Preparation and characterization of HSA-propranolol microspheres for nasal administration

Abstract

Human serum albumin based microspheres bearing propranolol hydrochloride were prepared by an emulsion internal phase stabilization technique. The prepared microspheres were tested for release characteristics, bioadhesion and controlled in vivo absorption following nasal administration. The factors, which include HSA concentration and stabilization temperature in the case of heat stabilized microspheres and density, were studied for their effect on release characteristics and bioadhesion. The albumin microspheres were noted to possess good bioadhesion, and to release the contents slowly. However, the release rate was related to the period of heat treatment given for stabilization which in turn was related to the density of microspheres. In vivo experiments revealed that the nasal administration of an albumin based system eliminated first pass metabolism and could maintain an effective drug concentration for 10–12 h with improved bioavailability as compared to that following intravenous drug administration. Moreover, magnetite containing microspheres on application of an external magnetic field of 8 kOe strength exhibited additional pulse dosing at the magnet application point. This latter effect could be exploited for drug plasma level monitoring.