§16§The objective of present work was to check the effect of hydrophilic polymers on the release of Clozapine from matrix tablet. Hydrophilic polymers were used to control the release of drug. Matrix tablets were prepared using direct compression method. HPMC K 100 M, Guar gum and Sodium CMC used as release retardant polymers. Polymers were used in the ratio of 1:3, 1:4, 1:5 and 1:8. Rate of drug release decreased as the polymer ratio increased. The level of polymer ratio also had an effect on swelling index showing a linear relationship. At 1:8 (drug: polymer) ratio with HPMC K 100 M, tablets showed desirable release pattern, release up to 24 hr. It was found to release the drug in Zero order up to 24 hrs. For further study, 1:8 (drug: polymer) ratio was evaluated with particle sizes ranging from 250 micron to 106 microns on the release of drug. It was observed that as the particle size decreases, release also retards but follows zero order kinetics.
