Stability of Potassium Phenethicillin I.

β-Lactam Antibiotics: Their Physicochemical Properties and Biological Activities in Relation to Structure

“…The degradation kinetics of phenethicillin in a pH range of 1-11.4, with a constant ionic strength of 0.5 and at 35", was reported by Schwartz et al (142). The apparent pH of minimum degradation occurred 0 b X C 0 , H xx at about 6.5.…”

Kinetics and Mechanism of Degradation of Ampicillin in Solution

“…The kinetics of penicillin G reactions have been reported earlier by Brodersen (7,8); Schwartz has published the kinetics of phenethicillin (9). The general acid-base catalytic effect and salt effect on the degradation of penicillin G has recently been reported by Finholt et al (10).…”

“…Schwartz el al. (9) reported the activation energy for phenethicillin at pH 6.6 to be 17.6 kcal./mole. Doyle et al (1) determined the acid stabili- 1 The procedures used to determine the dissociation constants were essentially the same as that reported by Rapson and Bird (6).…”

Chemical Aspects of Penicillin Allergy

“…The previously neglected metabolism of these drugs requires more attention, particularly with regard to characterization of products rather than rates. Stability studies on penicillins, e.g., benzylpenicillin (127, 128), phenethicillin (129), and methicillin (130), which have in the past been primarily directed toward determination of rate of loss from solution, should focus more attention in the future upon products of degradation, their formation rates, and their ability to react with protein. This information would be of value in assessing the potential antigenicity of new penicillins and in formulating products so that rates of degradation to reactive intermediates might be minimized.…”