Inactivation of Penicillins by Carbohydrate Solutions at Alkaline pH

Penicillin and semisynthetic penicillins are biologically inactivated by carbohydrate solutions at alkaline pH. At 37°C, in the presence of sufficient bicarbonate to elevate the pH above 8.0, 10 per cent sucrose and 5 per cent glucose cause almost complete inactivation of penicillin within a few hours; inactivation occurs more slowly at room temperature. Semisynthetic penicillins are similarly inactivated. Penicilloic acid appears to be the major product of inactivation. Thus, under clinical conditions in which penicillin is administered in solutions containing both carbohydrate and alkaline buffer, there is risk of losing antibiotic activity and forming allergenic derivatives of penicillin.