The objective of the present study was to prepare the mucoadhesive microspheres of simvastatin to provide oral controlled release.Mucoadhesion had been a topic of interest in the design of drug delivery system to prolong the residence time of the dosage form with the underlying absorption surface to improve and enhance the bioavailability of drugs. The simvastatin loaded mucoadhesive microspheres were prepared by the Orifice – Ionic gelation method using mucoadhesive polymers such as Sodium alginate, Carbopol, HPMC K100, Sodium CMC, Ethyl cellulose, Methyl Cellulose, Guar gum, and Xanthan gum in different ratios.The calcium chloride was used as the cross linking agent.The microspheres were discrete, spherical, free flowing, exhibited drug content uniformity and high entrapment efficiency.The simvastain release from the microspheres was slow and extended up to 8 hours.The drug release from the optimized formulation(drug-sodium alginate-methyl cellulose;1:2:1 ratio) followed zero order kinetics and exhibited non-fickian diffusion. The microspheres exhibited good mucoadhesive property in the in vitro wash-off test.The FTIR analysis of drug, polymers and the optimized formulation indicated the compatibility of the drug with the polymers.The sphericity and smoothness of microspheres were confirmed by scanning electron microscopy(SEM).The differential scanning calorimetry(DSC)studies indicated the absence of drug-polymer interaction in the microspheres.The present study concludes that the mucoadhesive microspheres can be considered as a promising oral controlled release dosage form for simvastatin.
Keywords: Simvastatin, Mucoadhesive microspheres, In-vitro wash off method.