Structures and fluids involved in the penetration of topically applied drugs.
Structures and fluids involved in the penetration of topically applied drugs.
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参与局部药物渗透的结构和液体。
DOI：
10.1097/00004397-198002030-00004
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发表时间：
1980
影响因子：
--
通讯作者：
Maurice,DM
中科院分区：
文献类型：
--
作者：
Maurice,DM
要了解药物从滴眼液到靶点的运动，只能基于对组织屏障和储存库以及它们之间的液体排出系统的考虑。当药物在泪液中时，动力学是相当简单的，但例如在睫状体中就不太清楚了。当一滴药物溶液滴入眼内时，其通过前部结构的渗透被认为发生在两个阶段：进入组织时的渗透期和洗出时的下降期。在穿透阶段进入角膜的量由它与角膜接触的时间决定，并由泪液动力学和角膜上皮的渗透性控制。药物在角膜中的浓度在几分钟内接近峰值，然后继续渗透到前房。如果角膜内皮通透性低，房水中的积聚由其自身的周转率控制，将需要长达2小时的时间才能达到峰值。另一方面，如果内皮通透性高，房水浓度可以在10到20分钟内达到最大值，在下降阶段，角膜可能起到蓄水池的作用，以决定眼睛浓度下降速度的速率逐渐释放药物。在另一个极端，角膜可能与房水达到平衡，因此浓度下降的速度将由来自An-An的损失系数确定。
An understanding of the movement of a drug from an eyedrop to its target can be based only on a consideration of tissue barriers and depots and of the fluid drainage systems that stand between them. The kinetics are fairly straightforward when the drug is in the tear fluid, but they are less well understood in the ciliary body, for example. When a drop of drug solution is instilled into the eye, its permea-tion through the anterior structures is considered to take place in two phases: the penetrating phase when it is entering the tissues, and the declining phase when it is washing out. The amount entering the cornea during the penetrating phase is determined by the time during which it is in contact with the cornea, and is controlled by both tear fluid dynamics and the permeability of the corneal epithelium. The concentration of a drug in the cornea approaches its peak within a few minutes, and then penetration continues into the anterior chamber. If permeability of the corneal endothelium is low, the build-up in the aqueous humor is controlled by its own turnover rate and will take up to 2 hours to peak. If endothelial permeability is high, on the other hand, aqueous concentration can rise to its maximum in from10 to 20 minutes, During the declining phase the cornea may act as a reservoir, grad-ually releasing the drug at a rate that determines how slowly the concentration in the eye falls. At the other extreme the cornea may come into equilibrium with the aqueous humor, so that the rate of decline in concentration will be determined by the loss coefficient from the an-