Validasi metode analisis asam valproat yang diderivatisasi dengan 2,4-dibromoasetofenon dalam plasma manusia in-vitro secara kromatografi cair kinerja tinggi photo diode array dan aplikasinya secara in-vivo = Analysis method validation of valproic acid in human plasma in vitro after derivatization with 2,4-dibomoacetophenon by high performance liquid chromatography photo diode array and application in-vivo