Abstract:
Physical mixtures (PMs) of atorvastatin and four different hydrophilic swellable polymers (pregelatinized starch, hydroxypropyl methyl cellulose, poloxamer 407 and sodium carboxy methyl cellulose) were prepared at 1:0.5, 1:1 and 1:2 ratios. In vitro dissolution study was performed in distilled water for 60 minutes at 50 rpm and 37±0.5°C. Faster dissolution was achieved using poloxamer at 1:2 ratios; it was 87% after first 10 minutes of dissolution. However, considering complete dissolution for 60 minutes, atorvastatin release was increased in the following order: pregelatinized starch > poloxamer 407 > hydroxypropyl methyl cellulose > sodium carboxy methyl cellulose. In case of all the batches, statistically significant correlation between % release and polymer concentration was observed (P ˂ 0.5, ANOVA single factor). Mean dissolution time (MDT), time for 25% release (t25), 50% release (t50) and 75% release (t75) were also calculated. Significant correlation was found between polymer concentration and corresponding mean dissolution time values (P˂ 0.5, ANOVA single factor). Highest MDT was 13.85 minute for pregelatinized starch and lowest MDT was 0.5 minute for poloxamer. Release data were fitted in different model and release was found to be fitted best in Korsmeyer-peppas model where fickian diffusion mechanism was predominant.

Keywords: Atorvastatin, Physical Mixing Technique, Hydrophilic Swellable Polymer, Fickian Diffusion.