We determined the bioavailability of vitamin E from self-assembly structures in patients with diagnosed chronic pancreas insufficiency. Vitamin E solubilized in dispersed inverted bicontinuous cubic phase and in micellar formulation was delivered directly to the small intestine by tube-feeding. A cross-over study with randomization of 6 subjects and 2 treatments including a combined dose of 18 mg (27 IU) of vitamin E (RRR-[5,7-methyl-(H-2(6))]a-tocopherol) and 27 mg (27 IU) vitamin E acetate (RRR-[5-methyl-H-2(3)]-alpha-tocopheryl acetate) was applied over a time period of 1 h. Plasma samples were collected for 56 h and analyzed by liquid chromatography mass spectrometry. Appearance of labeled tocopherols originating from the treatment started at 25 h and reached C-max (0.6-4.6 mu M depending on subject) in the 7-9 h window. From the T-max onwards, both forms of tocopherols diminished slowly to 30-50% of their maxima within 56 h. Strong inter-individual variation was observed in the plasma appearance curves (relative standard deviation varied between 38-45%). No significant discrimination was found between the absorption of free or acetylated forms of deuterated a-tocopherol confirming that application of acetylated alpha-tocopherol provides the same bioavailability as free alpha-tocopherol. This observation is valid in both dispersed inverted bicontinuous cubic phase and micellar formulations. Furthermore, since the area-underthe-curve values from cubic phase and from micellar formulations are similar, the cubic phase formulation could represent an alternative delivery system for lipophilic micronutrients in conditions or studies where polysorbatebased micelles cannot be generated.