A PAPER CHROMATOGRAPHIC METHOD FOR THE QUANTITATIVE ESTIMATION OF PENICILLIN ENTITIES

Abstract

A simple, direct method for the quantitative estimation of penicillin entities in broth is presented. The method, requiring 24 hrs. for a complete analysis, is based on the fact that the various penicillins possess different distribution coefficients between ether and phosphate buffer at a given pH and can be separated by using paper strip partition chromatography. After incubating the ether-developed strips on agar seeded with Staphylococcus aureus 209P for 16 hrs. at 37[degree]C, a quantitative estimation of activity percentage is obtained by measuring the minor axis of the individual zones, reading the equivalent penicillin unitage from a standard curve, and dividing the units of each penicillin by the total units found. In the analysis of 35 known penicillin mixtures in buffer and 24 in broth, the difference between the percentage of the various penicillins added and the percentage found did not exceed 13%, and the avg. difference did not exceed [plus or minus]15%. Data and shadowgraphs are presented indicating the precision of the method.