Abstract

One of the important methods to improve the solubility of a less water-soluble drug is by the use of co solvents. The solubility enhancement produced by two binary blends with a common co solvent (water-propylene glycol and propylene glycol-ethyl acetate) was studied against the solubility parameter of solvent blends (δ1 ) to evaluate the solubility parameter of drug (δ2 ). The binary blend water:propylene glycol (20:80) gave maximum solubility with an experimental δ2 value of 16.52 (Cal/cm 3 ) 0.5 that was comparable to the theoretical value of 16.52 (Cal/cm 3 ) 0.5 determined by molar volume method and 16.35 (Cal/cm 3 ) 0.5 when determined by method proposed by Lin and Nash. The solvent blend water:propylene glycol (20:80) in which the drug exhibited maximum solubility was used as the reconstituting medium for formulation of dry suspension of cefaclor. The percentage cumulative drug release of cefaclor from the formulation F7 was compared to the marketed formulation by calculating the f 1 (dissimilarity factor) and f 2 (similarity factor) factors. A higher f 1 value and f 2 value below 50 indicates difference between the two dissolution profiles.