Lucek R, Dixon R
Res Commun Chem Pathol Pharmacol. 1977 Sep;18(1):125-36.
A specific radioimmunoassay (RIA) for the determination in plasma of the widely used tricyclic antidepressant amitriptyline (AT) and its major metabolite nortriptyline (NT) has been developed employing 3H-AT as the radioligand and a rabbit antiserum to a bovine serum albumin conjugate of N-succinyl-nortriptyline. Although the antiserum cross-reacts almost equally well with AT and NT, specificity is achieved by selective extraction of each compound from plasma at a different pH. A unique aspect of the assay is that at no time during the entire extraction procedure is the AT or NT taken out of solution. Both compounds are back extracted from the organic phase into 0.1 N HC1 and the acid fraction subjected to RIA directly. The method has a limit of sensitivity of about 2 ng/ml using a 0.5 ml sample of plasma. Satisfactory agreement was obtained for plasma levels of AT and NT when determined by the RIA and a specific GC/MS procedure. The correlation coefficients were 0.89 and 0.98 for AT and NT, respectively. THE RIA has been used to measure steady-state levels of AT and NT in man after chronic administration of AT and following a single oral 75 mg dose. The method also lends itself for the specific determination of NT alone in subjects receiving therapeutic doses of NT.
已开发出一种特定的放射免疫分析方法（RIA），用于测定血浆中广泛使用的三环类抗抑郁药阿米替林（AT）及其主要代谢产物去甲替林（NT）。该方法采用³H-AT作为放射性配体，以及针对N-琥珀酰去甲替林与牛血清白蛋白偶联物的兔抗血清。尽管该抗血清与AT和NT的交叉反应几乎同样良好，但通过在不同pH值下从血浆中选择性提取每种化合物来实现特异性。该分析方法的一个独特之处在于，在整个提取过程中，AT或NT从未从溶液中取出。两种化合物都从有机相反萃取到0.1N盐酸中，酸相直接进行放射免疫分析。使用0.5ml血浆样本时，该方法的灵敏度极限约为2ng/ml。通过放射免疫分析和特定的气相色谱/质谱法（GC/MS）测定AT和NT的血浆水平时，结果吻合良好。AT和NT的相关系数分别为0.89和0.98。放射免疫分析已用于测量慢性服用AT后以及单次口服75mg剂量后人体中AT和NT的稳态水平。该方法也适用于在接受治疗剂量NT的受试者中单独特异性测定NT。
