Visible spectrophotometric Methods for Estimation of Tizanidine from Bulk Drug and Formulation

Abstract

Three simple acid-dye colorimetric methods for estimation
of tizanidine, 5-chloro-N-(4,5-dihydro-1H-imidazol-2-yl) 2,1,3-
benzothiadiazol derivative which is mainly used as a centrally acting
skeletal muscle relaxant, have been developed. The developed
methods involve formation of coloured chloroform extractable complexes of
drug with bromocresol purple, bromocresol green and
bromophenol blue in acidic medium. Extracted complexes showed
absorption maxima at 417 nm, 415 nm and 414 nm and showed
linearity in concentration ranges of 2-10 mcg/mL, 4-20 mcg/mL
and 2-10 mcg/mL respectively. Results were validated statistically
and were found to be reproducible.