In vitro evaluation of cumulative release of valproic acid and vitamin E from hexadecanol microspheres. Part 2: Antiepileptic agents.

Hexadecanol microspheres were investigated as a vehicle for the controlled release of valproic acid. Microsphere of the antiepileptic agent were prepared by the meltable dispersion method in water using wetting agents. To prevent hepatotoxicity, microspheres containing both the drug and vitamin E were also prepared. The method in simple, inexpensive, rapid and reproducible. The drug release was evaluated in vitro. Kinetic results were analyzed to distinguish between the first-order release model and the square root of time relationship. More than 99% of the isolated microspheres were particle size range 200-710 microns. The average drug content was 24%. Drug bioavailability was greatly affected as a result of microspheres formation.