Table II.

Bidirectional Permeability Data in Buffer and Plasma for Passively Permeating Compounds. Data Represent the Mean ± SD for n = 3 Flux Profiles Per Experiment

Compound (fu in plasma)a	Assay media	Mass balance (%)		Papp (10−6 cm/s)		Efflux ratio
		A-B	B-A	A-B	B-A
14C-Mannitol (0.83)	Buffer	99 ± 2.3	99 ± 1.7	0.29 ± 0.051	0.56 ± 0.026	1.9 ± 0.35
	Plasma	96 ± 4.0	97 ± 5.2	0.31 ± 0.081	0.43 ± 0.021b	1.4 ± 0.37
Propranolol (0.25)	Buffer	85 ± 7.8	97 ± 0.58	58 ± 4.5	52 ± 4.0	0.9 ± 0.10
	Plasma	97 ± 4.6	99 ± 2.3	120 ± 35b	110 ± 19b	0.9 ± 0.31

^af_u values determined at a similar concentration compared to that used for the Caco-2 experiment

^bvalue in plasma was statistically different to the corresponding value in buffer (α = 0.05)