Widdicombe J
Sherrington School of Physiology, St. Thomas' Campus (UMDS), London, U.K.
Indian J Physiol Pharmacol. 1998 Jan;42(1):3-14.
This paper reviews the mechanisms and physiological processes that act when drugs or chemicals are administered into the lower airways and lungs. Administration is usually by aerosol. Agents can be given, for example, either to treat pulmonary diseases such as asthma, or the test for airways' responsiveness or other functions, or as a means of access of a drug to the systemic circulation. The first barrier to absorption is the airway surface liquid, including mucus. The thickness of this layer will determine the concentration of the drug in solution, and therefore its rate of entry into the tissue. The agent must then penetrate the airway epithelium, the strongest barrier for hydrophilic agents. Agents must then diffuse through the epithelial basement membrane and the interstitium. Finally, the agent may be taken up into the mucosal vasculature, and changes in blood flow will influence its uptake and distribution. If the drug is to reach a target organ, such as airway smooth muscle or glands, these barriers have first to be traversed.
本文综述了药物或化学物质经气道下段和肺部给药时所涉及的作用机制和生理过程。给药通常采用气雾剂形式。例如，给药的目的可以是治疗诸如哮喘之类的肺部疾病，或检测气道反应性或其他功能，或作为药物进入体循环的一种途径。吸收的第一道屏障是气道表面液体，包括黏液。这一层的厚度将决定溶液中药物的浓度，进而决定其进入组织的速率。然后，药物必须穿透气道上皮，这是亲水性药物最强的屏障。接着，药物必须扩散穿过上皮基底膜和间质。最后，药物可能会被吸收进入黏膜血管，血流的变化将影响其吸收和分布。如果药物要到达靶器官，如气道平滑肌或腺体，就必须首先穿过这些屏障。
