Design and Evaluation of Guar Gum Based Controlled Release Matrix Tablets of Zidovudine

In the present investigation an attempt was made to formulate the oral controlled release zidovudine matrix tablets by using Guar gum as rate controlling polymer and to evaluate drug release parameters as per various release kinetic models. The tablets were prepared by wet granulation method. Granules were prepared and evaluated for loose bulk density, tapped density, compressibility index and angle of repose, shows satisfactory results. All the granules were lubricated and compressed using 12.6 mm flat faced punches. Compressed tablets were evaluated for uniformity of weight, content of active ingredient, friability, hardness, in vitro release studies and swelling index. All the formulations showed compliance with Pharmacopoeial standards. The in vitro dissolution study was carried out for 12 hours using paddle (USP type II) method in phosphate buffer (pH 6.8) as dissolution media. Formulation F-1 failed to sustain release beyond 10 hours. Among all the formulation, F-2 shows 95.97% of drug release at the endof 12 hours. Selected formulation (F-2) was subjected to stability studies for 3 months, which showed stability with respect to release pattern. Fitting the in vitro drug release data to Korsmeyer equation indicated that diffusion along with erosion could be the mechanism of drug release.