Spectrophotometric determination of diphenhydramine with Plasmocorinth B

Abstract

Diphenhydramine, an antihistaminate, reacts with Plasmocorinth B (abbreviated as PCB) to form a product extractable in chloroform. The extractability reaches maximum at pH between 2.0 and 3.0, and the extarct shows absorption maxima at 540 mμ and 567 mμ. The amount of PCB should be more than 10 times that of equivalent, whereby the absorbance at 540 mμ obeys Beer's law.
Influences of temperature and time together with various extracting conditions were examined, and a satisfactory procedure for the determination has been established. The method is relatively simple and quite accurate.