Design and Evaluation of Ethyl Cellulose Based Matrix Tablets of Ibuprofen with pH Modulated Release Kinetics

Abstract

Controlled release preparations have been reported to reduce the gastro irritant and ulcerogenic effects of non steroidal antiinflammatory drugs. In the present study, an attempt was made to develop matrix tablet-based controlled release formulations of ibuprofen, using ethyl cellulose as the rate-controlling polymer. In order to prevent initial release of the drug in the acidic environment of the stomach, cellulose acetate phthalate was incorporated in the matrix in varying amounts. It was found that with increasing the proportion of ethyl cellulose in the matrix, the drug release was extended for 14-16 h. Incorporation of cellulose acetate phthalate in ethyl cellulose matrix provided very low initial release of the drug in the first 2-3 h followed by enhanced release rate in alkaline medium owing to the high solubility of cellulose acetate phthalate at basic pH which led to creation of a porous matrix. It was concluded that combination of cellulose acetate phthalate with ethyl cellulose in the matrix base can be an effective means of developing a controlled release formulation of ibuprofen with very low initial release followed with controlled release up to 14-16 h.

Keywords: Ibuprofen; cellulose acetate phthalate; ethyl cellulose; matrix tablet.

Fig. 1

Release profile of ibuprofen from batches with varying EC content Release profile of ibuprofen from batches with varying EC content, IE1C0- 12.5% (–●–), IE2C0- 25%(–■–), and IE3C0- 50%(–▲–) w/w of drug. Each data point represents mean±SD of n = 6.

Fig. 2

Release profile of ibuprofen from formulations Release profile of ibuprofen from formulations containing A: 12.5% w/w EC with varying CAP content, IE1C0- 0%(–●–), IE1C2- 25%(–■–), IE1C3- 37.5%(–▲–) w/w of drug and B) containing 25% w/w EC with varying CAP content IE2C0- 0%(–●–), IE2C3- 37.5%(–■–), IE2C4- 50%(–▲–) w/w of drug. Each data point represents mean ± SD (n = 6).

Fig. 3

Release profile of ibuprofen from the formulations IE1C3 and IE2C4 Release profile of ibuprofen from the formulations A. IE1C3 and B. IE2C4 showing the effect of simulated GI pH (without enzymes) without surfactant (–■–), with 1% v/v Tween 80 (–●–) and with 0.5%w/v SLS (–▲–). Each data point represents mean ± SD (n = 6).