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. INTRODUCTION: Isoxsuprine hydrochloride is structurally a novel vasodilator . The short biological half-life (5±2 hr) and the fast clearance make the drug, a suitable candidate for the development of modified release formulation. Furthermore, the drug is required to be taken for a long period by the patients. The use of modified release formulation is associated with less nausea and dizziness at the initiation of therapy. Hence, to improve the patient compliance as well as to reduce side effects, the drug needs to be formulated in modified release dosage form. Hydrophilic polymer matrix systems are widely used in oral modified drug delivery because of their flexibility to obtain a desirable drug release profile, costeffectiveness, and broad regulatory acceptance 2, . These dosage forms are designed to deliver the drug at a modified and predetermined rate, thus maintaining a therapeutically effective concentration of the drug in the systemic circulation for a long period of time and therefore reducing the frequency of dosing and improving patient compliance 4, . Hydrophilic polymers such as hydroxylpropyl methylcellulose (HPMC), sodium carboxymethylcellulose, Carbopols and Correspondence to Author: