Potential of imaging analysis in establishing skin concentration-distance profiles for topically applied FITC-dextran 4 kDa

Abstract

Quantitatively determining the skin concentration-distance profiles of topically applied drugs is important for evaluating their safety and efficacy. The aim of the present study was to quantitatively visualize the distribution of hydrophilic drugs through the skin using confocal laser scanning microscopy (CLSM) in order to obtain skin concentration-distance profiles. FITC-dextran with a molecular weight of approximately 4 kDa (FD-4) was selected as the model fluorescent drug in the present study, and excised pig ear skin was used. The skin concentration of FD-4 at each depth of a skin section was assessed by imaging analysis of the intensity of fluorescence. The FD-4 skin concentration-distance profile obtained was analyzed usingFick's second law of diffusion, and was markedly similar to that using skin permeation parameters in the skin permeation study. These results suggest that the present CLSM method may be a promising tool for quantitatively visualizing the concentration-distance profiles of drugs through the skin.

A useful technique using imaging mass spectrometry for detecting the skin distribution of topically applied lidocaine

“…In our previous study (Kijima et al, 2015), drug concentration-depth profiles obtained 13 from imaging analysis by confocal laser-scanning microscopy at non-steady-state and 14 steady-state conditions corresponded fairly well with those obtained from the skin 15 permeation experiments. The measurement by laser-scanning microscopy was 16 conducted without a pretreatment procedure.…”