MacCallum J, Cummings J, Dixon J M, Miller W R
Imperial Cancer Research Fund Medical Oncology Unit, Western General Hospital, Edinburgh, UK.
J Chromatogr B Biomed Appl. 1996 Apr 12;678(2):317-23. doi: 10.1016/0378-4347(95)00530-7.
Tamoxifen (TAM) is a triphenylethylene anti-oestrogen, commonly used in the treatment of breast cancer. Patients receiving tamoxifen therapy may experience both de novo and acquired resistance. As one of the mechanisms for this may be extensive peripheral bio-transformation of tamoxifen, there has been considerable interest in the pharmacokinetics and metabolism of tamoxifen. A reversed-phase high-performance liquid chromatography separation has been developed to determine the levels of tamoxifen and its major metabolites in human plasma. The method is highly sensitive (2 ng/ml) and selective for tamoxifen, cis-tamoxifen (CIS), 4-hydroxytamoxifen (4-OH) and desmethyltamoxifen (DMT). A micro Bondapak C18 10 microns column (30 cm x 3.9 mm I.D.) was used, with a mobile phase of methanol-1% triethylamine at pH 8 (89:11, v/v). Sample preparation was carried out using a C2 (500 mg sorbent, 3 ml reservoirs) solid phase extraction method, and extraction efficiencies were approximately 60% for TAM and its metabolites. Accuracy and precision, as determined by spiking plasma samples with a mixture of tamoxifen and its metabolites, ranged from 85-110% (+/- 5-10%) at 1 microgram/ml, 101-118% (+/- 8-20%) at 0.1 microgram/ml and 111-168% (+/- 43-63%) at 0.01 microgram/ml. Results from 59 patients show mean values of 54 ng/ml for 4-OH; 190 ng/ml for DMT; 93 ng/ml for TAM and 30 ng/ml for CIS (detected in three patients only). This methodology can be applied routinely to the determination of TAM and its metabolites in plasma from patients undergoing therapy.
他莫昔芬（TAM）是一种三苯乙烯类抗雌激素药物，常用于治疗乳腺癌。接受他莫昔芬治疗的患者可能会出现原发性和获得性耐药。其机制之一可能是他莫昔芬在外周广泛的生物转化，因此人们对他莫昔芬的药代动力学和代谢产生了浓厚兴趣。已开发出一种反相高效液相色谱分离法来测定人血浆中他莫昔芬及其主要代谢物的水平。该方法对他莫昔芬、顺式他莫昔芬（CIS）、4-羟基他莫昔芬（4-OH）和去甲基他莫昔芬（DMT）具有高灵敏度（2 ng/ml）和选择性。使用了一根10微米的微Bondapak C18柱（30 cm×3.9 mm内径），流动相为pH 8的甲醇-1%三乙胺（89:11，v/v）。采用C2（500 mg吸附剂，3 ml储液器）固相萃取法进行样品制备，他莫昔芬及其代谢物的萃取效率约为60%。通过向血浆样品中加入他莫昔芬及其代谢物的混合物来测定准确度和精密度，在1微克/毫升时范围为85 - 110%（±5 - 10%），在0.1微克/毫升时为101 - 118%（±8 - 20%），在0.01微克/毫升时为111 - 168%（±43 - 63%）。59名患者的结果显示，4-OH的平均值为54 ng/ml；DMT为190 ng/ml；TAM为93 ng/ml；CIS为30 ng/ml（仅在3名患者中检测到）。该方法可常规应用于测定接受治疗患者血浆中他莫昔芬及其代谢物的含量。
