Formulation and optimization of gastric floating drug delivery system using Central composite design and its biopharmaceutical evaluation

The present work investigates the formulation and biopharmaceutical estimation of gastric floating drug delivery system [GFDDS] of propranolol HC1 using semi-synthetic polymer carboxymethyl ethyl cellulose [CMEC] and a synthetic polymer polyethylene oxide [PEO]. A central composite design was applied for optimization of polymer quantity [CMEC or PEO and sodium bicarbonate concentration as independent variables. The dependent variables evaluated were:% of drug release at 1 hr [D[1hr]],% drug release at 3 hr [D[3hr]] and time taken for 95% of drug release [t[95]]. Numerical optimization and graphical optimization were conducted to optimize the response variables. All observed responses of statistically optimized formulations were in high treaty with predicted values. Accelerated stability studies were conducted on the optimized formulations at 40 +/- 2[degree]C/75% +/- 5% RH and confirm that formulations were stable. Optimized formulations were evaluated for in vivo buoyancy characterization in human volunteers and were found buoyant in gastric fluid. Gastric residence time was enhanced in the fed but not the fasted state. The optimized formulations and marketed formulation were administered to healthy human volunteers and evaluated for pharmacokinetic parameters. Mean residence time [MRT] was prolonged and AUC levels were increased for both optimized floating tablets when compared with marketed product. High relative bioavailability obtained with optimized gastric floating tablets compared to commercial formulation, indicated the improvement of bioavailability

Bioactive molecules: current trends in discovery, synthesis, delivery and testing

Important bioactive molecules are molecules that are pharmacologically active derived from natural sources and through chemical synthesis. Over the years many of such molecules have been discovered through bioprospective endeavours. The discovery of taxol from the pacific yew tree bark that has the ability in stabilising cellular microtubules represents one of the hallmarks of success of such endeavours. In recent years, the discovery process has been aided by the rapid development of techniques and technologies in chemistry and biotechnology. The progress in advanced genetics and computational biology has also transformed the way hypotheses are formulated as well as the strategies for drug discovery. Of equal importance is the use of advanced drug delivery vehicles in enhancing the efficacy and bioavailability of bioactive molecules. The availability of suitable animal models for testing and validation is yet another major determinant in increasing the prospect for clinical trials of bioactive molecules.