Development and in vitro evaluation of mucoadhesive microsphere carriers for intranasal delivery of betahistine dihydrochloride

The aim of the present work was to formulate and evaluate betahistine-loaded chitosan microspheres intended for nasal delivery with focus on their mucoadhesive properties. Betahistine-loaded chitosan microspheres were obtained via W/O emulsion solvent evaporation technique and were characterized for particle size, surphace morfology and entrapment efficiency. FTIR spectroscopy was carried out to evaluate drug-polymer interaction and powder X-ray diffractometry was applied to investigate crystallinity transformations. Tensile studies were carried out using sheep nasal mucosa to evaluate in vitro mucoadhesion. Drug release into phosphate buffer saline pH 7.4 was performed and dissolution profiles of the formulations were obtained. The results showed that the microspheres were spherical in shape having smooth surface and mean particle size of 3.82 øm to 7.69 øm which is appropriate for optimum deposition in the nasal cavity. The mean particle size increased when chitosan solutions with higher viscosity were used. In vitro mucoadhesion studies indicated that chitosan microspheres had good mucoadhesive properties and could adequately adhere to nasal mucosa. It was observed that polymer concentration enhancement led to increased mucoadhesive strength. Betahistine release studies from the microspheres showed similar and slightly icreasing dissolution profiles. Acording to the obtained results, betahistine-loaded chitosan microspheres prepared by solvent evaporation method proved to be capable of sustained release and could be used via nasal route as an alternative to oral administration.