entrapment efficiency.

The aim of this study was to prepare Diclofenac potassium (DP) microspheres by using Double Emulsion-solvent evaporation method with ethyl cellulose (EC) and Eudragit polymers. An attempt was made to formulate a sustained release dosage form of diclofenac potassium, to minimize frequent dosing as well as reducing or eliminating local side effects by avoiding the drug release in the upper gastro-intestinal tract Poly vinyl alcohol containing 2% (w/w) span 80 was the external phase and polymer -drug solution was the internal phase. EC and Eudragit were used to encapsulate diclofenac potassium. By using different formulation variables, six different formulations (F1, F2, F3, F4, F5, & F6) were prepared. The resulting microspheres obtained, were more spherical in shape and showed more entrapment efficiency. The size of the microspheres varied between 346-695 μm and as high as 96.24% loading efficiency for Eudragit and 82.34% for EC was obtained. In vitro release study was carried out in 0.1 N hydrochloric acid solution (pH 1.2) for first 2 hours followed by in phosphate buffer solution (pH 6.8) for next 4 hours. After first 2 hours of dissolution in 0.1 N hydrochloric acid, EC microspheres released 23% of drug and Eudragit released 7% of drug. The formulations were found to be effective in providing controlled release of drug for a longer period of time.

The sustained release of Baclofen is desired because of its short biological half-life. Microspheres of Baclofen were prepared using the non-aqueous emulsification solvent evaporation method. The impacts of different factors such as type of Eudragit polymer as matrix polymer, Eudragit: HPMC K4M ratio on the characteristics of the microspheres were investigated. The morphology of microspheres was studied using optical and scanning electron microscopy and it was shown that microspheres had a spherical shape and smooth surface. The percentage yield of microspheres of all formulation was in the range of 94.01% to 99.12%. The drug content determination showed that even if the polymer composition was changed the solvent evaporation process was highly efficient to give microspheres having maximum drug loading. In termination, the prolonged sustained release time and enhanced stability resulting from the Baclofen microspheres might make contribution to its use.