Characterization of Caco-2 cell monolayer drug transport properties by cassette dosing using UV/fluorescence HPLC.

Cassette dosing is commonly used in pharmacokinetic studies to decrease time, labor and expenditures. Cassette dosing (having several compounds in a mixture) has been used to screen in vitro permeabilities in Caco-2 cell monolayers. The cassette dosing method has accelerated both transport experiments and sample analyses, which are both part of Caco-2 permeability screening. In this study, a cassette dosing method was used for a mixture of heterogeneous test drugs, which are transported by various mechanisms across the Caco-2 cell monolayer. To characterize the Caco-2 cell monolayer absorption properties, we developed a new UV/fluorescence HPLC method for nine heterogeneous drugs. This new analytical method is fast and specific for high throughput analysis. Fluorescence detection was used to analyze the low concentration of drugs while UV detection was suitable for higher concentrations. The permeability results of single drugs and the mixture of drugs showed a high degree of similarity for each individual compound. All drugs can be applied to the Caco-2 cell culture as a mixture, and the cassette dosing method is suitable for permeability studies.