Abstract. A novel gastro retentive controlled release drug delivery system of verapamil HCl was formulated in an effort to increase the gastric retention time of the dosage form and to control drug release. Hydroxypropylmethylcellulose (HPMC), carbopol, and xanthan gum were incorporated for gelforming properties. Buoyancy was achieved by adding an effervescent mixture of sodium bicarbonate and anhydrous citric acid. In vitro drug release studies were performed, and drug release kinetics was evaluated using the linear regression method. The optimized intragastric floating tablet composed of 3:2 of HPMC K4M to xanthan gum exhibited 95.39% drug release in 24 h in vitro, while the buoyancy lag time was 36.2 s, and the intragastric floating tablet remained buoyant for >24 h. Zero-order and nonFickian release transport was confirmed as the drug release mechanism from the optimized formulation (F7). X-ray studies showed that total buoyancy time was able to delay the gastric emptying of verapamil HCl intragastric floating tablet in mongrel dogs for more than 4 h. Optimized intragastric floating tablet showed no significant change in physical appearance, drug content, total buoyancy time, or in vitro dissolution pattern after storage at 40°C/75% relative humidity for 3 months.

In this study famotidine was used as a model drug to formulate and evaluate pH-induced in situ gelling system for oral sustained release drug delivery in stomach which has shorter biological half-life. To study the effect of independent variables 32 full factorial design was employed, concentration of pectin as pH dependant polymer and concentration of calcium chloride on dependent variables like viscosity, drug content, 50% and 80% drug release and similarity factor. It was found that both the concentration of pectin and concentration of calcium chloride had significant effect on viscosity, drug content, 50% and 80% drug release and similarity factor of the system. In vitro drug release study showed that drug released from the in situ gel followed non-Fickian diffusion. Mathematical modeling was employed for quantitative evaluation of the effect of formulation variables. Rat pylorus legation model was used for in vivo study of the selected formulation. Results shows gel formation in gastric juice and reduction in ulcer index. There were few or no major changes in the formulation during three months stability testing. The in situ gelling systems are useful for delivery of famotidine.

The Oral drug delivery remains the preferred route for administration of various drugs. Recent developments in the technology have prompted scientists to develop fast disintegrating tablets (FDTs) with improved patient compliance and convenience. This tablet format is designed to allow administration of an oral solid dose form in the absence of water or fluid intake. Such tablets readily dissolve or disintegrate in the saliva generally within <60 seconds. Fast-or mouth dissolving tablets have been formulated for pediatric, geriatric, and bedridden patients and for active patients who are busy and traveling and may not have access to water. Such formulations provide an opportunity for product line extension in the Many elderly persons will have difficulties in taking conventional oral dosage forms (viz., solutions, suspensions, tablets, and capsules) because of hand tremors and dysphagia. Swallowing problems also are common in young individuals because of their underdeveloped muscular and nervous systems. FDTs are solid unit dosage forms, which disintegrate or dissolve rapidly in the mouth without chewing and water. Orally disintegrating tablets provide an advantage particularly for pediatric and geriatric populations who have difficulty in swallowing conventional tablets and capsules. This review describes the various formulation aspects, disintegrants employed and technologies developed for FDTs, along with various excipients, evaluation tests, marketed formulations, and drugs explored in this field.