buoyancy

The aim of the current study was to formulate and characterize oral floating alginate microspheres of Rebamipide to sustain the gastric residence time and to target gastritis. The floating alginate microspheres were prepared by ionotropic gelation technique. Sodium alginate was used as polymer, sodium bicarbonate as gas generating agent, calcium chloride as cross-linking agent, HPMC K4, HPMC K15 as rate retarding agent. Microspheres were characterized for the Micromeretic properties, entrapment efficiency, buoyancy test, SEM analysis, FTIR, and in vitro release studies. The release studies were carried out in 0.1N HCl and the results were applied to various kinetic models.  Among the total 14 formulations F12 was optimized. The % yield of F12 formulation was found to be 93.73%. On the basis of optical microscopy, the particle size was 79.45±0.09µm. The % buoyancy, % entrapment efficiency and swelling index of F12 formulation was 94.2%, 95.5% and 96.16, respectively. The Cumulative % drug release of F12 formulation was 96.12±0.22% in 12h when compared with marketed product 95.15±0.23 in 1h.  SEM studies showed the particles were in spherical shape. Based on obtained results, floating alginate microspheres were of good candidate for targeting to GIT in the efficient management of gastritis.

The purpose of the research was to prepare and evaluate Roxatidine acetate HCl floating microspheres by ionotropic gelation method. Fourteen formulations were prepared, among all the formulations F13 was selected as optimized formulation based on the micromeretic and evaluation parameters including drug release studies. In the in vitro release study of formulation, F13 showed 95.65% drug release after 12 h in a controlled manner, which is desired for disease like peptic ulcer. In vitro release profiles from optimized formulation F13 were applied on various kinetic models. The best fit with the highest correlation coefficient was observed in zero order and Higuchi model, indicating diffusion controlled principle. The innovator Rotane 150 mg conventional tablet showed the drug release of 96.45% within 1 h. FT-IR and DSC analyses confirmed the absence of drug-polymer interaction. The results obtained from evaluation and performance study of different types of Roxatidine microspheres showed that system may be useful to achieve a controlled drug release profile, reduce the dose of drug, dosing frequency and improve patient compliance when compared with marketed product. Key words: Roxatidine, buoyancy, HPMC, gum olibanum, microspheres.

Atorvastatin Tablet is one of the best selling drugs in the world, but still it suffers inadequate bioavailability problem from oral dosage. An attempt was taken to evaluate the floating drug delivery system for Atorvastatin by incorporating it in different grades of Carbomer matrix. Direct compression technique was selected and different once daily formulations were designed. The tablets were successfully floated over prolonged time and released the drug at a controlled fashion depending on the grade and quantity of Carbomer used. The tablets were evaluated for different physical tests including weight variation, friability, hardness, diameter and thickness. The compatibility between drug and polymers were confirmed by FT-IR spectra. Buoyancy characteristics of the tablets were determined by observing lag time, swelling index and total buoyancy period. The mechanism of drug release from the matrixes was assumed by fitting the release profile with different mathematical equations. Formulation F-5 and F-10 were found to release the drug at most sustaining manner and also had the longest total floating time. 

The present work is aimed at formulation and evaluation of floating drug delivery system of nateglinide for the management of diabetes. Hollow microspheres (microballoons), loaded with nateglinide in their outer polymer shells were prepared by using emulsion solvent diffusion method. The prepared formulations were evaluated for their surface morphology by scanning electron microscopy (SEM), micromeretic properties, % drug entrapment efficiency, % buoyancy and in-vitro drug release studies. The prepared microspheres exhibited prolonged drug release (24 h) and remained buoyant for >12 h. The mean particle size increased and the drug release rate decreased at higher polymer concentrations. No significant effect of the stirring rate during preparation on drug release was observed. The release pattern of nateglinide in simulated gastric fluid from all floating microspheres showed their sustained action.