Study of Mucoadhesive Microspheres of Metoprolol Tartarate Based on Crosslinked Tapioca Starch as New Carrier for Drug Delivery

Abstract

Bioadhesive metoprolol-loaded microspheres were prepared by ionic-gelation technique using combination of sodium alginate and tapioca starch as retardant materials to reduce dose frequency, thereby improve patient compliance. The formulation variables were tapioca starch concentration, drug loading, and stirring speed. The microspheres were evaluated for characteristics, like entrapment efficiency, particle size, swelling ability, mucoadhesive property, surface characteristics, in-vitro drug release, and in-vivo pharmacodynamic performance in rabbits against isoprenaline-induced tachycardia. Infrared spectroscopic study confirmed the absence of any drug-polymer interaction. Dfferential scanning calorimetric analysis revealed that the drug was molecularly dispersed in the microspheres matrices showing rough surface which was confirmed by scanning electron microscopy study. The mean particle size and entrapment efficiency were found to be varied by changing various formulation parameters. The in-vitro release profile could be altered significantly by changing various formulation parameters to give a sustained release of drug from the microspheres. Treatment of in-vitro data to different kinetic equations indicated matrix-diffusion controlled drug delivery from microspheres. The in-vivo studies indicated the sustained and controlled inhibition of isoprenaline-induced tachycardia of microspheres compared with oral administration of drug solution.