Serum Propylthiouracil: Determination by a Direct Colorimetric Procedure

Abstract

Abstract A direct colorimetric method is described for the determination of propylthiouracil in serum, which is based on reaction of the drug at pH 8.0 with 2,6-dichloroquinone-chloroimide to produce a colored chloroform-soluble compound. After isolation from the aqueous layer with phase-separating filter paper, the chloroform solution is read against a chloroform blank at 435 nm. Propylthiouracil added to drug-free serum serves as a control sample. The method obeys Beer's law up to a concentration of at least 10 mg/liter.