ABSTRACT:
Matrix tablets Diclofenac sodium were formulated consisting of polymers such as polyethylene oxide (PEO) Mw 900,000 and sodium alginate in combination with different ratios by direct compression and wet granulation method with an aim to attain zero order release after the initial burst release and compare the of release kinetics of the drug from matrices prepared from wet granulation and direct compression method. Preformulation studies were carried out to investigate drug polymer interaction. This was done by carrying out Differential scanning calorimetry (DSC). FTIR spectra revealed that there was no shift in the peaks for pure drug and the selected polymers in the formulation indicating that there was no interaction between drug and the polymers. Matrix tablets were subjected to in-vitro drug release in 0.1N HCl pH 1.2 for 2 hrs followed by phosphate buffer pH 7.4 for remaining hours. In-vitro dissolution kinetics followed zero order drug release from (F6) formulation containing (drug: 30% PEO: 30% sodium alginate) which may be due to constant diffusional path length. Analysis of variance showed a significant difference (p>0.05) in drug release among the formulations. SEM study confirmed both diffusion and erosion mechanisms to be operative during drug release from the optimized batch of matrix tablet. Thus best formulation F6 (DC) prepared by direct compression exhibited almost similar drug release profile in different dissolution media as that of the marketed product F7 and prolonged the release for more than 10 hrs. The obtained best formulation showed good stability and satisfactory preclinical anti-inflammatory activity. Therefore the blend of hydrogels in appropriate proportions can release the drug for prolonged period of time. Hence polymer blend of PEO and sodium alginate are ideal for formulating controlled release, cost effective matrix tablets.