UV spectrophotometric method for simultaneous estimation of tizanidine and valdecoxib in tablet dosage forms

Pranav Institute of Pharmaceutical Sciences, Sitholi, Gwalior-474 011, Madhya Pradesh, India E-mail : sharma.radha@rediffmail.com Department of Pharmaceutical Sciences, Dr. H. S. Gour Vishwavidhyalaya, Sagar-470 003, Madhya Pradesh, India Manuscript received 3 December 2007. revised 6 February 2009, accepted 31 March 2009 The simple, selective, rapid and precise UV spectrophotometric method has been developed for the simultaneous estimation of valdecoxib and tizanidine in pharmaceutical dosage form. The proposed method is based on the Vierodt's simultaneous equations. Tizanidine has absorption maxima at 318.1 nm and valdecoxib absorption maxima at 239.0 nm in methanol. The linearity was observed In the concentration range of l-18 µg/ml for tizanldine and valdecoxib. Both the drugs obey Beer's law. The method is validated statistically. The recovery studies confirmed the accuracy of the proposed method