Bioequivalence studies of two different film-coated tablet formulations of valacyclovir of two different strengths in healthy volunteers.

These studies were conducted in order to assess the bioequivalence of two film-coated formulations containing 250 mg and 1000 mg of valacyclovir (INN: valaciclovir; CAS 124832-26-4), which is the L-valyl ester and a pro-drug of the antiviral drug acyclovir (INN: aciclovir). In the study with valacyclovir 250 mg, 36 healthy subjects were enrolled in a randomized, single-dose, open-label, 2-way crossover study, with a washout period of 10 days. In the study with valacyclovir 1000 mg, 46 healthy subjects were enrolled in a randomized, single-dose, open-label, 2-way crossover study, with a washout period of 7 days. Plasma samples were collected up to 36 h postdose for both studies. Valacyclovir levels were determined by liquid chromatography with tandem mass detection (ie, the LC/MS/MS method) (lower limit of quantification: 0.50 ng/ mL for valacyclovir and 9.93 ng/mL for acyclovir for the 250 mg study and 1.00 ng/mL for valacyclovir and 20.00 ng/ mL for acyclovir for the 1000 mg study). Pharmacokinetic parameters used for bioequivalence assessment were the area under the concentration-time curve from time zero to time of last non-zero concentration (AUC(0-t)) and from time zero to infinity (AUC(0-inf) and maximum observed concentration (C(max)). These parameters were determined from the valacyclovir concentration data using non-compartmental analysis. In the tained by analysis of variance (ANOVA) for valacyclovir were 107.54-124.26% for C(max), 95.45-103.46% for AUC(0-Inf) and 95.53-103.63% for AUC(0-t) whereas for acyclovir the 90% confidence intervals obtained were 103.19-117.02% for C(max), 99.61-106.92% for AUC(0-Inf) and 99.58-106.94% for AUC(0-t). In the study with valacyclovir 1000 mg formulations, the 90% confidence intervals obtained for valacyclovir were 93.20-107.35% for C(max), 90.87-96.27% for AUC(0-inf) and 90.87-96.27% for AUC(0-t) whereas for acyclovir the 90% CIs obtained were 95.98-104.94% for C(max), 97.13-103.94% for AUC(0-inf) and 97.14-104.09% for AUC(0-t). All the 90% confidence intervals obtained for all the parameters assessed were within the predefined range (80-125%). Based on these results, it can be concluded that the evaluated formulations are bioequivalent in terms of rate and extent of absorption.

Mycophenolate mofetil 500-mg tablet under fasting conditions: single-dose, randomized-sequence, open-label, four-way replicate crossover, bioequivalence study in healthy subjects.

BACKGROUND: Mycophenolate mofetil (MMF), a prodrug of mycophenolic acid (MPA), is an immunosuppressive agent indicated for the prophylaxis of organ rejection in allogeneic kidney, heart, or liver transplant recipients. The European regulatory authorities require bioequivalence studies for the marketing of generic products. OBJECTIVE: The aim of this study was to assess the bioequivalence of a generic (test) and branded (reference) formulation of MMF 500 mg and MPA. METHODS: This single-center, single-dose, randomized, open-label, 4-way crossover study was conducted at Anapharm's Clinical Research Facility, Québec, Québec, Canada. Healthy volunteers aged 18 to 55 years were eligible. Subjects were assigned to receive, in randomized order, a single dose of the test and reference formulations of MMF 500 mg under fasting conditions. Because the study design was 4-way replicate, there were 2 test periods and 2 reference periods. The 4 study periods were each separated by a 14-day washout period. Blood samples were collected over a period of 12 hours after administration for the determination of MMF pharmacokinetic properties, and over 48 (+/-0.5) hours, for MPA properties. Concentrations of the analytes were determined by reverse LC and detected using LC-MS/MS. Pharmacokinetic parameters were calculated from MMF and MPA concentration data using noncompartmental analysis. C(max) and AUC(0-t) were the primary evaluation criteria, while AUC(0-infinity) was a secondary parameter. The drugs were to be considered bioequivalent if the 90% CIs for the test/reference ratios of natural logarithm-transformed values of these parameters (obtained using ANOVA) were between 80% and 125%, per European regulations for bioequivalence. Tolerability was monitored using physical examination, including vital sign measurements, laboratory analysis, and adverse-events (AE) monitoring (including patient interview). RESULTS: A total of 103 subjects were enrolled (64 men, 39 women; 101 white, 2 black; mean [SD] age, 38 [10] years; weight, 68.2 [9.1] kg). The 90% CIs were as follows: MMF, C(max), 85.94% to 106.63%; AUC(0-t), 91.94% to 102.20%; and AUC(0-infinity), 93.15% to 105.48%; MPA, C(max), 92.03% to 105.82%; AUC(0-t), 97.42% to 100.59%; and AUC(0-infinity), 96.96% to 100.90%. These values met with the regulatory definition of bioequivalence. A total of 148 AEs were reported (68 in subjects who received the test treatment and 80 in subjects who received the reference treatment). The most commonly reported AEs were procedural pain (13/102 [12.7%] and 10/101 [9.9%] with the test and reference formulations, respectively), procedural site reaction (12 [11.8%] and 4 [4.0%]), and somnolence (7 [6.9%] and 14 [13.9%]). CONCLUSIONS: The generic and branded formulations of MMF 500 mg met the European regulatory criteria for assuming bioequivalence, based on the rate and extent of absorption of a single dose under fasting conditions. Both formulations were well tolerated in these healthy volunteers.

Results of a single-center, single-dose, randomized-sequence, open-label, two-way crossover bioequivalence study of two formulations of valsartan 160-mg tablets in healthy volunteers under fasting conditions.

BACKGROUND: Valsartan is a nonpeptide, orally active angiotensin II type 1 receptor blocker used to treat hypertension alone or in combination with other antihypertensive agents. OBJECTIVE: The aim of this study was to compare the relative bioavailability of a new valsartan 160-mg formulation (ie, test drug) and that of a reference formulation so that bioequivalence could be assessed, as required by European regulatory authorities for the marketing of a generic product. METHODS: This was a single-center, single-dose, randomized-sequence, open-label, 2-way crossover study with a minimum washout period of 7 days; drug was administered to healthy volunteers under fasting conditions. Blood samples were collected up to 36 hours postadministration, and valsartan levels were gauged from plasma by reverse liquid chromatography and tandem mass spectrometry detection (ie, the LC-MS/MS method). Pharmacokinetic parameters were calculated from valsartan concentration data using noncompartmental analysis. AUC(last), AUC(infinity), and C(max) were analyzed. The 90% CIs of the ratios of the test-versus-reference pharmacokinetic parameters (AUC(last), AUC(infinity), and C(max)) were obtained by ANOVA on ln-transformed data. The 90% CIs were required to be within 80.00% to 125.00% of the 90% CI to meet the criteria for bioequivalence. Tolerability was monitored using physical examination (including vital-sign measurements) and ECG performed at screening, as well as laboratory analysis, including biochemistry tests, hematology tests, and urinalysis, which were performed at screening and during the study period. RESULTS: Thirty-eight white (90.5%), 2 black (4.8%), and 2 Hispanic subjects (4.8%) enrolled in the study; the sample included a total of 27 men and 15 women. The mean (SD) age was 37 (11) years and mean weight was 65.4 (7.6) kg. The 90% CI values for pharmacokinetic measurements were as follows: AUC(last), 94.45% to 118.59%; AUC(infinity), 93.58% to 116.51%; and C(max), 93.61% to 122.02%. Thus, they were all within the predefined 80.00% to 125.00% range. Thirty-six postadministration adverse events were reported; the most common was blood pressure decrease. A decrease of blood pressure was experienced by 6 subjects (14.6%) after the administration of the test formulation, and by 5 subjects (12.5%) after the administration of the reference formulation. Thirty-three of these adverse events were graded as mild and 3 as moderate; 11 were judged as probably related, 12 as possibly related, 3 as remotely related, and 10 as unrelated to the study medication. CONCLUSIONS: In this open-label study of healthy volunteers, the test and reference formulations of valsartan 160 mg met the European regulatory definition of bioequivalence, based on the rate and extent of absorption of a single dose under fasting conditions. Both formulations were well tolerated.

Bioequivalence study of two different film-coated tablet formulations of losartan-hydrochlorothiazide in healthy volunteers.

The study was conducted in order to assess the bioequivalence of two film-coated formulations containing 100 mg of losartan (CAS 124750-99-8) and 12.5 mg of hydrochlorothiazide (CAS 58-93-5). Seventy-three healthy subjects were enrolled in a randomised, single-dose, open-label, two-way crossover study, with a minimum washout period of 7 days. A total of 21 blood samples were collected up to 36 h post-dosing. Losartan, losartan carboxy acid and hydrochlorothiazide levels were determined by liquid chromatography with tandem mass detection (lower limit of quantification: 1.01 ng/mL for hydrochlorothiazide, 2.02 ng/mL for losartan and 2.51 ng/mL for losartan carboxy acid). Pharmacokinetic parameters used for bioequivalence assessment (AUC(0-t) and Cmax as primary and AUC(0-inf) as secondary pharmacokinetic parameters) were determined from the losartan and hydrochlorothiazide concentration data using non-compartmental analysis. Data from losartan carboxy acid was reported and presented as supportive data. The 90% confidence intervals (obtained by ANOVA) for losartan were 97.05-118.48% for Cmax 100.76-106.10% for AUC(0-t) and 100.80-106.10% for AUC(0-inf) whereas for hydrochlorothiazide the 90% confidence intervals obtained were 103.94-115.33% for Cmax, 101.97-109.61% for AUC(0-t) and 101.77-109.02% for AUC(0-inf), and for losartan carboxy acid the intervals obtained were 98.31-107.82% for Cmax, 97.89-104.30% for AUC(0-t) and 98.06-104.30% for AUC(0-inf). All the 90% confidence intervals obtained for all the parameters assessed were within the predefined ranges (80-125%). Based on these results, it can be concluded that the evaluated formulations are bioequivalent in terms of rate and extent of absorption.

Bioequivalence study of two letrozole tablet formulations. Single dose, randomized, open-label, two-way crossover bioequivalence study of letrozole 2.5 mg tablets in healthy volunteers under fasting conditions.

The study was conducted in order to compare the bioavailability of two tablet formulations containing letrozole 2.5 mg (CAS 112809-51-5). Twenty healthy subjects were enrolled in a single-centre, bioequivalence, randomised, single-dose, open-label, two-way crossover study, performed under fasting conditions with a minimum washout period of 21 days. Plasma samples were collected up to 240 h post-dosing. Letrozole levels were determined by reverse liquid chromatography and detected by tandem mass spectrometry detection, LC/MS/MS method. Pharmacokinetic parameters used for bioequivalence assessment, area under the concentration-time curve from time zero to time of last non-zero concentration (AUC(0-t)) and from time zero to infinitive (AUC(0-inf)) and maximum observed concentration (Cmax), were determined from the letrozole concentration data using non-compartmental analysis. The 90% confidence intervals obtained by analysis of variance were 90% geometric confidence Intervals of the ratio (A/B) of least-squares means from the analysis of variance (ANOVA) of the In-transformed AUC(0-t), and Cmax was within 80% to 125%. Bloequivalence between formulations was concluded both in terms of rate and extent of absorption.

Bioequivalence study of two tablet formulations of sildenafil.

This study was conducted in order to assess the bioequivalence of two tablet formulations containing 100 mg sildenafil (1-[4-ethoxy-3-(6,7-dihydro-1-,ethyl-7-oxo-3-propyl-1H-pyrazolo[4,3-d]pyrimidin-5-yl)phenylsulphonyl] -4-methyl piperazine, CAS 139755-83-2). Twenty-eight healthy subjects were enrolled in a single-centre, randomised, single-dose, open-label, 2-way crossover study, with a minimum washout period of 7 days. Plasma samples were collected up to 18.0 h postdosing. Sildenafil levels were determined by reverse liquid chromatography coupled with tandem mass spectrometry detection (LC-MS/MS). Pharmacokinetic parameters used for bioequivalence assessment [area under the concentration-time curve from time zero to time of last non-zero concentration (AUC(last)) and maximum observed concentration (C(max)) were main evaluation criteria; however, the area under the concentration-time curve from time zero to infinity (AUC(inf)) was also analysed] were determined from the sildenafil concentration data using non-compartmental analysis. The 90% confidence intervals (obtained by analysis of variance, ANOVA) were 86.70-108.19 for C(max), 86.67-99.26 for AUC(last) and 87.19-99.82 for AUC(inf) within the predefined ranges. Bioequivalence between the two formulations was concluded both in terms of rate and extent of absorption.