Validation of reflectance infrared spectroscopy as a quantitative method to measure percutaneous absorption in vivo.
Attenuated total-reflectance infrared (ATR-IR) spectroscopy has been used to follow the penetration of a model compound (4-cyanophenol; CP) across human stratum corneum (SC) in vivo, in man. CP was administered for periods of 1, 2, or 3 hr, either (a) as a 10% (w/v) solution in propylene glycol or (b) in an identical vehicle which also contained 5% (v/v) oleic (cis-9-octadecenoic) acid. At the end of the treatment periods, SC at the application site was progressively removed by adhesive tape-stripping. Prior to the removal of the first tape-strip, and after each subsequent tape-strip, an ATR-IR spectrum of the treated site was recorded. The presence of CP, as a function of position in the SC, was monitored spectroscopically via the intense C = N stretching absorbance at 2230 cm-1. The absolute amount of CP, as a function of SC depth, was determined by "spiking" the applied solutions with 14C-labeled compound and subsequent liquid scintillation counting of the removed tape-strips. The presence of oleic acid in the applied formulation significantly increased the rate and extent of CP delivery as evaluated by either spectroscopy or radiochemical analysis. Furthermore, the ATR-IR and direct 14C analysis of CP as a function of SC position were highly correlated. These data strongly support, therefore, the validation of ATR-IR as a quantitative tool to assess percutaneous penetration in vivo.
Higo
N
N
Department of Pharmacy, University of California, San Francisco 94143-0446.
Naik
A
A
Bommannan
D B
DB
Potts
R O
RO
Guy
R H
RH
D000279:Administration, Cutaneous; D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008996:Monoamine Oxidase Inhibitors / Q000493:pharmacokinetics*; D010636:Phenols / Q000008:administration & dosage / Q000493:pharmacokinetics*; D012869:Skin Absorption; D017550:Spectroscopy, Fourier Transform Infrared
D008996:Monoamine Oxidase Inhibitors; D010636:Phenols; C007178:4-cyanophenol