代谢
血液-视网膜和血液-房水屏障对荧光素的渗透性以及房水流动速度可以通过系统给药后在玻璃体、房水和血浆中测量荧光素来估计。荧光素通常通过荧光法测量,但荧光素的代谢物荧光素葡萄糖醛酸也具有荧光性。为了评估荧光素葡萄糖醛酸对荧光法测定荧光素的影响,我们研究了五名正常受试者静脉注射14 mg/kg的荧光素钠后,血浆中荧光素和荧光素葡萄糖醛酸的药代动力学,持续时间为38小时。血浆和血浆超滤液通过荧光法和高效液相色谱法进行测量。在我们的荧光光度计中,荧光素葡萄糖醛酸的荧光强度是荧光素的0.124倍。荧光素迅速转化为荧光素葡萄糖醛酸,在10分钟内,未结合的荧光素葡萄糖醛酸浓度超过了未结合的荧光素。血浆超滤液中荧光素和荧光素葡萄糖醛酸的终末半衰期分别为23.5分钟和264分钟,因此在大约4-5小时后,血浆荧光几乎全部由荧光素葡萄糖醛酸贡献。由于血浆中荧光素葡萄糖醛酸的绑定程度低于荧光素,随着时间的推移,血浆超滤液的荧光强度与血浆的比值增加。注射后不久,渗透到眼内腔室的荧光素总量达到最大比例...
The permeability of the blood-retinal and blood-aqueous barriers to fluorescein and the rate of aqueous flow can be estimated by measurements of fluorescein in the vitreous, aqueous, and plasma after systemic administration. Fluorescein is commonly measured by fluorescence, but fluorescein glucuronide, a metabolite of fluorescein, also fluoresces. To assess the influence of fluorescein glucuronide on the quantitation of fluorescein by fluorescence, we studied the pharmacokinetics of fluorescein and fluorescein glucuronide for 38 hr in the plasma of five normal subjects given 14 mg/kg of sodium fluorescein intravenously. The plasma and the plasma ultrafiltrate were measured by fluorescence and by high performance liquid chromatography. In our fluorophotometer, fluorescein glucuronide was 0.124 times as fluorescent as fluorescein. Fluorescein was rapidly converted to fluorescein glucuronide, and within 10 min the concentration of unbound fluorescein glucuronide exceeded that of unbound fluorescein. The terminal half-lives of fluorescein and fluorescein glucuronide in the plasma ultrafiltrate were 23.5 and 264 min, respectively, so that fluorescein glucuronide contributed almost all of the plasma fluorescence after 4-5 hr. Because fluorescein glucuronide was less bound in the plasma than fluorescein, the ratio of the fluorescence of the plasma ultrafiltrate to that of the plasma increased with time. The greatest proportion of the total fluorescein available to penetrate into the ocular compartments occurred shortly after injection. ...
来源:Hazardous Substances Data Bank (HSDB)