Eckert H G, Münscher G, Oekonomopulos R, Strecker H, Urbach H, Wissmann H
Arzneimittelforschung. 1985;35(8):1251-6.
A radioimmunoassay (RIA) has been developed for the measurement of 2-[N-[(S)-1-ethoxycarbonyl-3-phenylpropyl]-L-alanyl]-(1S,3S,5S)- 2-azabicyclo[3.3.0]octane-3-carboxylic acid (ramipril, Hoe 498) and its active metabolite (diacid: hydrolysis product of ramipril) in serum or plasma. Antibodies to the diacid were raised in rabbits against a lysine analogue conjugated to bovine serum albumin. A 125I-ramipril-diacid derivative was used as radioligand. Separation of the antibody-bound and free radiolabeled ligand was achieved by employing a polyethylene glycol solution. The RIA is specific for the active metabolite (diacid). Studies on specificity showed less than 0.6% cross-reactivity with intact ramipril or with dioxopiperazine metabolites. The levels for intact ramipril were obtained by prior enzymatic hydrolysis to the diacid. The sensitivity of the assay was 0.1 and 0.5 ng/ml for diacid and ramipril, respectively. Intra- and inter-assay coefficients of variation ranged from 3 to 14% at 1 to 30 ng diacid per ml. A recovery experiment yielded an average of 103%. The assay has been used to investigate the pharmacokinetic profile of both ramipril and its pharmacologically active metabolite.
已开发出一种放射免疫分析法（RIA），用于测定血清或血浆中的2-[N-[(S)-1-乙氧羰基-3-苯基丙基]-L-丙氨酰]-(1S,3S,5S)-2-氮杂双环[3.3.0]辛烷-3-羧酸（雷米普利，Hoe 498）及其活性代谢物（二酸：雷米普利的水解产物）。针对与牛血清白蛋白偶联的赖氨酸类似物，在兔体内制备了针对二酸的抗体。使用125I-雷米普利-二酸衍生物作为放射性配体。通过使用聚乙二醇溶液实现抗体结合的和游离的放射性标记配体的分离。该RIA对活性代谢物（二酸）具有特异性。特异性研究表明，与完整的雷米普利或二氧哌嗪代谢物的交叉反应率低于0.6%。完整雷米普利的水平通过预先酶解为二酸来获得。该分析方法对二酸和雷米普利的灵敏度分别为0.1和0.5 ng/ml。在每毫升含1至30 ng二酸的情况下，批内和批间变异系数范围为3%至14%。回收率实验平均为103%。该分析方法已用于研究雷米普利及其药理活性代谢物的药代动力学特征。
