Instrumented In Vitro Approaches to Assess Epithelial Permeability of Drugs from Pharmaceutical Formulations

The following chapter gives an overview of instrumented approaches to investigate the interactions of orally or pulmonary administered formulations with epithelial cell cultures in vitro. The first section is focused on the combined assessment of drug release/dissolution and subsequent absorption/permeation for solid oral dosage forms. Experimental approaches to mimic the complex physiologically surroundings in the gastrointestinal tract are presented as well as combinations of dissolution and permeation apparatus. The second part describes different experimental approaches to simultaneously assess deposition and subsequent absorption of pharmaceutical aerosol formulations, typically by adapting some existing impactor/impinger devices to accommodate pulmonary epithelial cell culture systems. Differences between longtime and low-dose aerosol deposition in environmental toxicology and short time bolus inhalation of pharmaceutical aerosols are elucidated.