Organic Cation Transporters in the blood–air Barrier: Expression and Implications for Pulmonary Drug Delivery

Abstract

Studies concerning the impact that hepatic, renal and intestinal transporters have on drug disposition have been frequently reported in the literature. Surprisingly, however, little is known regarding the distribution and function of drug-transporter proteins of the lung epithelium. Many drugs (delivered to the lung) have a net positive charge and, thus, are potential substrates of organic cation transporters; currently marketed compounds (e.g., ronchodilators), as well as novel drug candidates in development, are such substrates. It is the aim of this review to summarize the current state of organic cation-transporter expression analysis in the lung and in in vitro models of bronchial and alveolar barriers. Moreover, activity of selected transporters in lung epithelium in situ and in vitro will be highlighted, and their potential role in pulmonary drug disposition will be addressed. One example included here is the transporter-dependent absorption of β₂-agonists in respiratory epithelial cells.

Financial & competing interests disclosure

This work has been funded by a Strategic Research Cluster grant (07/SRC/B1154) under the National Development Plan co-funded by EU Structural Funds and SFI. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.