The effect of the hydrophilic polymers such as sodium carboxymethyl cellulose, (NaCMC) and the hydrophobic polymers such\nas Eudragit RL100 and Eudragit RS 100 on the dissolution and the release rate of drug when prepared as controlled release\nmatrices were studied. Tablets were prepared by a direct compression technique. The dissolution tests were performed by both\nthe basket and the paddle methods. In the present study the acrylic resins Eudragit RS 100 and Eudragit RL 100 are separately\nmixed with the anionic and hydrophilic polymer NaCMC and the other excipients in an attempt to prepare controlled release\nmatrices and to investigate the effect of the charge and composition of these polymers on the drug release. Also the research\nwill study the effect of the pH of the dissolution medium, and the storage of the matrices at different temperatures, on the\nrelease rate of the drug. It was found that percent, charge of the polymers, pH of the dissolution medium and storage of\nmatrices at different temperatures affect the release rate of the drug. The experiments were performed in vitro and the data\nobtained were plotted according to four kinetic models to study the release kinetic. These models were zero order release, first\norder release, Higuchi equation, and Korsmeyer equation. Zero order release was observed in the formulation with a high\npercent of the hydrophilic polymers, while high percent of hydrophobic polymers didn�t show zero order release and the drug\nwas liberated in a less time from the matrices.
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