Ranade V V
Action Medical Marketing Co. Libertyville, Illinois.
J Clin Pharmacol. 1991 May;31(5):401-18. doi: 10.1002/j.1552-4604.1991.tb01895.x.
Transdermal drug delivery system has been in existence for a long time. In the past, the most commonly applied systems were topically applied creams and ointments for dermatological disorders. The occurrence of systemic side-effects with some of these formulations is indicative of absorption through the skin. A number of drugs have been applied to the skin for systemic treatment. In a broad sense, the term transdermal delivery system includes all topically administered drug formulations intended to deliver the active ingredient into the general circulation. Transdermal therapeutic systems have been designed to provide controlled continuous delivery of drugs via the skin to the systemic circulation. The relative impermeability of skin is well known, and this is associated with its functions as a dual protective barrier against invasion by micro-organisms and the prevention of the loss of physiologically essential substances such as water. Elucidation of factors that contribute to this impermeability has made the use of skin as a route for controlled systemic drug delivery possible. Basically, four systems are available that allow for effective absorption of drugs across the skin. The microsealed system is a partition-controlled delivery system that contains a drug reservoir with a saturated suspension of drug in a water-miscible solvent homogeneously dispersed in a silicone elastomer matrix. A second system is the matrix-diffusion controlled system. The third and most widely used system for transdermal drug delivery is the membrane-permeation controlled system. A fourth system, recently made available, is the gradient-charged system. Additionally, advanced transdermal carriers include systems such as iontophoretic and sonophoretic systems, thermosetting gels, prodrugs, and liposomes. Many drugs have been formulated in transdermal systems, and others are being examined for the feasibility of their delivery in this manner (e.g., nicotine antihistamines, beta-blockers, calcium channel blockers, non-steroidal anti-inflammatory drugs, contraceptives, anti-arrhythmic drugs, insulin, antivirals, hormones, alpha-interferon, and cancer chemotherapeutic agents). Research also continues on various chemical penetration enhancers that may allow delivery of therapeutic substances. For example, penetration enhancers such as Azone may allow delivery of larger-sized molecules such as proteins and polypeptides.
经皮给药系统已经存在很长时间了。过去，最常用的系统是用于皮肤病的局部应用乳膏和软膏。其中一些制剂出现全身副作用表明药物可通过皮肤吸收。许多药物已被应用于皮肤进行全身治疗。从广义上讲，经皮给药系统包括所有旨在将活性成分输送到体循环中的局部给药药物制剂。经皮治疗系统的设计目的是通过皮肤向体循环提供药物的可控持续输送。皮肤的相对不渗透性是众所周知的，这与其作为抵御微生物入侵和防止水分等生理必需物质流失的双重保护屏障的功能有关。对导致这种不渗透性的因素的阐明使得将皮肤用作可控全身药物输送途径成为可能。基本上，有四种系统可实现药物有效透过皮肤吸收。微密封系统是一种分区控制的给药系统，它包含一个药物储库，其中药物在与水混溶的溶剂中的饱和悬浮液均匀分散在硅酮弹性体基质中。第二种系统是基质扩散控制型系统。经皮给药的第三种也是使用最广泛的系统是膜渗透控制型系统。最近出现的第四种系统是梯度电荷系统。此外，先进的经皮载体包括离子电渗和超声电渗系统、热固性凝胶、前体药物和脂质体等系统。许多药物已制成经皮给药系统制剂，其他药物也正在研究以这种方式给药的可行性（例如尼古丁、抗组胺药、β受体阻滞剂、钙通道阻滞剂、非甾体抗炎药、避孕药、抗心律失常药、胰岛素、抗病毒药、激素、α干扰素和癌症化疗药物）。关于各种可能允许治疗物质输送的化学渗透促进剂的研究也在继续。例如，氮酮等渗透促进剂可能允许蛋白质和多肽等较大分子的输送。
