Simultaneous determination of levodopa and carbidopa in levodopa-carbidopa tablets by ATR-FTIR spectrometry.

A novel analytical procedure has been developed for quantitative determination of levodopa and carbidopa in aqueous binary solutions acidified by HCl and without any other sample pretreatment. The method is based partially on least squares treatment of data obtained by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectrometry in 1211-1315 cm(-1) and 1488-1550 cm(-1) spectral regions. The simple, rapid, and accurate proposed method was applied to determine levodopa and carbidopa in Levodopa-C tablets. The statistical parameters, such as R2, RSD, SEE, SECV, LOD, and recovery were evaluated. Number of factors, scans, and resolution were optimized. In this method R2 and RSD for levodopa and carbidopa were (0.9965, 1.209) and (0.9537, 0.813), respectively.