysis of GNS and ATRA in rat plasma). Pharmacokinetic study in six rats was performed following intravenous (IV) administration of a single dose of 0.5 mg/Kg of GNS and ATRA. The drugs' concentrations were measured up to 24 hours, and different pharmacokinetic parameters were calculated. The obtained parameters were comparable with the reported values for IV administration of each drug alone in rats. This confirms the applicability of the proposed method in monitoring the levels of the two drugs in vivo following their coadministration and indicating that the two drugs could be coadministered as a promising novel combination therapy for the treatment of lung cancer without great alteration in their pharmacokinetic parameters compared with their individual IV administration. [ABSTRACT FROM AUTHOR]

An effective and sensitive liquid chromatographic–electrospray ionization tandem mass-spectrometric (LC–ESI-MS/MS) method was developed and validated for quantification of escitalopram oxalate (ESC-OX), antidepressant drug in spiked human urine and pharmaceutical formulations. In this work, simple liquid–liquid extraction was optimized and used for extraction of cited drug from urine samples. The chromatographic separation was attained within 6 min including re-equilibration time by using gradient elution with 0.1% formic acid in acetonitrile and 0.1% formic acid in water as mobile phase, Zorbax Eclipse RP C18 (50 × 2.1 mm) column was used with a particle size of 1.8 μm; the flow-rate was 0.35 mL min−1. Ion signal m/z 262.0 and 109.0 for ESC-OX product ions were monitored at positive ESI mode. Validation of the method was carried out according to the ICH Q2 (R1) guidelines and EMEA criteria. The method was linear over 79−196,450 pg mL−1 with a regression of 0.9999 and 0.9993 for both standard and urine samples. The LOD was 3.88 and 10.66 pg mL−1 for standard and urine samples, respectively, while lower limit of quantification was 79 pg mL−1. [ABSTRACT FROM AUTHOR]

A simple and enantioselective method was developed and validated for the simultaneous determination of (R)- and (S)-trelagliptin in beagle dog plasma by chiral liquid chromatography tandem mass spectrometry. Trelagliptin enantiomers and (R)-rabeprazole (as internal standard, IS) were extracted from plasma samples by liquid–liquid extraction and separated on a CHIRALCEL OX-3R column using acetonitrile-5 ammonium bicarbonate as the mobile phase in gradient elution mode. The multiple reactions monitoring transitions of m/z 358.1→341.2 and 359.9→150.1 were used to quantify trelagliptin enantiomers and IS, respectively. This method was validated for sensitivity, specificity, linearity, precision, accuracy and stability of specific analytes under various conditions. And it was successfully applied to evaluating the pharmacokinetic profile of trelagliptin enantiomers in beagle dogs after single intravenous administration of (R)-trelagliptin injection (at 1 mg/kg) and oral administration (at 6.7 mg/kg). In this study, no chiral bioconversion of (R)-trelagliptin to (S)-trelagliptin in beagle dog plasma was observed. The absolute bioavailability of (R)-trelagliptin was identified to be 128.2%. [ABSTRACT FROM AUTHOR]

Andrographis paniculata is an important traditional Chinese herbal material widely used for treatment of fever and diarrhea. The three diterpenoids [andrographolide (AP), dehydroandrographolide (DP) and neoandrographolide (NP)] in A. paniculata were characterized as the key active components for its extractive and related medicinal preparations. A rapid and accurate quantitative analysis of these three diterpenoids in A. paniculata capsules was accomplished by means of a valid and reliable high-performance liquid chromatography with tandem mass spectrometric (HPLC–MS/MS) analytical method. An optimized gradient elution method, which under the mobile phase consisting of methanol and water, was established successfully. An XDB C18 column (3.5 μm, 2.1 mm × 50 mm) was successfully applied to separate these three diterpenoids at the flow rate of 0.55 mL/min. A triple quadrupole mass spectrometer with multiple reaction monitoring (MRM) mode using an electrospray ionization source was served for analytical detection. The linearity, specificity, accuracy, recovery, precision, stability and repeatability were demonstrated to fully confirm the validity of this study. Good linear regression relationships for the three analytes were obtained over the range of 0.50–1000 ng/mL. Intra-day and inter-day precisions were evaluated with relative standard deviation < 7.62%, and the extraction recovery varied from 93.8% to 102.0%. The rapid and accurate HPLC–MS/MS analytical method was developed for the quality evaluation of A. paniculata capsules successfully. The content of AP, DP and NP obtained were 3.90–4.08, 4.77–5.04, 4.32–4.48 mg/g in A. paniculata capsules, respectively. Moreover, it is expected that this analytical technique can be applied to detect three effective components rapidly and accurately in other different medicinal preparations of A. paniculata as a method for their quality control. [ABSTRACT FROM AUTHOR]

In the present study, a systematic validated method was developed for the determination of two key dietary dihydrochalcones (DHC) viz. phloridzin (PZ) and phloretin (PT) in the leaves of Sikkim crabapple (Malus sikkimensis) using HPLC-Photo Diode Array (PDA). Chromatographic separation was optimized on a C18 column using a gradient elution of water/acetonitrile with the flow rate of 1.0 mL/min at 25°C at 280 nm. Sample preparation approach is rapid and energy efficient, and it requires no pre-concentration before analysis. Validation showed a good analytical performance in terms of specificity, linearity (r2 > 0.999), precision (% RSD < 1.08), recovery (97–100.4%) and sensitivities (limits of detection: 12.48 and 14.95 ng/mL; limit of quantification: 41.61 and 49.85 ng/mL) of PZ and PT , respectively. Developed approach was employed for targeted phytochemical analysis in the bark and fruits of M. sikkimensis. The PZ content in the bark and leaves was highest (12–13 mg/100 mg), about 90-fold higher than fruits. PT was only present in the leaves (0.57 mg/100 mg). The comparative data on PZ and PT content in various wild apple species/cultivar from different countries have also been discussed. The reliability of the validated method was established by analyzing global and expanded uncertainties in two DHC determinations in wild apple. The present method fulfills the technical requirement of ISO 17025:2017 for quality control of M. sikkimensis. [ABSTRACT FROM AUTHOR]