Chemical analysis of some penicillin and cephalosporin drugs

Abstract

This thesis describes work on the polarographic analysis of penicillin and cephalosporin antibiotics. Methods for the quantitative analysis of Ampicillin, Amoxycillin and Cephalexin were developed. These methods are based on the formation of Ni(II) or Co(II) complexes of the antibiotics or on degradation products namely, 2,5-diketopiperazine derivatives. The optimum conditions of buffering, support electrolyte, pH, temperature and the effect of time were studied for the Ni(II) complexes of Ampicillin and Amoxycillin. Under these optimum conditions, linear calibration ranges were 5.00 x 10 to 1.00 x 10 M and 4.00 x 10 to 2.00 x 10 for Ampicillin and Amoxycillin respectively. Reversibility tests suggest that the electrode reactions are probably reversible and they are one electron transfer processes. The Co(II) complex of Cephalexin was compared with that of Ni(II)_ for the analysis and found to be inferior. A satisfactory method based on the formation of the 2,5-diketopiperazine derivatives of Amoxycillin was developed. The methods devised were tested on pharmaceutical products (capsules) and the results compared with pharmacopoeia methods. Good agreement was obtained.