Simultaneous determination of metoprolol succinate and amlodipine besylate in human plasma by liquid chromatography-tandem mass spectrometry method and its application in bioequivalence study.

A simple, sensitive and specific liquid chromatography-tandem mass spectrometry method was developed and validated for quantification of metoprolol succinate (MPS) and amlodipine besylate (AM) using hydrochlorothiazide (HCTZ) as IS in human plasma. Both the drugs were extracted by simple liquid-liquid extraction with chloroform. The chromatographic separation was performed on a reversed-phase peerless basic C18 column with a mobile phase of methanol-water containing 0.5% formic acid (8:2, v/v). The protonated analyte was quantitated in positive ionization by multiple reaction monitoring with a mass spectrometer. The method was validated over the concentration range of 1-100 ng/ml for MPS and 1-15 ng/ml AM in human plasma. The MRM transition of m/z 268.10-103.10, m/z 409.10-334.20 and m/z 296.00-205.10 were used to measure MPS, AM and HCTZ (IS), respectively. This method was successfully applied to the pharmacokinetic study of fixed dose combination (FDC) of MPS and AM formulation product after an oral administration to Indian healthy human volunteers.

Determination of ranolazine in human plasma by LC-MS/MS and its application in bioequivalence study.

A simple, sensitive and specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for quantification of ranolazine in human plasma. The analytical method consists in the precipitation of plasma sample with methanol, followed by the determination of ranolazine by an LC-MS/MS. The analyte was separated on a Peerless Cyano column (33 mm x 4.6 mm, 3 microm) an isocratic mobile phase of methanol-water containing formic acid (1.0%, v/v) (65:35, v/v) at a flow rate of 1.0 ml/min. Protonated ions formed by a turbo ionspray in positive mode were used to detect analyte and internal standard (IS). The MS/MS detection was made by monitoring the fragmentation of m/z 428.20-->279.50 for ranolazine and m/z 448.30-->285.20 for internal standard on a triple quadrupole mass spectrometer. The method was validated over the concentration range of 5-2000 ng/ml for ranolazine in human plasma with correlation coefficient of 0.9937 (S.D.: +/-0.00367, range: 0.9895-0.9963). The accuracy and precision values obtained from six different sets of quality control samples analyzed in separate occasions ranged from 94.53 to 117.86 and 0.14% to 4.56%, respectively. Mean extraction recovery was 82.36-94.25% for three quality control (QC) samples and 88.37% for IS. Plasma samples were stable for three freeze-thaw cycles, or 24h ambient storage, or 1 and 3 months storage at -20 degrees C. Processed samples (ready for injection) were stable up to 72 h at autosampler (4 degrees C). The developed method was successfully applied for analyzing ranolazine in plasma samples for a bioequivalence study with 12 healthy volunteers.

A rapid LC-ESI-MS/MS method for the quantitation of choline, an active metabolite of citicoline: Application to in vivo pharmacokinetic and bioequivalence study in Indian healthy male volunteers.

A rapid, simple, and sensitive high performance liquid chromatography-tandem mass spectrometry method (LC-ESI-MS/MS) was developed and validated for the determination and pharmacokinetic investigation of choline (CL), active metabolite of citicoline in human plasma using metformin (MF) as IS. The chromatographic separation was performed on a reversed-phase Phenomenx Gemini C18 column with a mobile phase of methanol:water (containing 10mM ammonium formate) (9:1, v/v). The calibration curves were linear over the range of 0.05-5µg/ml. The validated LC-ESI-MS/MS method was successfully applied for the evaluation of pharmacokinetic parameters and bioequivalence study of test and reference control release (CR) tablet preparation of citicoline 1000mg after a single oral administration to all 12 healthy male volunteers.

Pharmacokinetics and bioequivalence study of a fixed dose combination of rabeprazole and itopride in healthy Indian volunteers.

The aim of the present study was to compare the pharmacokinetics of rabeprazole (CAS 117976-89-3) and itopride (CAS 122898-67-3) after oral administration of a rabeprazole (20 mg)-itopride (150 mg) fixed dose combination (FDC) in healthy human volunteers. The bioequivalence of two formulations (test and reference) was determined in 12 healthy Indian male volunteers (age: 25.25 +/- 4.69 years; weight: 60.50 +/- 5.04 kg) in a randomized, single-dose, two-period, two-treatment crossover study. Both formulations were administered orally as a single dose, with the treatments separated by a washout period of 1 week. Rabeprazole and itopride plasma levels were determined by a validated HPLC method using UV detection. The formulations were compared using the pharmacokinetic parameters area under the plasma concentration-time curve (AUC(0-t)), area under the plasma concentration-time curve from zero to infinity (AUC(0-infinity)) and peak plasma concentration (Cmax). General linear model (GLM) procedures were used in which sources of variation were subject, treatment and period. The results indicated that there were no statistically significant differences (P > 0.05) between the logarithmically transformed AUC(0-infinity) and Cmax values between test and reference formulation. The 90% confidence interval for the ratio of the logarithmically transformed AUC(0-t), AUC(0-infinity) and Cmax were within the bioequivalence limits of 0.8-1.25 and the relative bioavailability of rabeprazole and itopride test and reference formulations was 98.24 and 93.65%, respectively.

Bioequivalence study of a sustained release fixed dose combination capsule containing esomeprazole and domperidone in healthy subjects.

OBJECTIVE: The study was designed to determine the relative bioavailability of two sustained release fixed dose combination (FDC) products of two manufacturers containing esomeprazole (CAS 326602-80-6) 40 mg and domperidone (CAS 57808-66-9) 30 mg in 24 healthy male volunteers. The pharmacokinetics of esomeprazole and domperidone individually after oral administration of tablet formulation has been extensively evaluated in adult volunteers. However, no published data are available regarding the combined pharmacokinetics and bioavailability of this particular FDC. METHOD: The study was designed as a randomized, balanced, open-label, 2-period cross-over study. Each subject was randomized at the beginning of the study to receive either a single dose of the Test FDC or Reference FDC during Period I. Following a 7-day wash-out period, all subjects received the alternate formulation during Period II. RESULTS: No statistically significant differences were obtained between the two products with respect to the mean concentration-time profiles or in the pharmacokinetic parameters, including area under the serum concentration-time curve from the present study. The relative extent of absorption as assessed by the AUC ratio (Test/Reference) and C(max), the average value was found to be 1.00 +/- .09 with 90% confidence limits (C.L.) of 0.82-1.18. CONCLUSION: These findings clearly indicate that the two products are bioequivalent in terms of rate and extent of drug absorption. Both preparations were well tolerated with no adverse reactions throughout the study.

Bioequivalence study of a fixed dose combination of nitazoxanide and ofloxacin in Indian healthy volunteers.

OBJECTIVE: The pharmacokinetics of nitazoxanide (CAS 55981-09-4) and ofloxacin (CAS 82419-36-1) has been extensively evaluated in adult human volunteers individually after oral administration of tablet formulation. However, no published data is available regarding the combined pharmacokinetics and bioavailability of this particular fixed dose combination. In light of the above, a clinical study was designed to evaluate the bioequivalence of two fixed dose combination (FDC) products of two manufacturers containing nitazoxanide 500 mg and ofloxacin 200 mg in healthy Indian male volunteers. METHODS: 24 healthy male volunteers (age 25 +/- 4.6 years; weight 74.5 +/- 7.87 kg) were enrolled in this study. Each subject received a Test fixed dose combination and a Reference fixed dose combination formulation in a randomized, single dose, fasting state, two period, crossover study design with a 1-week washout period between the doses. Extraction of the drugs from the plasma was carried out by precipitation method. Analysis of tizoxanide (active metabolite of nitazoxanide) and ofloxacin from plasma samples was done by a simple and sensitive HPLC method using UV detection developed in our laboratory. An analysis of variance was performed on the pharmacokinetic parameters Cmax, AUC(0-t), AUC(0-infinity). using general linear model (GLM) procedures in which sources of variation were subject, formulation, period. RESULTS: The results of this investigation indicated that there were no statistically significant differences between the two products in either the mean concentration-time profiles or in the obtained pharmacokinetic parameters. 90 % confidence limits for the log-transformed data of Cmax, AUC(0-t), AUC(0-infinity) were within the acceptable range of 0.80-1.25. CONCLUSION: Thus, these findings clearly indicate that the two products are bioequivalent in terms of rate and extent of drug absorption. Both the preparations were well tolerated with no adverse reactions seen throughout the study.