FORMULATION AND DEVELOPMENT OF ENTERIC COATED ORNIDAZOLE TABLET FOR COLON TARGETED DRUG DELIVERY SYSTEM

Abstract

Lactose-based placebo tablets were prepared and coated using various combinations of Eudragit L100 and Eudragit S100, by spraying from aqueous systems. The Eudragit L100 Eudragit S100 combinations (w/w) studied were 1:0, 4:1, 3:2, 1:1, 2:3, 1:4, 1:5 and 0:1. The coated tablets were tested in vitro for their suitability for pH dependent colon targeted oral drug delivery. The same coating formulations were then applied on tablets containing ornidazole as a model drug and evaluated for in vitro dissolution rates under various conditions. The disintegration data obtained from the placebo tablets demonstrate that disintegration rate of the studied tablets is dependent on: (i) the polymers combination used to coat the tablets, (ii) pH of the disintegration media, and (iii) the coating level of the tablets. Dissolution studies performed on the ornidazole tablets further confirmed that the release profiles of the drug could be manipulated by changing the Eudragit L100 and Eudragit S100 ratios within the pH range of 6.0 to 7.0 in which the individual polymers are soluble respectively, and a coating formulation consisting of a combination of the two copolymers can overcome the issue of high gastrointestinal (GI) pH variability among individuals. The results also demonstrated that a combination of Eudragit L100 and Eudragit S100 can be successfully used from aqueous system to coat tablets for colon targeted delivery of drugs. For colon targeted delivery of drugs the proposed combination system is superior to tablets coated with either Eudragit L100 or Eudragit S100 alone.

Keywords: Aqueous film coating; Colon targeted drug delivery; Enteric coated tablet; Ornidazole; pH-dependent delivery system.