DEVELOPMENT OF DICLOFENAC SODIUM CONTROLLED-RELEASE SOLID DISPERSIONS BY SPRAY-DRYING USING OPTIMIZATION STRATEGY .1. POWDER FORMULATION

Diclofenac sodium (DS) controlled release solid dispersions were prepared by spray drying using ethylcellulose (EC), methacrylic acid copolymer (Eudragit), chitosan, hydroxypropyl methylcellulose (HPMC), and carbomer as single carriers and EC-chitosan as combined carriers. Among solid dispersions of 3:1 drug:single carrier, the system containing chitosan exhibited the slowest dissolution followed by the systems containing Eudragit, EC, HPMC, and carbomer, respectively. Combined carriers of EC-chitosan exhibited more dissolution retarding effect than single carrier of EC or chitosan. An Hadamard matrix H[8] was employed to estimate the main effects of four parameters: spray feeding volume and contents of absolute ethanol, EC, and chitosan. Optimization strategy using multiple linear regression and a feasibility computer program was utilized to obtain the optimum quantities of the four parameters that would result in a required DS controlled release solid dispersion. The validation of the optimum DS solid dispersion was confirmed by statistical analysis. The optimized 10:(2.5+0.02) DS:(EC+chitosan) controlled release solid dispersion exhibited a dissolution profile that was well fitted to Higuchi model.