A diffusion chamber compatible with Millicell® culture supports has been developed for the measurement of permeability coefficients across caco-2 cell monolayers, these monolayers themselves having been demonstrated to be a valuable in vitro model of intestinal drug absorption. Attributes of the chamber include its unibody design of clear polycarbonate (Lexan®), temperature control by water bath submersion and fluid agitation by magnetically driven stir bars. Characterization of the apparatus with respect to control of unstirred water layer (UWL) thickness was accomplished by studying, as a function of stirring rate, both the dissolution rate of p-aminobenzoic acid and testosterone flux across caco-2 cell monolayers. These studies indicated that the design was capable of reducing UWL thickness by as much as 90% in the case of testosterone flux and converting the rate limiting step in flux of this steroid from the UWL to the caco-2 barrier. Importantly, based on the consistency in the flux of mannitol across the range of stirring rates applied, as well as the low permeability of this leakage marker across the, caco-2 monolayers compared to testosterone (< 0.5% of testosterone permeability), stirring did not adversely affect the barrier integrity of the monolayers.
- Drug absorption
- Intestinal permeability models
- MilliceIl® cell culture supports
- Unstirredwater layer
ASJC Scopus subject areas
- Pharmaceutical Science