Formulation and Evaluation of Floating Gastroretentive Drug Delivery System of Diltiazem Hydrochloride

The present investigation describes the design and evaluation of monolithic gastro retentive dosage forms of diltiazem. Hydrophilic cellulose derivatives, Sodium alginate, Sodium carboxy methyl cellulose, Polyox, Methocel K100M in combination with Methocel E6LV are used as the rate controlling polymers. Sodium bicarbonate was incorporated as gas generating agent. Tablets were prepared by employing a wet granulation process and evaluated for the different evaluation parameters such as thickness, diameter, drug content uniformity, friability, floating lag time, in-vitro buoyancy, in-vitro drug release studies and stability studies were performed. All the evaluation parameters results were significant. DSC studies indicated absence of interaction between the drug and excipients. The release rate, extent and mechanisms were found to be governed by polymer and floating agent content. Kinetics of drug release from tablet followed Higuchi and Korsmeyer equations. Both Formula F-5 & F-6 were stored at 40°C/75% RH for 3 months according to ICH guidelines. From all the formulations F6 was found to be optimized formulation based on the results obtained from the studies. Abdominal X-ray imaging of formula F-6, loaded with barium sulfate, in eight healthy human volunteers revealed a mean gastric retention period of 5.50 ± 0.55 h. It is concluded that the gastro retentive tablet of diltiazem HCl can be prepared via floating mechanism to increase its residence time and thereby increasing its availability for absorption from the stomach or upper gastrointestinal tract (GIT).