Bioavailability of a film-coated tablet of valproate in nonfasting volunteers.

The bioavailability of a film-coated tablet of valproate (VPA) in nonfasting volunteers was studied. Ten healthy adults received a single 200 mg (mean 3.55 mg/kg) film-coated tablet, 15 minutes after breakfast. Venous blood was then taken at regular intervals of up to 4 or 7 hours after the dosage, and the serum VPA concentrations were determined by means of a fluorescence polarization immunoassay. VPA was slowly absorbed with the peak concentrations occurring 1.5 to 4 hours after the administration. The mean concentration (Cmax) and extent of absorption (area under the concentration-time curve) between 1 and 4 hours were 22.2 micrograms/ml and 59.3 micrograms.h/ml, respectively. It was concluded that Cmax with a film-coated tablet of VPA can be detected if blood is taken at around 3 hours after the dosage under nonfasting conditions.