Methods for quantifying intrafollicular drug delivery: a critical appraisal

Area of Science:

• Dermatology and Pharmaceutical Sciences
• Drug Delivery and Formulation

Background:

• Hair follicles are increasingly recognized as key pathways for topical drug absorption and reservoirs.
• Understanding follicular drug penetration is vital for treating skin conditions and for systemic drug delivery.
• Current knowledge of follicular drug transport mechanisms is limited, necessitating new quantification methods.

Purpose of the Study:

• To review and critically assess existing quantitative methodologies for measuring follicular drug penetration and deposition.
• To provide a comprehensive overview of techniques used to study drug interactions with hair follicles and pilosebaceous units.
• To inform future research directions in follicular drug transport.

Main Methods:

• Review of comparative techniques measuring drug flux across follicle-containing and follicle-free skin.
• Analysis of methods including the skin sandwich, differential stripping, and optical imaging.
• Discussion of techniques for assessing drug-sebum interactions.

Main Results:

• The review elucidates the complexities in quantifying drug delivery via follicles and pilosebaceous units.
• Various methodologies offer different advantages and disadvantages for assessing follicular drug transport.
• Expert opinion highlights the need for broader research to identify optimal quantification methods.

Conclusions:

• The field of follicular drug transport quantification remains underdeveloped.
• Larger-scale studies employing multiple techniques and drugs are essential for advancing understanding.
• Further research is required to establish the most effective methods for quantifying follicular drug penetration.