Formulation And Evaluation of Microsponges Containing BCS Class II Drug

Tizanidine Hydrochloride (TZH) is a short acting skeletal muscle relaxant. The bioavailability ranges between 30-40% and it has a half-life of 2.5 hours. Microsponges loaded in an emulgel for topical application offers several advantages over the oral administration of the drug. The aim of the study was to formulate microsponges of Tizanidine HCl (TZH) and to incorporate it into an emulgel to sustain the release of the drug. The study utilized Quasi-emulsion solvent diffusion technique to formulate microsponges with varying concentrations of Ethylcellulose (EC) and Polyvinyl Alcohol (PVA). The optimized TZH microsponges were characterized for Particle size, PDI, Zeta potential which depicted the narrow particle size distribution and high stability of the formulated microsponges and the DSC, XRD, FTIR studies confirmed the complete encapsulation of TZH and transformation to amorphous state. in-vitro dissolution studies showed sustained release of the drug. The optimized microsponges were loaded into an emulgel base which exhibited effective and extended drug release of 69.97% at the end of 8 h and showed no signs of irritation in the Wistar Albino rats. The results indicate that the TZH-microsponges have the potential to provide sustained release of the drug and thus will improve bioavailability and patient compliance.