Woolfrey S G, Taylor G, Kellaway I W, Smith A
J Pharm Pharmacol. 1986 Apr;38(4):304-6. doi: 10.1111/j.2042-7158.1986.tb04573.x.
The pulmonary absorption of the fluorescent marker 6-carboxyfluorescein (CF) has been characterized. CF was administered intratracheally (i.t.) as a fluid instillate to pentobarbitone-anaesthetized rats at doses of 0.5 and 2 mg kg-1. The absorption was characterized by both model-independent and model-dependent pharmacokinetic analyses of blood concentration data with reference to previous intravenous (i.v.) studies. The mean fraction available (F) of CF was 90 and 112% with a mean absorption time of 107 and 109 min for the lower and higher doses, respectively. The terminal half-life for the i.t. administered CF (73 and 83 min for the 0.5 and 2 mg kg-1 doses, respectively) was significantly longer (P less than 0.001) than after i.v. dosing (18 min). This indicates a slow pulmonary absorption of CF. Blood concentration-time profiles could not be adequately described by models involving a simple first-order absorption process; a model incorporating two simultaneous first-order inputs gave a much better description, its absorption rate constants differing by almost two orders of magnitude.
荧光标记物6-羧基荧光素（CF）的肺部吸收特性已得到表征。将CF以液体滴注的方式经气管内（i.t.）给予戊巴比妥麻醉的大鼠，剂量分别为0.5和2 mg kg-1。参照先前的静脉内（i.v.）研究，通过对血药浓度数据进行非模型依赖和模型依赖的药代动力学分析来表征吸收情况。较低剂量和较高剂量的CF平均可利用分数（F）分别为90%和112%，平均吸收时间分别为107和109分钟。经气管内给药的CF的末端半衰期（0.5和2 mg kg-1剂量分别为73和83分钟）明显长于静脉给药后的半衰期（18分钟）（P小于0.001）。这表明CF的肺部吸收缓慢。涉及简单一级吸收过程的模型无法充分描述血药浓度-时间曲线；一个包含两个同时进行的一级输入的模型给出了更好的描述，其吸收速率常数相差近两个数量级。
