RESUMO
The dopamine derivatives participate in the regulation of a wide variety of physiological functions in human body and in medication life. A sensitive spectrophotometric method is developed for the determination of levodopa [LD], carbidopa [CD] and alpha methyldopa [MD]. It proposed on the bases of metal complex formation of these compounds with copper tetramine then coupling with 4-aminoantipyrine. The optimum conditions [pH, time, ratio and sequence of addition] are established. The method permits the determination of LD, CD and MD as a rectlinear relation in calibration curve over a concentration range 19.72 to 69.02, 13.79 to 63.34 and 31.24 to 98.94 micro g ml -1, respectively. The obtained data of SD [0.174 to 0.59], CV [0.68 to 1.16%] and correlation coefficient [0.995 to 0.999] reflect the reliability, reproducibility and accuracy of this procedure. The method is applicable to the assay of LD and MD in pharmaceutical drugs [Levocare and Aldomet respectively], and the results are in a good agreement with those obtained by the official method. The method was simple, rapid, reproducible and accurate to follow of medication of schizophrenic patient