Joqueviel C, Gilard V, Martino R, Malet-Martino M, Niemeyer U
Laboratoire des IMRCP, Université Paul Sabatier, Toulouse, France.
Cancer Chemother Pharmacol. 1997;40(5):391-9. doi: 10.1007/s002800050676.
Phosphorus-31 nuclear magnetic resonance spectroscopy was used to evaluate the stability of carboxycyclophosphamide (CXCP) and carboxyifosfamide (CXIF) in human urine at pH 7.0 and 5.5 at 25 degrees, 8 degrees, -20 degrees, and -80 degrees C. At 25 degrees C and pH 7.0, CXCP and CXIF are relatively stable (approximately 10% degradation in 24 h). In contrast, they are much less stable at pH 5.5 (approximately 80% degradation of CXIF and approximately 50% degradation of CXCP in 24 h). The rate of degradation of CXCP and CXIF was a function of the storage temperature of the urine samples but, even at -80 degrees C, was not negligible: approximately 30% degradation for CXCP irrespective of pH and approximately 40% and 50% degradation for CXIF at pH 7.0 and 5.5, respectively, after storage for 6 months. CXCP was more stable than CXIF at either pH (7.0 or 5.5) and at all storage temperatures (8 degrees, -20 degrees, or -80 degrees C) of the urine samples. CXCP and CXIF were more stable at pH 7.0 than at pH 5.5, although this difference fell with decreasing temperatures to be almost negligible at -80 degrees C. To ensure a true estimate of CXCP and CXIF levels, urine samples must be frozen and stored at -80 degrees C within a few hours of micturition. CXCP and CXIF assays should also be carried out within 2 months and 1 month of storage, respectively.
采用磷-31核磁共振波谱法评估了羧基环磷酰胺（CXCP）和羧基异环磷酰胺（CXIF）在25℃、8℃、-20℃和-80℃下，pH值为7.0和5.5的人尿液中的稳定性。在25℃和pH值为7.0时，CXCP和CXIF相对稳定（24小时内降解约10%）。相比之下，它们在pH值为5.5时稳定性要低得多（24小时内CXIF降解约80%，CXCP降解约50%）。CXCP和CXIF的降解速率是尿液样本储存温度的函数，但即使在-80℃时，降解也不可忽略：储存6个月后，无论pH值如何，CXCP降解约30%，在pH值为7.0和5.5时，CXIF分别降解约40%和50%。在尿液样本的任何pH值（7.0或5.5）以及所有储存温度（8℃、-20℃或-80℃）下，CXCP都比CXIF更稳定。CXCP和CXIF在pH值为7.0时比在pH值为5.5时更稳定，尽管随着温度降低这种差异减小，在-80℃时几乎可以忽略不计。为确保对CXCP和CXIF水平的真实估计，尿液样本必须在排尿后数小时内冷冻并储存在-
