Cephradine excretion in humans with pH-altered urine.

In a random crossover study, ten healthy men were pretreated with ammonium chloride or sodium bicarbonate to alter urinary pH, and then were given a single 1-Gm dose of cephradine, either orally or intravenously. No significant changes were found in the terminal phase rate constant nor in the time or magnitude of peak concentration. Total recovery was greater than 90 per cent whenever degradation of cephradine did not occur. An unexplained but significant reduction in area under curve was present in data for prealkalinized subjects and for all subjects who took cephradine orally. Trapping of cephradine was not significant in the excretory pathway.