Investigation and Optimization of the Effect of Polymers on Drug Release of Norfloxacin from Floating Tablets.

BACKGROUND: Norfloxacin is fluoroquinolone anti-infective used in the treatment of urinary tract infections, prostatitis, gonorrhea and genital tract infections. It has plasma half life of 3 to 4 h requiring multiple dosing in the treatment. Releaseretarding polymers can be used to modulate the drug release of norfloxacin. OBJECTIVES: The objective of this study was to investigate the effect of release-retarding polymers on the drug release of norfloxacin from floating tablets. MATERIAL AND METHODS: Norfloxacin was procured as a gift sample from Concept Pharma Ltd. Aurangabad (India) and HPMC K100M was procured as a gift sample from Colorcon Asia Pvt. Ltd., Goa (India). The tablets were prepared by direct compression method and various pharmaceutical parameters were evaluated. RESULTS: It was observed that all tablet formulations F1-F9 retained the drug release up to 12 h with good floating property but only Batch-F4 complies with the USP dissolution limits with a minimum floating lag time. The drug release kinetics were evaluated by the model-dependent (curve fitting) method using PCP Disso v3 software shows Batch-F4 shows to best fit with Peppas model for which R2 value was 0.9921 and the release exponent value was 0.6892. CONCLUSIONS: The drug release kinetics study indicates that the floating tablets release the drug by diffusion followed by erosion mechanism. Obtained in-vitro drug release data was analyzed by design expert software for drug release at first hour and at 12th h values and found that release the selected independent variables like HPMC K100M and sodium alginate concentration has a significant effect on drug release.

Design and development of controlled porosity osmotic tablet of diltiazem hydrochloride.

The present work aims towards the design and development of extended release formulation of freely water-soluble drug diltiazem hydrochloride (DLTZ) based on osmotic technology by using controlled porosity approach. DLTZ is an ideal candidate for a zero-order drug delivery system because it is freely water-soluble and has a short half-life (2-3 h). Sodium chloride (Osmogen) was added to the core tablet to alter the solubility of DLTZ in an aqueous medium. Cellulose acetate (CA) and sorbitol were used as semipermeable membrane and pore former, respectively. The effect of different formulation variables namely concentration of osmogen in the core tablet, % pore former, % weight gain, pH of the dissolution medium and agitation intensity on the in vitro release was studied. DLTZ release was directly proportional to % pore former and inversely proportional to % weight gain. The optimized formulation (F8) delivered DLTZ independent of pH and agitation intensity for 12 h at the upper level concentration of % pore former (25% w/w) and middle level concentration of % weight gain (6% w/w). The comparative study of elementary osmotic pump (EOP) and controlled porosity osmotic pump revealed that it superior than conventional EOP and also easier and cost effective to formulate.