Infrared densitometry: a fast and non-destructive method for exact stratum corneum depth calculation for in vitro tape-stripping.
The investigation of drug penetration into the stratum corneum (SC) by tape-stripping requires an accurate measure of the amount of SC on each tape-strip in order to determine the depth inside the SC. This study applies infrared densitometry (IR-D) to in vitro tape-stripping using the novel Squame Scan(R) 850A. The device had recently been shown to provide accurate measurements of the SC depth for tape-stripping in vivo. Furthermore, the suitability of IR-D for determining the endpoint of tape-stripping, i.e. complete SC removal, was tested. The SC depth was computed from the IR-D data of sequential tape-strips and compared to the results of a protein assay as gold standard. IR-D provided accurate depth results both for freshly excised skin and for skin stored frozen for up to 3 months. In addition, the lower limit of quantification of IR-D indicates the complete removal of the SC (less than 5% of the total SC remaining) and can be used for adjusting the number of tapes applied in situ. Therefore, IR-D is an accurate, fast and non-destructive method for SC depth determination.
Hahn
T
T
Department of Biopharmaceutics and Pharmaceutical Technology, Saarland University, Saarbrücken, Germany.
Hansen
S
S
Neumann
D
D
Kostka
K-H
KH
Lehr
C-M
CM
Muys
L
L
Schaefer
U F
UF
D000268:Adhesiveness; D000328:Adult; D003720:Densitometry / Q000379:methods* / Q000592:standards; D000078404:Epidermal Cells; D004817:Epidermis / Q000502:physiology*; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D012869:Skin Absorption / Q000502:physiology; D013055:Spectrophotometry, Infrared / Q000379:methods* / Q000592:standards; D053832:Surgical Tape / Q000592:standards; D013997:Time Factors; D014870:Water Loss, Insensible / Q000502:physiology; D055815:Young Adult