Formulation and evaluation of mucoadhesive chitosan microspheres of carvedilol for nasal administration

Abstract

The aim of this study was to develop and characterize chitosan microspheres of Carvedilol (CRV) for nasal delivery to improve bioavailability for treatment of hypertension and angina pectoris. Carvedilol comes under BCS class II, is poorly water soluble drug and highly permeable. Solubility of drug is determined by shaking flask method and lipophilicity of drug is determined by separating funnel method. The nasal route is very convenient for achieving high bioavailability and reduce hepatic first pass metabolism. Chitosan is obtained from chitin of fish, is biodegradable and nontoxic that is suitable for nasal administration. The microspheres were prepared by cross- linking method using glutaraldehyde as cross linking agent and this preparation is evaluated for size, entrapment efficiency (EE), in vitro mucoadhesion, in vitro drug release. The mucoadhesive property was also evaluated by in vitro wash off test. The microspheres were spherical with size of 15-40 micron, which is favorable for intranasal absorption. The EE was observed from 40% to 88% while percentage of mucoadhesion was from 74%to 88%. A strong interaction between mucin and chitosan microspheres was detected explaining absorption with electrostatic interaction. The microspheres released around 80% of drug in 6h. It was concluded that chitosan microspheres could be used to deliver CRV following nasal administration for improving the bioavailability.