[Physico-chemical properties of 7-aminodesacetoxycephalosporanic acid]

7-Aminodesacetoxycephalosporanic acid (7-ADCA) of 99 per cent purity was prepared by enzymatic hydrolysis of 7-phenylacetamidodesacetoxycephalosporanic acid. Its isoelecti point was determined by the electrophoretic method. Potentiometric titration of zwitterion of 7-ADCA was performed and the constants of its ionization were calculated. Minimum solubility of 7-ADCA zwitterion was determined and the curve of 7-ADCA solubility at wide pH ranges was estimated. Equilibrium of 3 forms of 7-ADCA was estimated.