Ramana G

The objective of present investigation was to prepare a chrono-modulated drug delivery system for Naproxen sodium to meet chrono pharmacological needs of Arthritis. Press coated tablets is a novel oral pulsatile release drug delivery system in which  the drug is released after certain period of lag time generally due to the erosion of barrier layers. Tablets were prepared by direct compression method. The core tablet was formulated using super-disintegrants like sodium starch glycolate, crosspovidone and crosscarmellose sodium. Whereas, the barrier layer contains polymers like carrageenan gum (Viscarin GP-209), xanthan gum in different concentrations and lactose anhydrous as channeling agent for maintaining lag time. The drug-excipient compatibility was confirmed by using FTIR, predicted that there was no chemical interactions between the drug and excipients. The tablets prepared were evaluated for micromeritic properties. In-vitro drug release studies were carried out using pH 1.2 buffer for initial 2hrs and in pH 7.4 phosphate buffer for remaining 10hrs. All the formulations followed first order release kinetics. From the obtained results it was found that the F9 formulation of immediate release core tablets (10% of Crosspovidone) showed optimized in vitro disintegration time and wetting time respectively. In case of press-coated tablets PCT 8 formulation with hydrophilic polymers 19.2% carrageenan gum, 19.2% xanthan gum and 7.69% lactose anhydrous as channeling agent has shown 6hrs of lag time is considered as optimum formulation and is successful in resisting different RPM pressures for designing into pulsatile delivery for treatment of Arthritis.

The objective of the present work was to formulate and characterize a Gastro retentive drug delivery system (GRDDS) for Clopidogrel Bisulphate to improve bioavailability and to minimize the side effects such as gastric bleeding and drug resistance development. Clopidogrel floating tablets were prepared by direct compression technique by using HPMC K-100M(Hydroxy Propyl Methyl Cellulose), PEO(polyethylene oxide POLYOX WSR 303) and Carbopol 971P as release retarding agents in different concentrations. Sodium bicarbonate and microcrystalline cellulose (MCC) were used as gas generating agent and diluents respectively. Studies were carried out on floating behavior and influence of polymer type on drug release rate. All the formulations were subjected to various quality control and in-vitro dissolution studies. All the formulations followed first order kinetics, Higuchi drug release kinetics with diffusion as the dominant mechanism of drug release. As per Korsmeyer-Peppas equation, the release exponent “n” ranged 0.381-0.561 indicating that drug release from all the formulations was by non-Fickian diffusion mechanism. The release rate of Clopidogrel was found to be affected by the type and concentration of the polymer used in the formulation. As the concentration of the polymer was increased, the drug release was found to be retarded. Based on the results, Clopidogrel floating matrix tablets prepared by employing HPMCK100M at concentration 35% w/w (F9) was the best formulation with desired in-vitro floating time and dissolution. The FT-IR and DSC studies revealed that there was no interaction between drug and excipients.