Development of a Quantitative Spectrophotometric Determination Method for Papaverine in Medicinal Preparations

Resumo

A quantitative spectrophotometric determination method for papaverine in medicinal preparations based on formation of a colored ionic associate of papaverine, Ti(IV), and bromopyrogallol red (BPR) was developed. The conditions for forming {[TiO(H₂R)₂]^2– · 2PP⁺} were determined. Addition of papaverine to a solution of anionic Ti-BPR caused a bathochromic shift to 640 nm with a simultaneous intensity gain. The molar absorption coefficient (ε = 8,800) indicated that the reaction was rather sensitive. The specificity of the reaction for papaverine enabled it to be determined without separating excipients. The method was highly sensitive, simple to perform, and adaptable to scale up. Toxic reagents were not required. The results had good precision (S_r = 0.007 – 0.02) and accuracy.