Eudragit-S, Eudragit-L and cellulose acetate phthalate coated polysaccharide tablets for colonic targeted delivery of azathioprine

Abstract

The present work deals with the formulation and evaluation of polymer-coated polysaccharide tablets of azathioprine prepared by direct compression method using different ratios of avicel (MCC), inulin and triacetin. The tablets formulations containing 25 mg of azathioprine were prepared and evaluated for thickness, hardness, friability, weight variation, content uniformity and in vitro dissolution test. Hardness and percentage friability were in the range of 7.23–7.43 kg/cm² and 0.21–0.41%, respectively, and showed 99–100% uniformity in drug content. The coated tablets exploiting different polymer combinations were evaluated for drug release under different pH conditions. The formulation containing Eudragit-S^®, Eudragit-L^® and cellulose acetate phthalate (ES^®, EL^® and CAP) (1:1:1) displayed desired release pattern with only 9.75% drug release in first 5 h (lag phase) and satisfactory release in lowered pH conditions. Drug release increased with the plasticizer (triacetin) concentration. Increase in the concentration of inulin and citric acid above 5% w/w increases the drug release. The addition of inulin in the formulation with coating level 28% w/w demonstrated increased drug release in presence of rat cecal content. Thus inulin containing ES^®, EL^® and CAP (1:1:1) polymer-coated formulation system can be used for the targeted delivery of azathioprine with desired release pattern.

Keywords::

• Colon-targeted drug delivery
• polysaccharide
• azathioprine
• Eudragit-S^®
• Eudragit-L^®
• cellulose acetate phthalate
• rat cecal content

Acknowledgements

The Authors are thankful to Vapi Care Private Ltd, Glenmark Pharmaceuticals and Signet Chemical Corporation, India for their generous gifts of the materials.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.