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.
Among oral dosage form, liquid dosage forms are more prone to low bioavailability because of their quick transit from the gastrointestinal tract. Sustained release liquid formulation with efficacy can be produced using approach of In situ gel. The purpose of the present work was to develop oral in situ gelling system using Gellan gum for in situ gelation of ambroxol-HCl. The formulation variables like concentration of polymer and calcium chloride will be optimized using factorial design. Optimized formulations were prepared having desirability and evaluated for various parameter.
Alginate based floating in situ gelling systems of famotidine (FIGF) were prepared by dissolving varying concentrations of alginate in deionized water containing sodium citrate, to which varying concentrations of drug and calcium chloride was added and dissolved by stirring. Results of preliminary trials indicate that concentrations of sodium alginate, calcium chloride and sodium citrate affected the characteristics of in situ gel. A 32 full factorial design was employed to study the effect of independent variables, concentration of sodium alginate (X1) and concentration of calcium chloride (X2) on dependent variables, i.e. viscosity, drug content, drug release at 4 hrs (Q50) and drug release at 8 hrs (Q80). A sustained drug release was obtained for more than 8 hrs. In vivo testing of FIGF to albino Wistar rats demonstrated significant anti-ulcer effect of famotidine.
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