Larsson C I
Department of Pharmacology & Toxicology, Faculty of Veterinary Medicine, Swedish University of Agricultural Sciences, Uppsala.
Life Sci. 1991;49(13):PL73-8. doi: 10.1016/0024-3205(91)90082-m.
Microdialysis of intravenously injected theophylline in blood and in lung tissue was performed in two rats during anaesthesia. The recovery (dialysate extraction fraction) in blood was greater than the recovery in lung tissue and there was a change in recovery with time both in blood and in lung. The concentrations of theophylline in the dialysates were corrected for the recovery using caffeine as an "internal standard" in the perfusate as well as tritiated water injected into the rats. There was excellent agreement between the two different methods. Furthermore, the corrected concentration of unbound theophylline in the blood was in accordance with the simultaneously measured total concentration of theophylline in plasma when binding to plasma proteins was taken into account. The conclusion is that an "internal standard" for correction of the recovery is a useful method to approach the true concentrations of compounds in the extracellular water. The "internal standard" must be as equal as possible to the substance of interest.
在麻醉状态下，对两只大鼠进行了静脉注射氨茶碱后在血液和肺组织中的微透析实验。血液中的回收率（透析液提取分数）高于肺组织中的回收率，并且血液和肺中的回收率均随时间变化。使用灌注液中的咖啡因作为“内标”以及注入大鼠体内的氚水对透析液中氨茶碱的浓度进行回收率校正。两种不同方法之间具有极好的一致性。此外，当考虑到与血浆蛋白的结合时，校正后的血液中游离氨茶碱浓度与同时测量的血浆中氨茶碱总浓度一致。结论是，用于校正回收率的“内标”是一种接近细胞外液中化合物真实浓度的有用方法。“内标”必须尽可能与目标物质相同。
