Preparation and in Vitro Characterization of Mucoadhesive Progesterone -egg Albumin Microspheres for Nasal Administration

In the undertaken study cross linked egg albumin microspheres of progesterone (PG) have been investigated through the nasal route. A smooth, spherical, cross-linked egg albumin microsphere in the size range of 15-37 μm loaded with progesterone were prepared by multiple emulsion (o/w/o) method by glutarldehyde cross-linking and thermal denaturation techniques. Microspheres were prepared by using different drug/polymer ratios. Egg albumin was used as a mucoadhesive polymer in the formulation to increase the residence time of the microspheres on the nasal mucosa. The albumin microspheres were characterized and evaluated with respect to the particle size, production yield, encapsulation efficiency, shape and surface properties, drug polymer interaction, mucoadhesive property and suitability for nasal drug delivery. The effect of process variables on particle size of microspheres was also studied. Shape and surface morphology were examined using scanning electron microscopy. Placebo microspheres exhibited the smooth surface while the incorporation of drug imparted a slight roughness to the surface. Optimized process and formulation parameters resulted in spherical shape and rigid surface, homogenous population of microspheres in the size range of 15.56 ± 37. 31 μm. The in vitro diffusion of PG from the prepared microspheres exhibited the extent of drug release decreased from 91–69%. The release of the drug has been controlled by swelling control release mechanism. No initial burst release has been recorded except for PG microspheres stabilized by using 25% w/v glutarldehyde as cross-linking agent. Modeling drug release from polymeric controlled drug delivery systems has led to a wide spectrum of mathematical models. The drug release from PG microspheres obeys Krosmeyer-Peppas model and non-Fickian diffusion pattern. Among the system examined glutaraldehyde cross linked microspheres show the highest release rate while the thermally cross linked microspheres had the lowest release rate, which is characterized by the longest lasting anomalous transport mechanism.