Design and Evaluation of a Sustained Release Enteric Coated Dosage Form of Fluoxetine Hydrochloride

The purpose of present study was to develop once a day sustained release enteric coated tablet of Fluoxetine HCl by direct compression method. Design was prepared for nine batch using fenugreek mucilage at 40%, 50% and 60% concentration ; HPMC at 10%, 15% and 20%; Compritol ATO 888 at 10%, 15% and 20% and ethyl cellulose at 2%, 3% and 4% concentration. Fenugreek mucilage was extracted from dried ripe seeds of Trigonella foenum-graecum (Fabaceae). Cellulose acetate phthalate was used as enteric coating agent. The tablets were characterized for weight variation, crushing strength, friability, drug content and in vitro drug release study. All the formulations were complied with standard specifications. The Drug excipients compatibility study was performed by DSC and IR Spectroscopy and no incompatibility was found. The results of in vitro dissolution studies indicated that formulations X2, X5 and X8 released 7.03%, 7.03%, 4.75% of Fluoxetine respectively at the end of 2 hour and 98.17%, 78.12%, 65.45% of Fluoxetine respectively at the end of 24 hour. Increased release rate was observed in polymer in the order HPMC K 100M > ethyl cellulose > Compritol ATO 888. Formulation X2 (50% fenugreek mucilage and 15% HPMC K 100M) could extend drug release up to 24 hour and it exhibited satisfactory drug release within first 2 hours and total release pattern was very close to marketed product. The mechanism of drug release was found to be diffusion coupled with erosion. Optimized formulation was found to be stable when exposed to 400C/ 75 % of relative humidity for 3 month