Földesi I, Falkay G, Kovács L
Szent-Györgyi Albert Orvostudományi Egyetem Szülészeti és Nögyógyászati Klinika, Szeged.
Acta Pharm Hung. 1994 Jan;64(1):17-21.
The pharmacokinetics of RU 486 and its active metabolites were studied in 31 women who received a single oral dose of 200 mg (n = 9), 400 mg (n = 10) or 600 mg (n = 12) of RU 486 for termination of an early unwanted pregnancy. The serum levels were measured within 48 hours after the intake by radioligand binding assay using human myometrial cytosolic progesterone receptor as binding protein. The assay is based on the competitive replacement of 3H-ORG-2058 by the active molecular fraction of RU 486 present in the serum. The results were expressed as RU 486 equivalent. It was found that pharmacokinetics of the RU 486 equivalent followed two-compartment open model. The pharmacokinetic parameters were calculated by MEDUSA computer programme. Rapid absorption and distribution was followed by relatively slow elimination. The elimination half-life ranged between 80-90 hours. No significant difference was found between the parameters of the absorption distribution and elimination processes of three different doses. Thus, the RU 486 equivalent followed first-order kinetic. Peak serum concentrations were reached within 1-2 hours after the ingestion of the drug. Significant differences were found between 200 and 600 mg doses in the peak plasma values (p < 0.05) and in the areas under the curve (p < 0.01). However, these differences were not directly proportional to the increase of the dose.
在31名接受单次口服200毫克（n = 9）、400毫克（n = 10）或600毫克（n = 12）RU 486以终止早期意外妊娠的女性中，研究了RU 486及其活性代谢物的药代动力学。在服药后48小时内，使用人子宫肌层胞质孕酮受体作为结合蛋白，通过放射性配体结合测定法测量血清水平。该测定基于血清中存在的RU 486活性分子部分对3H-ORG-2058的竞争性置换。结果以RU 486当量表示。发现RU 486当量的药代动力学遵循二室开放模型。药代动力学参数通过MEDUSA计算机程序计算。快速吸收和分布之后是相对缓慢的消除。消除半衰期在80 - 90小时之间。三种不同剂量的吸收、分布和消除过程参数之间未发现显著差异。因此，RU 486当量遵循一级动力学。服药后1 - 2小时内达到血清峰值浓度。200毫克和600毫克剂量之间在血浆峰值（p < 0.05）和曲线下面积（p < 0.01）方面存在显著差异。然而，这些差异与剂量增加并非直接成比例。
