Micelle-Mediated Transport of Vitamin K₁ through Porous Membranes : Contribution of Phosphatidylcholine-Bile Salt Mixed Micelles

Abstract

Diffusion of vitamin K₁ solubilized by phosphatidylcholine-sodium deoxycholate mixed micelles through porous membranes having various pore characterisitcs was examined. The membranes include Nuclepore, Duragard and nitrocellulose membranes, which were intended to mimic the narrow channels in the vicinity of absorptive brush border. The diffusino coefficient of the mixed micelles was 4.6-5.5×10^-7 cm²/s, from which the hydrodynamic radius was calculated to be about 50Å. The dependence of the diffusivity on pore size showed that the transport of the micelles is hindered by pores having a radus ratio of the diffusate to the pore of about 0.05 or larger.