Permeability Characteristics of Calu-3 Human Bronchial Epithelial Cells: In Vitro - In Vivo Correlation to Predict Lung Absorption in Rats

Abstract

The goal of this study was to evaluate the permeability characteristics of Calu-3, human bronchial epithelial cells to passive and actively transported drugs and to correlate the data with other in vitro models and rat lung absorption in vivo. Air-interface cultured Calu-3 cells grown on collagen-coated permeable filter supports formed "tight" polarized and well differentiated cell monolayers with apical microvilli and tight-junctional complexes. Within 8-10 days, cell monolayers developed trans-epithelial electrical resistance (TEER) > 1000 ohm cm2 and potential difference about 11-16 mV. Solute permeability was dependent on lipophilicity, and inversely related to molecular size. Calu-3 cells actively transported amino acids, nucleosides and dipeptide analogs, but not organic anions, organic cations or efflux pump substrates. The permeability characteristics of Calu-3 cells correlated well with primary cultured rabbit tracheal epithelial cells in vitro (r2 = 0.91), and the rate of drug absorption from the rat lung in vivo (r2 = 0.94). The absorption predicted from the regression equation correlated well with observed values. In conclusion, in vitro-in vivo correlation studies indicate that the Calu-3 cell culture model is a potentially useful model to predict absorption of inhalation delivery drug candidates.

In Vitro Testing for Orally Inhaled Products: Developments in Science-Based Regulatory Approaches

“…The absorption of drugs from the lungs to the systemic circulation is generally rapid, with high bioavailability for compounds with a wide range of physicochemical properties (42,43). Despite interest in lung transporters (44,45), passive diffusion appears to be the dominant mechanism.…”

“…Cell culture models of the epithelium, the principal respiratory absorption barrier, are typically used to characterize drug permeability (47). Although alternative cell lines are being developed, most studies utilize the cell types for which in vitro-in vivo relationships have been reported, namely, 16HBE14o-(48), Calu-3 cell lines (42), and primary alveolar cell cultures (49). The isolated perfused lung is an ex vivo technique which has been used to evaluate permeability in the intact lung and has been correlated with permeability in cell cultures and in vivo (50)(51)(52).…”

Non-animal models of epithelial barriers (skin, intestine and lung) in research, industrial applications and regulatory toxicology

“…These include cell lines such as the adenocarcinoma cell line Calu-3 (Shen et al, 1994) and the SV-40 transformed cell line 16HBE 14o- (Cozens et al, 1994), both of which are able to form tight junctions and polarize when grown on semi-permeable filter supports (e.g., Transwell ® inserts). The barrier properties of these cell lines have been described Forbes et al, 2003;Mathias et al, 2002) and detailed protocols for their culture, maintenance, growth and permeability assessment have been published (Meaney et al, 2002), but it should be noted that culture methods vary between laboratories, e.g., passage number, seeding density, submerged or air-liquid interface, use of extracellular matrices, media composition, duration of culture -see Forbes and Ehrhardt (2005).…”

Does concentration influence viability of the bronchial epithelial cell line chronically exposed to antiasthmatic drugs?

“…As for research on respiratory epithelial permeability to drugs, a correlation between the in vitro model and in vivo conditions was observed [25]. However, the correlation between in vitro model and in vivo conditions in the cytotoxicity studies is significantly less obvious.…”