Abstract

A simple, fast, precise and accurate liquid chromatographic method was developed for the simultaneous estimation of tizanidine, diclofenac potassium and paracetamol in tablets. This combination is used for spasm and pain associated with musculoskeletal disorders. Drugs are chromatographed on a reverse phase Luna C18 column using a mobile phase, 25 mM phosphate buffer (pH 7.0) and acetonitrile in the ratio of 40:60 v/v. Carbamazepine was used as an internal standard. The retention time of Tizanidine, Diclofenac potassium, Paracetamol and carbamazepine was 5.00, 8.61, 3.43 and 11.68 min respectively. The validation of the proposed method was also carried out. The method was found to be linear (correlation co-efficient r>0.999), precise (residual standard deviation: 0.51% for paracetamol, 0.42% for diclofenac potassium and 0.81% for tizanidine), accurate (overall average recovery yields: 99.0% for tizanidine, 99.3% for diclofenac potassium and 98.6% for paracetamol) and selective. Due to its simplicity and accuracy the proposed method can be used for routine quality control analysis of these drugs in combination tablets.