Development of Orodispersible Tizanidine HCl Tablets Using Spray Dried Coprocessed Exipient Bases

Tizanidine HCl is a centrally acting α-2 adrenergic agonist muscle relaxant with a slightly bitter taste having short half-life of 2.5 h. In the present study effect of co-processed excipient bases in formulation of orodispersible tizanidine HCl tablets by direct compression method was investigated. Co-processed excipient of microcrystalline cellulose with SSL-hydroxypropylcellulose was prepared using spray drier in 1:1, 1:2 and 1:3 ratio. Formulated tablets were evaluated for hardness, friability, in vitro disintegration time and in vitro drug release. Formulation F-3 prepared by addition of co-processed excipient base in ratio of 1:3 showed minimum disintegration time of 9.15±0.04 s and higher amount of drug release of 93.75% at the end of 15 min. Granules obtained by spray drying technique were found to be more spherical which improved its flow property and was supported by scanning electron microscope studies. Thermal studies indicated change in amorphous state, compatibility of drug in formulation was confirmed by fourier transform infrared studies. Analyses of drug release data indicated formulation followed first order kinetics. Inclusion of co-processed excipient base in formulation of orodispersible tablets enhanced disintegration significantly.