Mettu Srikanth Reddy

The purpose of writing this review on floating drug delivery systems (FDDS) was to compile the recent literature with special focus on the principal mechanism of floatation to achieve gastric retention. The aim of writing this review on gastro retentive and floating drug delivery system was to compile the new literature with the principle mechanism of floatation to acquired gastric retention. The methodologies used in the development of FDDS by formulating effervescent and non effervescent floating tablets based on buoyancy mechanism. FDDS are of particular interest for drugs that are locally active and have narrow absorption window in stomach or upper small intestine, unstable in the intestinal or colonic environment, and exhibit low solubility at high pH values. This review article is in pursuit of giving detailed information on the pharmaceutical basis of their design, classification, advantages, in vitro evaluation parameters. Controlled release (CR) dosage forms have been extensively used to improve therapy with several important drugs. The recent developments of floating drug delivery systems (FDDS) including the physiological and formulation variables affecting gastric retention, approaches to design single-unit and multiple-unit floating systems, and their classification and formulation aspects are covered in detail. This review also summarizes the in vitro techniques, in vivo studies to evaluate the performance and application of floating systems. Floating dosage form can be prepared as tablets, capsules by adding suitable ingredients as well as by adding gas generating agent. In this review various techniques used in floating dosage forms along with current & recent developments of stomach specific floating drug delivery system for gastro retention are discussed.

Nebivolol Hydrochloride is a third generation beta blocker used for the treatment of hypertention and heart failure. Nebivolol is rapidly absorbed following oral administration, reaching peak plasma concentrations in 0.5 – 4.0 hrs. The present study was designed to develop a suitable matrix type transdermal drug delivery system (TDDS) for Nebivolol Hydrochloride employing various ratios of hydrophilic and hydrophobic polymers by solvent casting technique. The developed patches were then evaluated for physicochemical characterization, ex-vivo permeation and skin irritation studies. The compatibility of drug with other ingredients was checked by FTIR studies. FTIR results revealed that there was no interaction between dug and other excipients. The transdermal patches obtained were transparent, smooth, uniform and flexible. The results of physicochemical properties were within the pharmacopoeial limits. All the formulations were subjected to ex-vivo skin permeation study by means of Franz’s diffusion cell in order to optimize the suitable formulation. Two formulations with the polymeric blend 3:2 (HPMC E50: ERL 100 and HPMC E15: ERL100 respectively) showed an increase in permeation of drug via skin when compared with the formulations having less proportion of hydrophilic polymer (HPMC), however the formulation with HPMC E50 : ERL 100 showed overall improvement in flux and permeation, hence it was optimized as suitable matrix system. The drug release follows zero order kinetics with diffusion mechanism. The average steady state flux obtained with HPMC E50: ERL 100 (3:2) was 43.3 µg/cm2/hr and the same was increased to 59.2 µg/cm2/hr with the incorporation of 5% v/w of DMSO as permeation enhancer. In conclusion, the present data confirm the feasibility of developing Nebivolol Hydrochloride transdermal system. The release rate of drug through patches increased when the concentration of hydrophilic polymer was increased.