Division of Pharmaceutics, College of Pharmacy, University of Texas at Austin, Austin, TX, USA.
Int J Pharm. 2011 Mar 15;406(1-2):1-10. doi: 10.1016/j.ijpharm.2010.12.040. Epub 2011 Jan 11.
The understanding of deposition of particles in the respiratory tract is of great value to risk assessment of inhalation toxicology and to improve efficiency in drug delivery of inhalation therapies. There are three main basic mechanisms of particle deposition based primarily on particle size: inertial impaction, sedimentation and diffusion. The regional deposition in the lungs can be evaluated in regards to the aerodynamic particle size, in which particle density plays a significant role. In this review paper, we first introduce the available imaging techniques to confirm regional deposition of particles in the human respiratory tract, such as planar scintigraphy, single photon emission computed tomography (SPECT) and positron emission tomography (PET). These technologies have widely advanced and consequently benefited the understanding of deposition pattern, although there is a lack of lung dosimetry techniques to evaluate the deposition of nanoparticles. Subsequently, we present a comprehensive review summarizing the evidence available in the literature that confirms the deposition of smaller particles in the smaller airways as opposed to the larger airways.
颗粒在呼吸道中的沉积机制对于吸入毒理学的风险评估以及提高吸入疗法的药物输送效率具有重要意义。基于颗粒大小，主要有三种基本的颗粒沉积机制：惯性冲击、沉降和扩散。肺部的区域性沉积可以根据空气动力学粒径进行评估，其中颗粒密度起着重要作用。在这篇综述文章中，我们首先介绍了可用于确认人体呼吸道中颗粒区域性沉积的现有成像技术，例如平面闪烁显像、单光子发射计算机断层扫描（SPECT）和正电子发射断层扫描（PET）。这些技术已经得到了广泛的发展，从而有助于我们理解沉积模式，尽管缺乏用于评估纳米颗粒沉积的肺部剂量测定技术。随后，我们全面回顾了文献中可用的证据，这些证据证实了较小颗粒沉积在较小气道中，而不是较大气道中。
