The green profile of the developed method is assessed and compared with previously reported methods. Percutaneous coronary intervention is a procedure where a catheter is utilized to place a stent in order to facilitate opening of the blood vessels in the heart. Triple antithrombotic therapy includes oral anticoagulation as warfarin and dual antiplatelet therapy (composed of aspirin and clopidogrel bisulfate). The aim of the current study was to evaluate the pharmacokinetic parameters of ASP, WAR and CLP and to investigate the possible interaction between the three drugs upon co-administration in rats. A selective and precise RP-HPLC method was developed for the simultaneous determination of ASP, WAR and CLP in rat plasma. Pharmacokinetic study was conducted in rats that received ASP, WAR and CLP as an application of the developed method. From the statistical evaluation of the pharmacokinetic parameters, it was observed that the co-administration of ASP, WAR and CLP significantly increased the ASP and CLP bioavailability in rats. A significant drug-drug interaction was confirmed in the current study. The elevated Cmax of ASP and CLP upon the co-administration of ASP, WAR and CLP may explain the reported bleeding.

Central composite design based RP-HPLC method optimization for the synchronized analysis of Efonidipine Hydrochloride Ethanolate (EFE) and Chlorthalidone (CHL) in tablet. The effective separation was performed using Inertsil ODS C18 column (250 × 4.6mm, 5μm), PDA detector with 0.05M KH2PO4 Buffer (pH4.5): Acetonitrile (40:60%v/v) mobile phase. Independent variables were investigated include the concentration of KH2PO4 (X1) and flow rate of mobile phase (X2). Based on responses obtained (retention time, resolution and tailing factor), the optimum condition selected was X1 = 40% and X2 = 1ml/min. Optimized HPLC condition was validated by assessing validation parameters and it meets the acceptance criteria set by ICH. The linear calibration curve was found to be in the quantity range 6.25-18.75 and 20-60μg/ml Assay of drugs was 100.94 and 100.06% for CHL and EFE. The validated RP-HPLC-PDA method can be used for routine analysis of EFE and CHL in tablet.

This study presents the development and validation of a gas chromatography (GC) method using cryo-enrichment for the analysis of α-pinene and β-caryophyllene in Cannabis sativa plant. Cryo-enrichment is a method that involves cooling part of the GC column to improve some aspect of chromatographic analysis. The aim of this study was to improve upon previous GC cryo-enrichment prototype and to create and validate a method for the analysis of these terpene compounds, which have received increasing attention for their medicinal properties. The improved cryo-enrichment device used in this study was built in-house and used a custom-built aluminum GC column holder cooled by a two-stage cryo-cooler. The validated method was found to be precise, accurate and sensitive, with good repeatability.

A two-component model of gradient elution chromatography is investigated to theoretically study the effects of simultaneous variations in temperature and solvent strength on the retention behaviors of elution profiles in thermally insulated liquid chromatographic columns. The gradient elution technique is based on the gradual increase or decrease in eluent strength during the chromatographic operation by varying the composition of the mobile phase. The enthalpy of adsorption is primarily responsible for internal temperature variations inside the column, as heat adsorbs during the adsorption process and releases in the desorption phase. Both types of variations change the propagation speeds of moving pulses inside the column which can lead to better separation of the components and a reduction in the recycling time for the next injection. The equilibrium dispersive model (EDM) coupled with the energy balance equation for temperature and transport equation for the volume fraction of the solvent is utilized to simulate this complex process. The resulting nonlinear model equations are approximated by applying a semi-discrete second-order finite volume scheme. The numerical solutions are used to study the impact of a gradient starting and ending times, volume-fraction of the solvent, solvent strength parameter, the slope of gradient, enthalpy of adsorption, injection temperature, and the ratio of specific heats on the concentration profiles.

A simultaneous ultra-performance liquid chromatography photodiode array detection method was developed and validated for Elvitegravir, Tenofovir and Emtricitabine and Cobicistat drugs in tablet dosage forms. Effective liquid chromatographic quantification was achieved using a Luna C18 (100 × 2.6mm, 1.6μ) column with an acetonitrile: 0.1% v/v trifluoro acetic acid (80:20% v/v) mobile phase and a photo diode array detector at 260nm for a shorter run time of 3min. The respective retention times for Elvitegravir, Tenofovir, Emtricitabine and Cobicistat were 0.311, 0.792, 1.379 and 2.045min. The range of linearity was 37.50-225.00, 2.50-15.00, 50.00-300.00and 37.50-225.00μg/mL for Elvitegravir, Tenofovir, Emtricitabine and Cobicistat, respectively. A mass spectrometer was employed for quantitative analysis using electron spray ionization multiple reaction monitoring in positive mode. The developed method was validated for different parameters to meet the acceptance criteria as per ICH Q2 (R1) guidelines. Using UPLC-ESI-MS, 12 degradants were identified and their mechanisms were studied.

Yanyangke mixture (YM) is composed of 12 kinds of traditional Chinese medicine (TCM) used for the treatment of patients with cough, dry throat and other diseases caused by acute or chronic pharyngitis or patients with difficulty in expectoration. With the wide application of YM in clinical practice, its quality control has attracted huge attention. Based on the multi-component characteristics of Chinese herbal medicines, it is pertinent to establish a quality evaluation system. A new idea is to adopt gas chromatography-mass spectrometry (GC-MS) chemical composition identification, GC-MS fingerprint, and GC content determination as a potential quality control index of the volatile oil in YM. In this study, the volatile oil of YM was extracted by steam distillation, and the chemical components of the volatile oil were analyzed by GC-MS, and 43 chemical components were identified. The fingerprint of the volatile oil from YM was established and the similarity evaluation was performed. Combined with chemometric methods, such as cluster analysis, principal component analysis and partial least squares analysis, the chemical composition differences of the volatile oil from different batches of YM were compared and the symbolic components affecting the quality of the volatile oil from different batches of YM were excavated. Finally, three components were selected as the potential active component markers of YM and the GC content determination method of these three components was established. A rapid, reasonable, and effective quality evaluation and control method of YM volatile oil was established, which provided a reference for further development and research on YM, as well as a new idea for research on other TCM prescriptions.

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 0.45mL/min, linear gradient elution in both labs. The AG and PTX were detected on the PDA detector at 224 and 227nm wavelength with retention time of 4.5 ± 0.34 and 8.2 ± 0.02min and limit of detection was found 0.028 ± 0.004μg/mL, and 0.028 ± 0.0007μg/mL, whereas limit of quantification as 0.086 ± 0.011μg/mL and 0.088 ± 0.0014μg/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.

The dry powder inhalation formulation containing vilanterol trifenatate, umeclidinium bromide and fluticasone furoate intended for the therapy of bronchospasm related to chronic obstructive pulmonary disease and bronchial asthma was selected for the development and validation of a novel, selective, accurate, precise, quick and cost-efficient reversed-phase, high-performance liquid chromatography method. Neither an official monograph nor a single method has yet been published for the simultaneous estimation of these three compounds, which makes this method novel. The stationary phase of an ACE-C18-PFP column (250mm × 4.6mm, 5μ) was used with a mobile phase of 25-mM sodium perchlorate buffer (pH2.5 adjusted with ortho-phosphoric acid) and acetonitrile (40:60% v/v) at a flow rate of 1mL/min to optimize chromatographic variables. The column temperature was kept at 40°C, and detection was at 224nm, which was the isosbestic point of these three drugs. Well-resolved good peak symmetry was obtained for all three molecules by isocratic elution in less than 10min, and the retention times of vilanterol trifenatate, umeclidinium bromide and fluticasone furoate were found to be 3.7, 5.4 and 8.3min, respectively. The proposed method was validated as per ICH Q2 (R1) guidelines, and the calibration curves were linear in concentration ranges of 5-35μg/mL for vilanterol trifenatate, 5-80μg/mL for umeclidinium bromide and 5-150μg/mL for fluticasone furoate, with mean % recoveries of 99-100%. The limits of detection and quantitation are 0.15 and 0.45μg/mL for vilanterol trifenatate, 0.58 and 1.77μg/mL for umeclidinium bromide and 0.32 and 0.96μg/mL for fluticasone furoate, respectively. Hence, the proposed RP-HPLC technique was successfully used to quantify the inhalation formulation containing all three compounds.

Pinus massoniana needles, a traditional herb, were applied to prevent hair loss in China. Studies available mainly focused on pine needle flavonoids with various biological activities. However, there has been no pharmacokinetics study of the flavonoids from Pinus needles extract. A selective and sensitive ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed to simultaneously quantify taxifolin, quercetin and catechin in rat plasma. To separate the three constituents, an Agilent Extend-C18 column (2.1mm × 100mm, 1.8μm) was used with a mobile phrase of (A) 0.1% formic acid and (B) acetonitrile. The analytes were measured by multiple reaction monitoring in the negative ionization mode. There was good linearity in the established UHPLC-MS/MS method, with a coefficient of determination (r2) of >0.99. The accuracy, intra-day and inter-day precision and recovery were all satisfactory and these 3 compounds were stable under the tested conditions. The validated method in this study was successfully applied to pharmacokinetic study in healthy rats after oral and transdermal administration of Pinus needles extract. The results could provide further research foundation for pine needle extract as external preparations.