Table 1. The apparent permeability (P _app) of enkephalin and glycosylated enkephalins, assessed using in vitro Caco-2 cell monolayer experiments (n = 3).

	P app (×10−7 cm/s)
Compound	Control (compound only)	Phlorizin	Phloretin
Enkephalin	0.31±0.11	0.19±0.19	0.74±0.40
Gal-Enk	7.98±2.03	11.80±2.76	15.80±7.23
Lac-Enk	17.20±12.40	7.11±1.45	9.21±0.84
Gal-Lac-Enk	4.40±1.63	5.61±1.37	7.12±1.37