FORMULATION DEVELOPMENT OF ISOXSUPRINE HYDROCHLORIDE MODIFIED RELEASE MATRIX TABLETS

The objective of the present investigation was to study the effect of critical formulation parameters affecting release of isoxsuprine hydrochloride from matrix tablets using combination of polyethylene oxide (PEO) and dicalcium phosphate (DCP). The powder blend consisting of drug and excipients was analyzed for angle of repose, Carr’s index and Hausner’s ratio. The tablets were prepared by direct compression method. To assess the compressional behavior of the drug-excipient blend, the tablets were analyzed for friability and crushing strength. The in vitro drug release study was carried out in distilled water. The powder blend exhibited satisfactorily flow as measured by angle of repose, Carr’s index and Hausner’s ratio. The formulation ingredients showed satisfactory tableting properties (friability <1%, crushing strength ≥ 4 kgf).  The drug release was modified on addition of PEO and DCP. Addition of 5 to 25% DCP in the formulation of matrix tablets caused apparent difference in the drug dissolution in distilled water. However, the difference was insignificant as analyzed by analysis of variance (ANOVA) and similarity factor ( f₂). The drug release from the tablets was best explained by Weibull model. Unified Weibull model was evolved to predict drug release from the formulated batches. The findings of this investigation can be extended to industry to cut down the cost of formulation and to by-pass the existing patents employing hydrophilic matrixing agents, at least for selective drugs.