2.2.1. Human skin. Freshly excised, healthy human upper breast skin
was obtained via Caltag Medsystems Ltd. (Buckingham, UK) from
three consented female adults (aged 35, 37 and 34 years) following
plastic surgery. Selection criteria included: Caucasian, no stretchmarks,
no scars, no hair and full thickness skin without adipose tissue. Skin
was kept on ice for no longer than 4 h prior to the onset of the ex vivo
skin absorption studies. Upon receipt, the ex vivo skin samples were
equilibrated for 1 h with 3 mL of DMEM (Dulbecco's Modied Eagle's
Medium)-based (Sigma-Aldrich, UK) culture medium (Table SI-1) at
5% CO2 and 37 °C before use in permeation experiments.