Preformulation study on enhancing the solubility of albendazole

Abstract

For low aqueous solubility drugs, the challenge of making solid dispersions is in choosing the amount of carrier that would increase the aqueous solubility while keeping the overall oral dosage size small. Solubility parameters have been used to predict the solubility of drug in a carrier which in turn determines the extent of solubility in an aqueous medium. Solubility parameters alone are not enough and other parameters such as crystallinity index can also be used to improve the drug solubility during formulation. This study used solubility parameters and crystallinity index to select carriers which increased the aqueous solubility of albendazole (ABZ). Four polymers, Polyethylene Glycol 8000 (PEG), hydroxypropyl methyl cellulose (HPMC), polyvinyl pyrrollidine (PVP K90) and carboxymethyl cellulose (CMC), were used individually as carriers in various ratios with ABZ and formulated as solid dispersions using the solvent evaporation method. The results obtained showed that both solubility parameters and crystallinity index when used together indicated that the polymers and ABZ were miscible in each other. The solid dispersions formulated further showed increased ABZ solubility which was evident from reduced peak obtained from FT-IR spectra while dissolution tests confirmed increased dissolution of ABZ solid dispersions as compared to ABZ alone. PVP K90: ABZ solid dispersions showed the highest increase in dissolution rate as compared to solid dispersions of ABZ with HPMC and CMC.

Keywords: Solid dispersion, solubility parameter, Crystallinity Index