Preparations of Prazosin Hydrochoride Suppositories as a Hospital Pharmacy Manufactured Product

Abstract

For use in hypertensive emergency, 2 types of prazosin hydrochloride (PRZ) suppositories were prepared with Witepsol H-15 and polyethylene glycol (PEG) as typical lipophilic and hydrophilic bases respectively. The suppositories were used for in vitro release and in vivo bioavailability
In in vitro test, the Witepsol suppository released slowly 80% of PRZ content for 5 hr. The release rate of PRZ from the PEG suppository was rapid compared to that from the Witepsol suppository (almost 100% for 2.5 hr).
Contrary to the in vitro release, PRZ plasma concentration curves in rabbits for the Witepsol suppository showed better absorption profile than for the PEG suppository, suggesting higher clinical applicability of the Witepsol suppository. It was also emphasized that in vivo bioavailability test is essential for selection of suitable suppository base from those of which physicochemical properties widely differ.