Evaluation of Milk Fat-Globule Membrane (MFGM) Emulsion for Oral Administration: Absorption of α-Linolenic Acid in Rats and the Effect of Emulsion Droplet Size

Abstract

The performance of milk fat-globule membrane (MFGM) emulsion as an oral dosage form was evaluated in rats using [14C] α-linolenic acid as a lipophilic model solute. For emulsions prepared by homogenization alone, the area under the plasma concentration versus time curve (AUC) after oral administration tended to be larger for MFGM emulsion, 35.0 ± 2.5 μg eq • h/ml (mean±S.E., n = 3), than for Tween 80 emulsion, 28.5 ± 0.6 μg eq • h/ml at p<0.1, though the peak plasma concentration (Cmax) and the time required to reach Cmax (Tmax) were not significantly different. The absorption in the intestinal loop was not significantly different between the two emulsions, either. Thus, MFGM emulsion, compared with Tween 80 emulsion, did not show an obvious advantage or enhancement in the oral and intestinal absorption of α-linolenic acid, except for a slight increase in AUC. However, MFGM could be a good alternative to a synthetic emulsifier for oral use, considering that it is of natural origin and may be safer. In addition, it was shown that the AUC, as well as the absorption in the intestinal loop, was decreased for a MFGM emulsion in which the droplet size was reduced by sonication, presumably because of the observed decrease in α-linolenic acid concentration in the water phase, which was assumed to be the result of an increased distribution of α-linolenic acid, due to its amphipathic nature, to the increased oil-water interface. © 1994, The Pharmaceutical Society of Japan. All rights reserved.