Permeation of dipeptides and phosphono dipeptides through liquid emulsion membranes; stereoselectivity of the process

Abstract

Dipeptides and their analogues are readily transported through liquid emulsion membranes. They rapidly permeate the membrane during the first ten minutes of the process and then the permeation velocity achieves a constant value. The permeation rate strongly depends on the concentration of Rokwin 60, a commercially available optically active surfactant used to stabilize the emulsion, while the influence of macrocyclic carriers on the transport efficiency was less significant. A membrane composed of 8% w/w Rokwin 60 solution in carbon tetrachloride showed marked chiral discrimination, i.e. LD-dipeptides were transported faster than their LL-counterparts. The degree of stereoselectivity of the permeation process varied from 2.13 to 1.10 depending on both the peptides structure and the permeation time.