ESTIMATION OF CELECOXIB IN HUMAN PLASMA BY RAPID AND SELECTIVE LC-MS/MS METHOD FOR A BIOEQUIVALENCE STUDY

Objective: A selective, sensitive and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay has been developed for the determination of celecoxib (CXB) in negative ionization mode.Methods: Celecoxib and celecoxib-D7 (CXB-D7) as internal standard (IS) were extracted from 300 µl human plasma by solid-phase extraction using strata-X SPE cartridges. Chromatographic separation was achieved on ACE C8-300 (50 × 4.0 mm, 3.0 μm) column using methanol-1.0 mmol ammonium acetate solution in 80:20 (v/v) ratio. The protonated precursor to product ion transitions studied for CXB and CXB-D7 were m/z 380.0 → 315.9 and 387.0 → 323.0, respectively.Results: The limit of detection (LOD) and lower limit of quantitation of the method were 2.50 and 10.0 ng/ml respectively with a linear dynamic range of 10.0-4000 ng/ml for CXB. The intra-batch and inter-batch precision (% CV) and mean relative recovery across quality control levels is<7.2 % and 85.5 % respectively. Matrix effect in human plasma, expressed as IS-normalized matrix factor ranged from 0.99-1.03.Conclusion: The method was successfully applied in healthy subjects using a single dose of 400 mg celecoxib capsules under fasting and fed conditions. The reproducibility in the measurement of study data is demonstrated by incurred sample reanalysis

COMPARATIVE EVALUATION OF FIRST ORDER, ABSORBANCE RATIO AND BIVARIATE SPECTROPHOTOMETRIC METHODS FOR DETERMINATION OF ATOVAQUONE AND PROGUANIL IN PHARMACEUTICAL FORMULATION MALARONE®

Objective: Three simple, rapid, accurate and precise spectrophotometric methods have been developed for the simultaneous estimation of atovaquone and proguanil hydrochloride in pharmaceutical preparations.Methods: The determination of drugs was carried out using the first order derivative, absorbance-ratio and bivariate spectrophotometric methods. The methods were validated for their linearity, accuracy and precision, recovery and ruggedness according to the ICH guidelines.Results: The linearity was established in the concentration range of 1.0-10 µg/ml for atovaquone and 0.5-8.0 µg/ml for proguanil hydrochloride by all three methods. The limit of detection (LOD) and the limit of quantitation (LOQ) of the methods varied from 0.252 to 0.270 µg/ml and 0.764 to 0.825 µg/ml for atovaquone and 0.119 to 0.156 µg/ml and 0.361 to 472 µg/ml for proguanil hydrochloride respectively. The intra-and inter-batch accuracy (% recovery) and precision (% RSD) ranged from 99.16 to 101.05 % and 0.603 to 1.048 for atovaquone and 99.74 to 101.12 % and 0.593 to 1.001 for proguanil respectively.Conclusion: The proposed methods were applied to a pharmaceutical formulation with acceptable accuracy and precision without any interference from commonly used excipients and additives. The results show that all three methods are comparable, cost effective and rapid and thus can be readily used in quality control labs for routine analysis of these drugs.Â

SENSITIVE AND RAPID ESTIMATION OF LAPATINIB, AN ANTICANCER DRUG IN SPIKED HUMAN PLASMA BY LC-MS/MS

Objective: The work presents a sensitive, selective and rapid determination of lapatinib, a potent anticancer drug in human plasma by liquid chromatography-tandem mass spectrometry.Methods: Liquid-liquid extraction of lapatinib and lapatinib-d4, added as an internal standard (IS) was carried out from 100 µl plasma sample. Chromatographic analysis was performed on ACE C18 (100 mm × 4.6 mm, 5 µm) column using 10 mmol ammonium formate buffer (pH 3.5) and acetonitrile (10:90, v/v) as the mobile phase. The precursor ion → product ion transitions for lapatinib (m/z 581.1 → 365.2) and IS (m/z 585.1 → 365.0) were monitored on a triple quadrupole mass spectrometer in the positive electrospray ionization mode. The method was validated in accordance with the US FDA guidelines.Results: A linear concentration range was established from 2.50-2500 ng/ml for lapatinib. The intra-batch and inter-batch precision were ≤ 4.81 %. The recovery of lapatinib and IS from plasma samples ranged from 88.7 to 95.8 % and 85.9 to 96.5 % respectively. The accuracy and precision (% CV) for the stability of lapatinib under different storage conditions showed a variation from 95.2 to 102.2 % and 1.19 to 4.35 % respectively at low and high QC levels. Under optimized chromatographic conditions, the retention time for lapatinib was 1.406 min with a total run time of 2.5 min for each sample.Conclusion: The validation results demonstrate that the method is simple, accurate, precise and reproducible. The developed method can be readily used for pharmacokinetics/bioequivalence studies in patients as well as healthy subjects.Â

Simultaneous analysis of aliskiren and hydrochlorothiazide in pharmaceutical preparations and spiked human plasma by HPTLC

AbstractA simple, selective and precise method based on HPTLC has been developed for the simultaneous determination of aliskiren and hydrochlorothiazide in a fixed-dose tablet formulation and human plasma. The chromatography was performed on silica gel 60 GF254 plates, with a mobile phase consisting of methanol–chloroform (6:4, v/v). Densitometric analysis of the analytes was carried out at 225nm. Under optimized conditions, the Rf values were 0.26±0.02 and 0.71±0.02, and the resulting regression plots were linear (r2≥0.9997) in the concentration ranges of 1.00–10.0 and 0.10–1.00μgband−1 for aliskiren and hydrochlorothiazide. The limit of detection and limit of quantitation of the validated method were 0.206 and 0.624μgband−1 for aliskiren and 0.015 and 0.046μgband−1 for hydrochlorothiazide, respectively. The % expected content of aliskiren and hydrochlorothiazide in the commercial tablet formulation was 99.2% and 101.3%, respectively. For spiked plasma sample preparation, the analytes and nebivolol internal standard were extracted from 500μL of plasma sample by solid-phase extraction on LiChrosep® DVB-HL cartridges. The mean extraction recovery of aliskiren and hydrochlorothiazide from human plasma was 87.2% and 76.5%, respectively. In addition, the stability of the analytes in plasma was established under different storage conditions

Quantitation of nitrofurantoin in human plasma by liquid chromatography tandem mass spectrometry

A reliable, selective and sensitive LC-MS/MS assay has been proposed for the determination of nitrofurantoin in human plasma. The analyte and nitrofurazone were extracted from 100 µL of human plasma via SPE on Strata-X 33 µm extraction cartridges. Chromatography was done on a BDS Hypersil C18 (100 mm × 4.6 mm, 5 µm) column under isocratic conditions. Quantitation was done using the multiple reaction monitoring (MRM) mode for deprotonated precursor to product ion transitions of nitrofurantoin (m/z 237.0 → 151.8) and nitrofurazone (m/z 197.0 →123.9). The limit of detection and the lowest limit of quantitation of the method were 0.25 ng mL–1 and 5.00 ng mL–1, respectively, with a linear dynamic range of 5.00–1500 ng mL–1 for nitrofurantoin. The intra-batch and inter-batch precision (RSD, %) was ≤ 5.8 %, while the mean extraction recovery was > 92 %. The method was successfully applied to a bioequivalence study of a 100 mg nitrofurantoin capsule formulation in 36 healthy subjects

Standardization of Variables for Dyeing Cotton Fabric with Five Synthesized Reactive Dyes

This study presents standardization of dyeing variables for dyeing of five synthesized reactive dyes (Red A, Red B, Red C, Orange D and Black BE) on 100 % cotton fabric. These dyes contained sulfo vinylsulfone functionality and were prepared by either reacting cyanuric chloride with H-acid and coupling with the diazotized product of sulfo vinylsulfone/sulfo tobiaz acid or reacting diazotized sulfo vinylsulfone with H-acid/sodium napthonate under optimized conditions. Different variables which affect the process of dyeing like dye concentration, dyeing temperature, pH of dyeing solution, dyeing time and concentration of auxiliaries used during dyeing were systematically evaluated. All measurements were made at wavelength maxima (λmax) of respective dyes Red A (540 nm), Red B (535 nm), Red C (530 nm), Orange D (520 nm) and Black BE (630 nm). The results showed that 3 % dye concentration was adequate for maximum dye absorption on the cotton fabric and 1 % was ideal for fastness to sunlight and wash. The optimized values for other variables were, dyeing temperature: 80 ºC, pH of dyeing: 11.0, drying time: 90 min; and 80/85 g/L of sodium chloride and 20/25 g/L of sodium carbonate as auxiliaries for 1 % and 3 % dye concentration respectively

Simultaneous quantification of prodrug oseltamivir and its metabolite oseltamivir carboxylate in human plasma by LC–MS/MS to support a bioequivalence study

AbstractA simple, precise and rapid liquid chromatography–tandem mass spectrometry (LC–MS/MS) method has been developed and validated for the simultaneous determination of oseltamivir and oseltamivir carboxylate, a neuraminidase inhibitor, using their deuterated analogs as internal standards (ISs). The method involved solid phase extraction of the analytes and ISs from 200μL human plasma with no reconstitution and drying steps. The chromatographic separation was achieved on a Symmetry C18 (100mm×4.6mm, 5μm) column using 10mM ammonium formate and acetonitrile (30:70, v/v) as the mobile phase in a run time of 2.0min. Quantitation of analytes and ISs were done by multiple reaction monitoring on a triple quadrupole mass spectrometer in the positive ionization mode. The linearity of the method was established in the concentration range of 0.5–200ng/mL and 2.0–800ng/mL for oseltamivir and oseltamivir carboxylate respectively. The mean extraction recovery for oseltamivir (94.4%) and oseltamivir carboxylate (92.7%) from spiked plasma samples was consistent and reproducible. The application of this method was demonstrated by a bioequivalence study in 42 healthy Indian subjects with 75mg oseltamivir phosphate capsules. The assay reproducibility was established by reanalysis of 151 incurred subject samples

COMPLEXATION STUDY OF GLIMEPIRIDE WITH Mg2+, Ca2+, Cu2+AND Zn2+CATIONS IN METHANOL BY CONDUCTOMETRY, SPECTROPHOTOMETRY AND LC-MS

Objective: The present work describes complexation study of sulfonylurea based drug, glimepiride with divalent metal ions (Mg2+, Ca2+, Cu2+and Zn2+) in methanol by conductometry, spectrophotometry and liquid chromatography-mass spectrometry. Methods: The stoichiometry of resulting metal ion-glimepiride complexes were ascertained by molar conductance vs. mole ratio of glimepiride/metal ion plots, Job’s method of continuous variation and liquid chromatography-mass spectrometric analysis. The values of enthalpy and entropy of complexation reactions in methanol were obtained from van’t Hoff plots. Results: The formation constants of 1:1 (M2+: glimepiride) complexes at different temperatures followed the order Mg2+>Cu2+>Zn2+>Ca2+by conductometry as well as spectrophotometry. High molar conductivities were observed for all the complexes indicating formation of charged complex and the results were supported by the presence of protonated precursor complex ions in the mass spectral study. Conclusion: The stability of complexes increased with temperature suggesting endothermic nature of complexation reactions. The thermodynamic data showed that all the complexes formed were entropy stabilized and enthalpy destabilized. A good linear relationship between ∆H and T∆S values suggests existence of entropy–enthalpy compensation in the complexation of these four cations with glimepiride

Simultaneous densitometric analysis of amlodipine, hydrochlorothiazide, lisinopril, and valsartan by HPTLC in pharmaceutical formulations and human plasma

<p>A simple, accurate, and precise high-performance thin layer chromatographic (HPTLC) method has been developed and validated for the simultaneous quantification of antihypertensive drugs, amlodipine (AML), hydrochlorothiazide (HCTZ), lisinopril (LIS), and valsartan (VAL) in their pharmaceutical formulations and human plasma. Separation of the drugs was performed on aluminum-backed layer of silica gel 60 F₂₅₄ using a mixture of methanol–dichloromethane–glacial acetic acid (9.0:1.0:0.1, v/v/v) as the mobile phase. Densitometric determination of the separated spots was done at 215 nm. The retention factors (<i>R</i>_f) obtained under the optimized conditions were 0.56, 0.75, 0.29, and 0.67 for AML, HCTZ, LIS, and VAL, respectively. Linearity of the method was established in the range of 200–1,500 ng/band for AML, 300–1,500 ng/band for HCTZ, 400–2,000 ng/band for LIS, and 1,000–7,000 ng/band for VAL. The limit of detection/limit of quantitation of the method found were 54.21/164.28, 77.27/234.15, 83.45/252.87, and 156.48/474.19 ng/band for AML, HCTZ, LIS, and VAL, respectively. To determine the drugs in spiked plasma samples, solid phase extraction was performed, which provided highly consistent and quantitative recovery for all four drugs. The method was satisfactorily applied for the analysis of different tablet formulations and proved to be specific and accurate for the quality control of these drugs.</p