Liquid Chromatographic Method for the Determination of Content Uniformity of Tetrabenazine

The study is a proposition of the application of high performance liquid chromatography (HPLC) with a spectrophotometric UV range detector to analyse the chemical purity and assay of tetrabenazine in bulk drug and tablet formulation and also to apply the proposed method to determine the content uniformity according to USP specification. During computer assisted literature search only a few publications were found about tetrabenazine, so the ultimate objective of the present investigation was aimed to develop stability - indicating LC method and the development of the newer analytical method was achieved under optimised chromatographic conditions by using mobile phase composed of potassium phosphate buffer: acetonitrile in the ratio (40:60v /v). The seperation was achieved by using isocratic elution mode with a flow rate of 1.0 mL/min. The effluent was monitored on a UV detector at 284 nm. The retention time of tetrabenazine was found to be at 5.05min and the standard calibration curve was linear over a concentration range of 6.25-37.5 μg/mL with r value of 0.999. The LOD and LOQ were found to be 0.562 and 1.704 μg/mL respectively. The recovery studies were performed and the percentage recoveries were found to be in the range of 98.64-98.88 %. The drug was also subjected to acidic, basic, oxidative and photolytic degradation as per the ICH guidelines. The developed method allows to separate all degradation from tetrabenazine and to quantitate the tetrabenazine amount. As there is no official monograph in the pharmacopeias about tetrabenazine, the performed full validation procedure makes the method ready to use in routine analysis.