The Caco-2 cell line monolayer is widely used as an in vitro model of human intestinal absorption. The reference protocol predicts 21±1 days for the cells to reach an appropriate level of differentiation after seeding on the filters and to create a confluent monolayer, which can then be used for the permeability assay. The disadvantage of the Caco-2 cell line is therefore a very long cultivation time. In the cell laboratory of the Faculty of Pharmacy, with an increasing number of passages, a strain of the Caco-2 cell line appeared, which began to show the properties of accelerated differentiation and rapid integrity development, as a result of which it reaches a properly confluent monolayer much earlier. In our thesis, we evaluated this strain after genotyping by ATCC, which recognized the strain as an authentic Caco-2 cell line; we created a culture protocol, with which we determined how the density of seeding of the cells on the inserts affects the rate of proliferation and the time for integrity development. This was verified by measuring the TEER and by checking the permeability of model compounds. According to this protocol, on the 5th day after planting the cells on the culture filters, a prepared monolayer was obtained for permeability assay and comparison with a monolayer obtained by the reference protocol. Based on the FDA guidelines, we created three groups of model compounds that allowed simultaneous quantification in acceptor solutions, and with them, we evaluated the adequacy of the separation of high (HPM), medium (MPM), and low (LPM) permeable compounds. We compared the obtained results between the reference strain and the tested strain, which demonstrated rapid integrity development, and confirmed that the tested strain quickly reaches a confluent monolayer and is useful for determining permeability; we found that the tested strain, based on the measurement of TEER and permeability of FITC-dextrans, has adequate cell integrity, it has a good ability to differentiate between molecules with high permeability (HPM) of those with medium (MPM) and low (LPM) permeability, and that it shows a good correlation between human absorption in vivo and the permeability of active substances in vitro.
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