www.ijpsonline.com Research Research Research Research Research Paper Paper Paper Paper Paper In Vitro In Vitro In Vitro In Vitro In Vitro Dissolution Kinetic Study of Theophylline Dissolution Kinetic Study of Theophylline Dissolution Kinetic Study of Theophylline Dissolution Kinetic Study of Theophylline Dissolution Kinetic Study of Theophylline from Mixed Controlled Release Matrix T from Mixed Controlled Release Matrix T from Mixed Controlled Release Matrix T from Mixed Controlled Release Matrix T from Mixed Controlled Release Matrix Tablets ablets ablets ablets ablets Containing Hydroxypropylmethyl Cellulose and Containing Hydroxypropylmethyl Cellulose and Containing Hydroxypropylmethyl Cellulose and Containing Hydroxypropylmethyl Cellulose and Containing Hydroxypropylmethyl Cellulose and Glycerylbehenate Glycerylbehenate Glycerylbehenate Glycerylbehenate Glycerylbehenate H. K. RASLAN AND H. MASWADEH* Department of Pharmaceutical Technology, School of Pharmacy, Al-Isra University, P. O. Box 182835, Code No. 11118 Amman, Jordan. Oral dosage forms containing 300 mg theophylline in matrix-type tablets were prepared by direct compression method using two kinds of matrices – glycerylbehenate (hydrophobic) and hydroxypropylmethyl cellulose (hydrophilic). T he in vitro release kinetics of these formulations were studied at pH 6.8 using the USP dissolution apparatus with the paddle assemble. T he kinetics of the dissolution process were studied by analyzing the dissolution data using four kinetic equations – the zero-order equation, the first-order equation, the Higuchi square root equation, and the H ixson-Crowell cube root law. T he analysis of the dissolution kinetic data for the theophylline preparations in this study shows that it follows the first-order kinetics, and the release process involves erosion/ diffusion and an alteration in the surface area and diameter of the matrix system as well as in the diffusion path length from the matrix drug load during the dissolution process. T his relation is best described by the use of both the first-order equation and Hixson-Crowell cube root law. A number of methods and techniques have been used in attacks. Due to its low therapeutic index, careful control the manufacturing of oral extended-release dosage forms. of its release from dosage forms has to be ensured. Probably the simplest and least expensive way to control Faulty formulation may result in the release of large the release of an active agent is to disperse it in an inert amounts of theophylline, i.e., dose dumping, and hence polymeric matrix 1 . In polymeric system, the active agent is could produce toxic effects 9 . physically blended with the polymer powder and then fused together by compression moulding, which is a The aim of the present work was to study the utility of common process in the pharmaceutical industry 2-4 . These using glycerylbehenate and hydroxypropylmethyl cellulose dosage forms are designed to deliver the drug at a for the formulation of a controlled-release anhydrous controlled and predetermined rate, thus maintaining a theophylline matrix tablets and to study the in vitro release therapeutically effective concentration of the drug in the characteristics and kinetics of the prepared formulations. systemic circulation for a long period of time and The kinetics of the dissolution process were studied by therefore reducing the frequency of dosing and the application of four kinetic equations to the dissolution improving patient compliance 5,6 . Hydrophobic material data–namely, the zero-order, the first-order, the such as glycerylbehenate for an insoluble matrix carrier, Highuchi-square root and Hixson-Crowell cube root law and a water-soluble hydrophilic material such as equations. hydroxypropylmethyl cellulose have been reported as the most commonly used matrix carriers 7,8 . MATERIALS AND METHODS Anhydrous theophylline, a xanthine bronchodilator, is Hydroxypropylmethyl cellulose (Methocel K15 M) was used in the treatment of both chronic and acute asthmatic obtained from Dow Chemical, Midland, Michigan, USA.; glycerylbehenate (Compritol 888 ATO) from Gattefosse, *For correspondence Paramus, NJ, USA.; anhydrous theophylline from Sigma E-mail: maswadehhamza@hotmail.com Chemical Co., St. Louis, USA.; microcrystalline cellulose Indian Journal of Pharmaceutical Sciences May - June 2006 308