Design and evaluation of extended release analgesic oral dosage form

Abstract

Acetaminophen (N-Acetyl-p-Amino: APAP) of 650 mg dosage unit sachets was formulated as dry mixture of, microspheres containing the active ingredient, and pure powder form of drug in order to obtain an oral extended drug delivery system. The sachet form consists of a combination of 69% Acetaminophen as immediate release and 31% as extended release product in the form of microspheres. The immediate release portion which is pure drug in powder form was blended with sweetening agents, flavors and effervescent agents to mask the unpalatable taste. Microspheres containing the active medicament 31% were prepared by using drug and polymeric material Eudragit L100 in the ratio of 1:1, 1:1.5, 1:2 and drug and Eudragit S100 in the ratio of 1:1, 1:1.5, 1:2 and drug and combination of Eudragit L100 and Eudragit S100 in the ratio of 1:0.5:0.5, 1:0.75:0.75, 1:1:1 by solvent evaporation method. The dissolution profile of each sachet indicated 60% dissolution of active medicament at the end of 1 h. Remaining 40% of drug dissolution was complete over a period of 8 h. Dissolution profile exhibits that one sachet unit of acetaminophen 650 mg blend is available for a period of 8 h providing an analgesic therapeutic activity in the treatment of chronic arthritis.