Preparation and in vitro evaluation of suppositories of halofantrine hydrochloride

Abstract

Halofantrine (HF) hydrochloride is commercially available only as oral dosage forms. Limitations of oral dosing of the drug coupled with non-availability of the safe parenteral preparations prompted the need to develop and evaluate suppository HF formulations, which may serve as a practical alternative. The effects of type of suppository base and incorporation of non ionic surfactants on in vitro release characteristics of HF from suppositories were investigated. The release rates were determined using a modification of the continuous flow bead-bed dissolution apparatus for suppositories. The results showed that the drug release from water-soluble base (polyethylene glycol) was significantly greater than that from lipophilic bases (Shea butter and Witepsol H15) (P surfactants (Tweens 20 and 80, Spans 20 and 60) at different concentrations did not improve the in vitro availability of the drug from composite polyethylene glycol base (1500:4000, 80:20, w/w) suppositories. The extent of drug release was very low (maximum of 2.3%) It is suggested that further studies are required for development of modalities to enhance the release of halofantrine from polyethylene glycol suppositories so as to optimize this dosage formulation of the drug.