Preparation and in vitro evaluation of solid dispersions of halofantrine

The low aqueous solubility of halofantrine (HF) and its low bioavailability from commercially available tablets (Halfan) suggested the formulation of solid dispersions (SDs) of HF to reduce its particle size and improve its wettability and aqueous solubility. Preformulation studies involved the development of a high performance liquid chromatography (HPLC) method for the analysis of HF. In addition, solubility studies were conducted on HF in aqueous solutions containing different concentrations of various carriers. Formulation studies included the preparation of SDs and physical mixtures (PMs) of HF with different carriers and their physicochemical characterization using differential scanning calorimetry (DSC), Fourier-Transform infra-red (FT-IR) spectroscopy and dissolution studies. A 3-month stability study at elevated temperatures was conducted on representative SDs of HF with selected carriers.