Preparation of O- palmitoyl pullulan micro spheres for the controlled release of hydrophillic drug: verapamil hydrochloride

Abstract

The aim of the present investigation is to study potential of O-Palmitoyl pullulan (OPP) as a vehicle for the preparation of microspheres. In the first phase of the work the drug Verapamil hydrochloride and polymer compatibility studies is carried. Then O- Palmitoyl pullulan (OPP) is synthesised from pullulan and characterised by NMR spectrum. The microspheres of Verapamil HCl are prepared by employing the combined solution mixture of sodium alginate and O- Palmitoyl pullulan by Orifice- ionic gelation technique. The microspheres are evaluated for percentage yield, swelling index, entrapment efficiency etc. Extensive experimentation, in-vitro methods have been carried out.  It was observed that more than 90% of drug is released by 10-11 hr itself. Another formulation with further increased concentration of Sodium alginate is prepared. In this formulation, drug release is more sustained up to 12 hr. Formulations followed first order release kinetics and they showed Fickian type of diffusion. The stability studies revealed that there is no change in the drug release profile after the products are stored at 37+2⁰C and 75 + 5% RH and there was no significant drug loss after storage.