| With a goal of developing optimal controlled release formulation with minimum expenditure of material and maximum possible reproducibility of results, solid dispersion technique using solvent evaporation method was implied. This study was undertaken to develop multiple strength (50mg, 75mg and 100mg) controlled release formulation of Diclofenac sodium.;Drug and polymers were dissolved separately in a various weight ratios using a mixture of ethanol to form clear solutions. These solutions were then mixed, stirred, and evaporated under the gentle stream of nitrogen at 40°C. The dispersion mixture was then further dried overnight in an oven at 40°C. The dried residue was sieved through No.60 mesh screen and stored.;In-vitro dissolution studies were carried out for 24 hours period using the United States Pharmacopoeia dissolution apparatus I method. A commercially marketed product, Diclofenac sodium®ER 100mg was used as a control for comparison purposes. Among the formulations evaluated, the sample containing Drug: Methocel at a weight ratio of (1:1.5) gave the desired dissolution profiles of drug from 50 mg, 75 mg and 100 mg strength dosage forms.;The drug release vs. time from these formulations was observed to be directly proportional to the dosage strength. And, when these data were plotted as % drug release vs. time, similar overlapping graphs were obtained, proving that the release pattern from all formulation remained the same irrespective of the dosage strength. Furthermore, dispersion samples were stored at room temperature and at 40°C for 1 month, and tested for drug release profiles and showed no change in drug release.;In addition, the preliminary evaluation of the physical characteristics of the formulation powder via X-ray diffraction and Differential Scanning Calorimetric studies supports that there are no chemical interactions within the formulation ingredients.;A single solid dispersion of Diclofenac sodium containing Drug/Methocel at a weight ratio of 1:1.5 provided a suitable drug powder for its direct use in the product development of multiple strengths tablet dosage forms. Using this simple formulation approach, it is possible to minimize the expenses and formulation work associated with the development of individual multiple strength dosage forms of this drug. |
