Estimation of Nateglinide and Metformin Hydrochloride in Tablet Dosage form by Spectrophotometric Methods

Three UV spectrophotometric methods have been developed for the simultaneous estimation of Nateglinide (Nat) and Metformin hydrochloride (Met) in combined tablet dosage form. The first method is the Area under curve method, the sampling wavelength ranges selected for estimation of Nat and Met are 214-216 nm and 231-235 nm respectively with linearity in the concentration ranges of 0.5-80 μg /ml and 0.5-40 μg/ ml respectively. Second method involves determination using the Multicomponent mode of the UV visible spectrophotometer, the sampling wavelengths selected are 216 nm and 233nm over the concentration range 0.5-80 μg/ml and 0.5-40 μg/ml for Nat and Met respectively. The third method is the second order derivative method, the sampling wavelengths selected for estimation of Nat and Met are 225 nm and 234 nm with linearity in the concentration range 1-70 μg/ml and 1-40 μg/ml respectively. The results of the analysis were validated statistically and recovery studies were carried out as per ICH guidelines. The developed methods are simple, rapid, precise, accurate and can be employed for the routine estimation of Nateglinide and Metformin hydrochloride in both bulk and tablet dosage form.