Valacyclovir is a prodrug of acyclovir. In Mexico, it is indicated for the treatment of herpes zoster and herpes\r\nsimplex infections. The aims of these 2 studies were to compare the bioavailability and to determine the bioequivalence\r\nof 2- test formulations containing 500 mg and 1000 mg of oral valacyclovir. Two separate, single-dose, open-label,\r\nrandomized, 2-period, crossover studies were conducted. For each study a different set of 26 subjects of both\r\ngenders was enrolled, with a 7-day washout period. In both studies, the study formulations were administered\r\nafter a 10-hour overnight fast. For pharmacokinetic analysis, blood samples were drawn at baseline, 0.25, 0.50,\r\n0.75, 1, 1.25, 1.50, 1.75, 2, 3, 4, 6, 8, 12 and 24 hours after administration. Plasma concentrations of acyclovir\r\nwere determined using HPLC coupled to a fluorescence detector. The test and reference formulations were to be\r\nconsidered bioequivalent if the 90% CI for the geometric mean test/reference ratios were within a predetermined\r\nrange of 80% to 125%. In the study with valacyclovir 500 mg, the 90% CI were 95.24% - 115.33% for Cmax, 96.20%\r\n- 103.55% for AUC0-t, 97.12% - 104.34% for AUC0-8. In the study with valacyclovir 1000 mg the 90% CI were 86.22%-\r\n100.87% for Cmax, 89.11% - 98.50% for AUC0-t, 89.00% - 98.34% for AUC0-8. In both studies, a single dose of the test\r\nformulation met the regulatory requirements to assume bioequivalence, based on the rate and extent of absorption.
Loading....