In the present investigation enteric coated formulation of proton pump inhibitor which is a substituted benzimidazole derivative was developed to enhance its stability. The tablets were coated with HPMC phthalate based enteric polymer with different amount of plasticizers and talc. Prior to enteric coating core tablets were seal coated to prevent interaction between core and enteric layer. The core tablets were separated into three groups and seal coated with a colour coding scheme to coverage levels of 2% (white colour), 2.5% (yellow colour), 3% (orange colour) weight gains. The purpose of colour coding was to carry out the coating simultaneously to reduce the number of experiments and eliminate potential differences that may exist during separate coating processes. The tablets were coated with three HPMC phthalate based enteric formulations containing different amounts of plasticizer and talc. During each enteric coating process, a predetermined amount of labeled tablets were removed after attaining 6, 8, and 10% weight gains. Dissolution results revealed that all enteric coated formulations inhibited drug release for 2 h in 0.1 N HCl and drug release at most intermediate sampling time points in phosphate buffer, pH 6.8.