Musher D M, Griffith D P
Antimicrob Agents Chemother. 1974 Dec;6(6):708-11. doi: 10.1128/AAC.6.6.708.
Using an in vitro system that simulates the dynamics of the urinary tract, we have shown that concentrations of formaldehyde >/= 25 mug/ml can be achieved in urine containing >/= 0.6 mg of methenamine per ml at pH </= 5.7 or >/= 1 mg/ml at pH </= 5.85. Exposure to this concentration of formaldehyde for 2 h produced a measurable antibacterial effect. These studies suggest that an effective bacteriostatic level of formaldehyde is likely to be achieved with currently used dosages of methenamine when the urine pH is less than 5.7 to 5.85.
通过使用一种模拟尿路动力学的体外系统,我们已经表明,在pH≤5.7时,每毫升含≥0.6毫克乌洛托品的尿液中可达到≥25微克/毫升的甲醛浓度;在pH≤5.85时,每毫升含≥1毫克乌洛托品的尿液中也可达到该浓度。暴露于这种浓度的甲醛2小时会产生可测量的抗菌效果。这些研究表明,当尿液pH小于5.7至5.85时,目前使用的乌洛托品剂量可能会达到有效的甲醛抑菌水平。