Ointment formulations of reactive topical skin protectants (rTSPs) or topical skin protectants (TSPs) based on perfluorinated polyether material (PFPE, i.e., fomblin RT-15) were prepared and spin labeled. Four N-oxyl-4-4'-dimethyloxazolidine derivatives of stearic acid, 5-NS, 7-NS, 12-NS, and 16-NS, were used as spin probes. The spin-labeled vehicle, fomblin-RT-15, and vehicle containing chloroamide (S-330, an antivesicant) were exposed to various concentrations of half-mustard gas. The order parameter (S) was dependent on the depth of penetration of the paramagnetic group into the vehicle (fomblin) and on the chemical composition of the reactive antivesicant under investigation. The net change of the viscosity of the vehicle and the chemical composition were seen to affect the penetration profile. This will provide a useful in vitro screening technique to develop antivesicant TSPs.
