Generic Substitution and Bioequivalence of Sodium Valproate at Steady-State in Healthy Volunteers

Abstract

The objective of this study was to investigate the bioequivalence of three marketed formulations of sodium valproate 500mg enteric-coated tablets at steady-state in healthy, adult male human subjects in a multiple-dose cross-over study. Sodium valproate tablets were administered twice daily for four days and only the morning dose was administered on the fifth day during each period. Blood samples were collected pre-dose on days 1–5, and post-dose on day 5 over 12 hours in each period. Plasma concentrations were determined using a validated high performance liquid chromatography method. Both Encorate and Epilex (generic products) were bioequivalent to Vaparin (reference product) and all three products were well tolerated by all subjects.

Keywords:

• Sodium Valproate
• Generic
• Bioavailability
• Narrow Therapeutic Index

ACKNOWLEDGEMENT

The research was supported by a grant provided by Ranbaxy Research Laboratories, Gurgaon, India for a Ph.D. program run in collaboration with Jamia Hamdard University, New Delhi. The authors would like to thank the staff of Ranbaxy Clinical Pharmacology Unit for their support to the conduct of this study.