Developing a method for the study of perfusion effects in topical product pharmacokinetics

Area of Science:

• Pharmacology
• Dermatology
• Biophysics

Background:

• Topical drug delivery faces challenges due to skin's complex barrier.
• Existing pharmacokinetic assessment methods are often limited to ex vivo analysis.
• In vivo perfusion significantly influences topical drug uptake and disposition.

Purpose of the Study:

• To develop and validate a novel in vivo method for assessing perfusion effects on topical drug uptake.
• To quantify the impact of dermal perfusion on tazarotene pharmacokinetics in mouse skin.
• To compare drug permeation in lipid-rich versus lipid-poor skin regions under perfused and non-perfused conditions.

Main Methods:

• Utilized stimulated Raman scattering (SRS) microscopy for chemically-specific, time-resolved imaging of topical drug permeation.
• Employed a paired mouse ear skin model, comparing in vivo (perfused) and ex vivo (non-perfused) conditions.
• Quantified tazarotene concentration and pharmacokinetic parameters (Tmax, Cmax, AUC) in stratum corneum and sebaceous glands.

Main Results:

• Significant differences in tazarotene concentration-time profiles and pharmacokinetic parameters were observed between in vivo and ex vivo conditions.
• Perfusion (in vivo) led to increased tazarotene permeation and elimination compared to non-perfused (ex vivo) skin.
• Variations in uptake were noted between lipid-rich and lipid-poor regions, influenced by perfusion status.

Conclusions:

• The developed SRS microscopy method effectively assesses in vivo perfusion effects on topical drug uptake.
• Dermal perfusion is a critical factor influencing topical drug disposition and efficacy.
• Understanding perfusion's role enhances the development of effective topical drug delivery systems.