A chemical method for the determination of natural and semisynthetic penicillins in biological material

Abstract

1. 1. A simple and accurate method for the determination of penicillins in aqueous solutions and biological material (tested for urine) was elaborated. It is based on the hydrolysis of the extracted penicillin to penicillamine and on the amperometric titration of the -SH group of penicillamine. The technique estimates only the biologically active forms of penicillin and not the degradation products. 2. 2. The technique in its described version without extraction may be used directly for aqueous solutions of penicillins. Extraction with chloroform is needed for the determination in biological material. (Tested for penicillin G, penicillin V, Maxipen Ultrapen, Celbenin, Prostaphlin). Further penicillin preparates can be determined most probably on the basis of this method. 3. 3. Penbritin may be determined either directly without extraction in aqueous solutions, or after extraction with N- butanol in biological material. 4. 4. The results of reproducibility and recovery studies show the high accuracy of the method. 5. 5. The presented chemical method for penicillin determination is in good agreement with the microbiological assay as confirmed by parallel determinations in the same urine specimen.