Acta Pharm. 51 (2001) 233-239
The effects of varying concentrations of polyethyleneglycol 4000 (PEG 4000) or sodium lauryl sulphate (SLS) on the release of hydrochlorothiazide (HCTZ) embedded in the dika fat (a hydrogenated vegetable fat) matrix were investigated. Hydrochlorothiazide granules containing dika fat, dicalcium phosphate (Ditab ®), and either of the surfactants were prepared using the fusion method. The presence of PEG 4000 enhanced the release of HCTZ probably due to the modification of the barrier properties of dika fat brought about by increased wetting, reduction in interfacial tension and contact angle of the granules. The presence of SLS, on the other hand, resulted in retardation of HCTZ release from the dika fat matrix. This was attributed to possible complex interaction between either the fatty acid components of dika fat, and hydrolytic products of SLS in 0.1 mol L-1 hydrochloric acid or between these hydrolytic products and HCTZ. Sodium lauryl sulphate may not be suitable as a drug release enhancer when a vegetable oil or wax such as dika fat is employed as the matrix because of a possible retardation of the release of the drug in acidic environment of the stomach.
Keywords: dika fat, barrier properties, surfactants, micelles, hydrochlorothiazide