Excretion of Piperazine Salts in Urine

Abstract

Urinary excretion of piperazine has not been widely studied owing to the lack of a quantitative method of analysis in biological fluids. A solution of potassium bismuth iodide gives a red precipitate with piperazine, and was used by Zimmermann (1901) for the qualitative demonstration of the drug. Nessler's reagent gives a heat-soluble precipitate; the picrate, chloroaurate, and platinate are also characteristic. Piperazine is precipitated by tannic acid, and can also be identified in urine by shaking a strongly alkaline sample with benzoyl chloride and determining the melting-point of the final product after crystallization in alcohol. Valseth and Wickstr6m (1954) The present paper describes a colorimetric method, using 1: 2-naphthoquinone-4-sulphonic acid (Folin's amino-acid reagent) for the quantitative determination of piperazine in urine. It is a modification of a procedure originally devised by Dr. Eileen Short (private communication), and, although it is not specific for piperazine, the method gives accurate results, and is suitable as a practical laboratory procedure involving the minimum number of manipulations. Amino-acids and other substances present in the urine also give coloured derivatives with the reagent, but the effect of interfering substances can be eliminated by using internal standards in a manner similar to that of Harris and Raymond (1939) for the determination of nicotinic acid. The method has been employed to study the excretion rates in human subjects after oral doses of piperazine. The results include a small number of excretion values from Africans infected with ascarides. 2-.