Formulation and Evaluation of Pharmaceutically Equivalent Parenteral Depot Suspension of Methyl Prednisolone Acetate

The aim of the present study was to formulate and evaluate pharmaceutically equivalent injectable aqueous suspension for parenteral depot of methyl prednisolone acetate. Various aqueous suspensions were prepared by rapid stirring and colloid milling method. The prepared aqueous suspensions were subjected to particle size determination, sedimentation study, in vitro release studies (pH dependent dissolution study), and stability studies. The optimized formulation consisted of 4% w/w of methyl prednisolone acetate, 2.91% w/w of PEG-3350, 0.19% w/v of injection grade Tween-80, 0.68% w/w of monobasic sodium phosphate, 0.15% w/w of di-basic sodium phosphate, 0.91% w/v of benzyl alcohol, 0.32% w/w sodium meta bisulphate. The f(2) value was calculated for innovator (DepoMedrol((®)), Batch No. MPH-0254) and optimized formulation at pH 6.8 and pH 7.4 phosphate buffers. The f(2) values of 62.94 and 54.37 were obtained at pH 6.8 and pH 7.4 phosphate buffers respectively. The particle size ranged 23-27 μm at D value of 0.9 for both test and innovator product.