Stability of the tranquilizer drug propionylpromazine hydrochloride in formulated products

An analytical method to evaluate propionylpromazine hydrochloride (PPZHCl) in tranquilizer formulations was developed using high‐performance liquid chromatography (HPLC). During analysis of aged quality‐control samples, a previously unreported chromatographic response was observed at a shorter retention time than PPZHCl. Further investigation of formulations stored in trap tap devices at temperatures ranging from 5 to 40 °C during field trials at four different locations confirmed the degradation of the active ingredient. Further investigation using HPLC/tandem mass spectrometry revealed two to five degradates, with the major degradates being oxidation products of the active ingredient, PPZHCl. As PPZHCl formulations must be stable when stored at 5 to 40 °C for 6 to 12 months, reformulation with the anti‐oxidant ascorbic acid was utilized to achieve the required PPZHCl stability. Copyright © 2005 Society of Chemical Industry