Development of enteric-coated pectin-based matrix tablets for colonic delivery of theophylline

Journal of Drug Targeting, 2003 Vol. 11 (6), pp. 365–371

Development of Enteric-coated Pectin-based Matrix Tablets for Colonic Delivery of Theophylline
´ ´ PAOLA MURAa,*, FRANCESCA MAESTRELLIa, MARZIA CIRRIa, M. LUISA GONZALEZ RODRIGUEZb and ANTONIO M. RABASCO ALVAREZb a ` Universita degli Studi di Firenze, Dipartimento di Scienze Farmaceutiche, via Gino Capponi 9, 50121 Firenze, Italy; ` ´ ´ ´ ˜ Departamento de Farmacia y Tecnologıa Farmaceutica, Universidad de Sevilla, C/ Prof. Garcıa Gonzalez, s/n. 41012 Sevilla. Espana

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(Received 7 July 2003)

The present work was aimed at developing a new colonic drug delivery system which takes advantage of the combined approaches of a specifically colon-biodegradable pectin matrix with a pH-sensitive Eudragitw S100 polymeric coating. The developed system was able to suitably retard the onset of drug release and to provide a colon-specific delivery, thus overcoming the problems of pectin solubility in the upper gastrointestinal tract and low site-specificity of simple pH-dependent systems. Due to the poor compactability properties of pectin, it was used in mixture with Emdexw, a hydrophilic directlycompressible material, in order to make it possible to prepare tablets by direct compression. Theophylline (TP) was used as model drug due to its suitable pharmacokinetic properties for colonic delivery and good absorption in the large intestine. The effects of varying the type of pectin (low and high methoxylated, or amidated), the pectin:Emdexw ratio and the level of the pH-dependent polymeric coating on drug release behavior were investigated. Release tests were performed using sequential liquids simulating the physiological variation of pH and the effect of the presence or not of pectinolytic enzymes into the simulated colonic medium was evaluated. Thirty percent (w/w) was the the minimum