무염 원자흡광도법과 흡광광도법에 의한 제제중의 Metoclopramide의 정량

Determination of Metoclopramide by Flameless Atomic Absorption and Spectrophotometry

Metoclopramide reacts with ammonium cobaltothiocyanate to form a stable ion pair which has an absorption maximum of 625nm. The reaction product was insoluble in water but soluble in most organic solvents. 1,2-Dichloroethane was the best extracting solvent among the several organic solvents tested. Metoclopramide can be determined not only by visible light spectrophotometry but also indirectly by estimation of cobalt in the organic phase by flameless atomic absorption spectrophotometry. Linear relationship was found between absorbance and concentration in the range of 10-4~10-3M by spectrophotometry and 10-5~10-4M by flameless atomic absorption spectrophotometry. The coefficient of variation by spectrophotometry was 0.9% and that of flameless atomic absorption was 1.8%. There was no interference with excipients, pH, temperature and reaction time. With this method, it is possible to determine accurately metoclopramide and tertiary amines in pharmaceutical preparations.