Release modulation of highly water soluble drug using solid dispersion: impact of dispersion and its compressed unit

Abstract

In present day, availability of various carriers, innovative techniques of production and plenty of solvents support the growth of solid dispersion (SD) technology in pharmaceutical industries to overcome many issues. The present study was aimed to develop SD based sustained release system of Milnacipran HCl (MH). The SD containing ethyl cellulose, Eudragit RLPO and Eudragit RSPO at drug–polymer ratios of 1:1, 1:2, and 1:3 were developed using solvent evaporation technique and different waxes at ratio of 1:1, 1:1.25, 1:1.5 and 1:1.75 with drug were developed by melting method. The physicochemical properties of SD were evaluated using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The desired SD batch was further compressed into tablet unit to achieve predetermined once a day drug release. Tablets prepared were evaluated for physicochemical parameters, in vitro drug release, drug release kinetics and scanning electron microscopy. Out of selected carriers, bees wax had shown maximum release retardation. The results of FTIR, DSC and XRD studies exhibited poor interaction amongst MH–bees wax and retention of crystalline state of MH in SD system. The presence of Benecel® (HPMC K 200 M; 75 mg) in tablets comprising SD (1:1.25, MH:bees wax) revealed remarkable drug release extension and it was considered an optimal. The later was submitted to short term stability study and its results indicated the stable characteristic of system. Drug release from optimized formulation fitted well into Higuchi model with anomalous diffusion. The compressed unit of SD system of highly water soluble drug can be successful single day regimen.