Recent advances in gastric floating drug delivery technology: a review.

Gastric floating drug delivery systems have been an avenue of considerable interest in terms of their immense potential for better pharmacotherapeutic interventions along with site-specific absorption. These buoyant systems significantly enhance the bioavailability and controlled delivery of several drug molecules. Scientific investigators have also carried out substantial research endeavours worldwide in order to design a more systematic and intellectual floating systems. The present manuscript is an attempt to highlight numerous recent advancements in the design of gastric floating drug delivery systems along with various available commercial preparations. Salient applications, characterization aspects and future perspectives of these multifarious systems have also been addressed.

Design and development of nevirapine loaded surfactant free chitosan microemulsion.

Emulsification of liquid paraffin oil in aqueous solutions of chitosan without adding any additional surfactant is studied. The main objective of this study was to evaluate the dispersion of castor oil in aqueous phase in the presence of chitosan, and how this polymer promotes the stability of the obtained emulsions. Nevertheless, chitosan promotes emulsion production by increasing the matrix viscosity and provides stabilization of the oil-water interface by forming a dense hydrophilic polyelectrolytic brush on the water side of interface, which presents a significant barrier for coalescence--both steric and electrostatic. Chitosan stabilizes the emulsion mainly by the steric effect. These steric effects generate Van der Waals repulsion forces when two particles are too close. After loading with antiviral drug nevirapine, these emulsions were characterized in terms of phase contrast microscopy, hot stage microscopy, fluorescence microscopy, particle size, zeta potential, viscosity, entrapment efficiency and release studies using dialysis bag method. The prepared emulsions were stable in terms of mean globule size, change in drug content and retain they cationicity. The formulated emulsions are a promising carrier for nevirapine and other lipophilic drugs.