also noted that glycolic and lactic acid, which are polar
chemicals, are strongly retained in skin in vitro after a 24-h study.
Lipophilic compounds may be retained in skin artificially in in vitro
studies because of difficulty in partitioning from lipid areas in the skin
into aqueous receptor fluids. The pyrethroids examined in the present
study are lipophilic with measured Log Ps ranging from 4.5 to 6.4.