DETERMINATION OF pK_a VALUES OF SOME BUTYROPHENONES, THEIR SENSITIVE LC-UV ANALYSIS IN PHARMACEUTICAL DOSAGE FORMS AND STRESS DEGRADATION BEHAVIOR UNDER ICH-RECOMMENDED STRESS CONDITIONS

Abstract

In this study, pK_a values of some ionizable butyrophenones, namely, benperidol, droperidol, and haloperidol were determined using by the dependence of the retention factor on pH of the mobile phase. The effect of the mobile phase composition on the ionization constant was studied by measuring the pK_a at different methanol–water mixtures, ranging between 50 and 65% (v/v) using an LC-UV method. Additionally, a simple, accurate, precise, and fully validated analytical method for the simultaneous and individual determination of benperidol, droperidol, and haloperidol in their dosage forms was developed. Butyrophenones were exposed to thermal, photolytic, hydrolytic, and oxidative stress conditions, and the stressed samples were detected by the proposed method.

Keywords:

• benperidol
• degradation
• droperidol
• haloperidol
• liquid chromatography
• pK_a values

Notes

*Each value is the mean of three experiments.