A. Collett et al., COMPARISON OF HT29-18-C-1 AND CACO-2 CELL-LINES AS MODELS FOR STUDYING INTESTINAL PARACELLULAR DRUG ABSORPTION, Pharmaceutical research, 13(2), 1996, pp. 216-221
Purpose. To compare the permeability characteristics of HT29-18-C-1 co
lonic epithelial cell line with Caco-2, an established model of intest
inal drug transport. Methods, Cell lines were grown as epithelial mono
layers. Permeability was measured over a range of transepithelial elec
trical resistance (R(t)) using a group of drug compounds. Results, HT2
9-18-C-1 develop R(t) slowly when grown in culture, allowing permeabil
ity to be measured over a wide range (80-600 Omega . cm(2)). In contra
st, Caco-2 monolayers rapidly develop R(t) of approximate to 300 Omega
. cm(2) and require Ca2+-chelation to generate R(t) equivalent to hum
an intestine (60-120 Omega . cm(2)). Permeability of atenolol, ranitid
ine, cimetidine, hydrochlorothiazide and mannitol across HT29-18-C-1 d
ecreased 4-5 fold as R(t) developed from 100-300 Omega(2) . cm(2) indi
cating they permeate via the paracellular route. In contrast, ondanset
ron showed no difference in permeability with changing R(t) consistent
with transcellular permeation. Permeability profiles across low R(t)
HT29-18C(1) and pulse EGTA-treated Caco-2 monolayers were the same for
all 5 paracellular drugs suggesting that transient Ca2+ removal does
not alter selectivity of the tight junctions. Permeabilities of cimeti
dine, hydrochlorothiazide and atenolol across 100 Omega . cm(2) HT29-1
8-C-1 monolayers reflect more closely those reported for the human ile
um in vivo than did mature Caco-2 monolayers. Conclusions. HT29-18-C-1
monolayers can be used to study drug permeability at R(t) values simi
lar to human intestine without the need for Ca2+ chelation. As such, t
hey offer a useful alternative to Caco-2 for modelling intestinal drug
absorption.