Table 1.

The permeability level of morphine and sucrose via MDCK II cells and MDR-PGP cells.

		Permeability (×106 cm/s)
Substance (concentration)	MDCK II cells	MDR-PGP cells	Mean differences, R2, P value, N
Morphine	27.86 ± 1.22	18.67 ± 0.11	9.1, R2 = 0.98, P=0.0008, N=4
Sucrose (8,000,000 DPM/ml)	0.46 ± 0.09	0.38 ± 0.04	0.08, R2 = 0.26, P>0.01, N=4