Design and evaluation of colon targeted modified pulsincap delivery of 5-fluorouracil according to circadian rhythm

INTRODUCTION: A modified pulsincap dosage form of 5-fluorouracil was developed to target drug to colorectal carcinoma according to daily oscillations of rate-limiting metabolizing enzyme dihydropyrimidine dehydrogenase. MATERIALS AND METHODS: The capsule body was made water insoluble by exposing the body to formaldehyde vapor. A mixture of granules containing drug, superdisintegrant, and osmogen was filled in the capsule body. A hydrogel plug was fitted to the mouth of the treated body, and the untreated cap was fitted to the body which was coated with Eudragit S100. Developed formulations were evaluated for in vitro drug release in 1.2 pH (2 h), 6.8 pH (3 h), and 7.4 pH (up to 12 h) buffer solutions. A 2(3) full factorial design was used for optimization in which the type of hydrogel plug (X1), the type of osmogen (X(2)), and the type of superdisintegrant (X(3)) were selected as independent variables while, cap opening time, percentage drug released in 5(Q(5)), 6(Q(6)), and 12(Q(12)) h were taken as dependent variables. RESULTS: Dissolution data were fitted to various models to ascertain the kinetic of drug release. Regression analysis and analysis of variance were performed for dependent variables. The results of the F-statistics were used to select the most appropriate model. CONCLUSION: Formulation F(1) containing sodium starch glycolate, potassium chloride, and hydroxypropyl methylcellulose K4M plug was considered optimum since it showed more similarity to the theoretical predicted dissolution profile (f(2) = 77.33). The studies indicate that the formulation was effective in providing in vitro colon targeted release and controlled release after predetermined lag time.