US EPA

3045434 

Journal Article 

Effect of frozen human epidermis storage duration and cryoprotectant on barrier function using two model compounds 

Barbero, AM; Frasch, HF 

2016 

Yes 

Skin Pharmacology and Physiology
ISSN: 1660-5527
EISSN: 1660-5535 

S. Karger AG 

29 

1 

31-40 

English 

26606593 

10.1159/000441038 

WOS:000370153200006 

Skin is commonly stored frozen and then thawed prior to use for in vitro permeation experiments. Does frozen storage of skin alter its barrier property? Numerous studies have found contradictory answers to this question. In this study, the steady-state flux and lag time of diethyl phthalate (DEP) were measured for fresh human skin and skin frozen at -85°C for 1, 2, 3, 6, 9, 12, and 18 months with 10% glycerol as a cryoprotective agent. No significant differences in steady-state flux were found between fresh and previously frozen samples (p = 0.6). For lag time, a significant (p = 0.002) difference was found among all groups, but comparisons with fresh skin were not significant. Does glycerol have a cryoprotective effect? The steady-state flux and lag time of DEP and caffeine were measured through human skin stored at -85°C for up to 12 months with and without 10% glycerol. No significant differences in steady-state flux or lag time were found between samples stored with or without glycerol for either DEP or caffeine (p ≥ 0.17). These findings support the use of frozen skin to measure the passive permeation of chemicals in studies unconcerned with viability and metabolism. Published by S. Karger AG, Basel. 

Percutaneous penetration; Skin absorption; Human skin; Freezing; Storage conditions; Skin barrier function; Steady-state flux; Lag time; Diethyl phthalate; Caffeine