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Summary The effect of pH on the rate of hydrolysis of cocaine was investigated. Ionic strength had a negligible effect while the concentrations of the various buffers had a significant effect on the rate of hydrolysis. The pH rate profile in buffer showed a minimum at 1.95. The energies of activation were determined to be 95.9, 107.3 and 97.9 kJ mol‐1 respectively at pH 6.8, 5J0 and 2.2. The stability on storage of sterilized solutions of cocaine prepared by various methods and formulae was compared with the stability predicted from the results of the accelerated tests.

The effect of ascorbate and anaerobiosis of beta-lactamase content (constitutive and inducible) in relation to the susceptibility of a standard strain of Enterobacter cloacae to ampicillin was studied. Enterobacter cloacae ATCC 13047 showed increasing susceptibility to ampicillin when incubated anaerobically in the presence of increasing concentrations of ascorbic acid. The inducible beta-lactamase activity in the cell-free extracts of Ent. cloacae decreased when the bacterium was grown aerobically in the presence of ascorbic acid. Under anaerobic growth conditions, however, ascorbic acid abrogated the induction of the enzyme completely. On the other hand, the constitutive enzymatic activity was markedly decreased as the bacterium was grown anaerobically. Thus under these growth conditions ascorbate-anaerobiosis, the total beta-lactamase level in the presence of ampicillin as inducer fell below the basal constitutive activity observed in the absence of ampicillin.

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