# Advancements in Therapeutic Deep Eutectic Solvents as Multifunctional Transdermal Delivery Systems

## TL;DR

This paper reviews how Therapeutic Deep Eutectic Solvents (TheDES) can improve drug delivery through the skin by enhancing solubility and permeation.

## Contribution

The paper introduces the novel 'lipid exchange' effect as a mechanism for enhancing drug permeation through the skin.

## Key findings

- TheDES significantly enhance solubility and transdermal flux of APIs.
- TheDES can be formulated into advanced dosage forms like eutectogels and nanoemulsions.
- TheDES show promise in treating pain, infections, and chronic diseases.

## Abstract

The human skin, specifically the stratum corneum (SC), remains a formidable barrier to the delivery of therapeutic agents. Nearly 80% of new drug candidates exhibit poor solubility or low permeability, necessitating the development of novel delivery vehicles. Therapeutic deep eutectic solvents (TheDES) have emerged as a “green,” multifunctional solution capable of significantly enhancing the solubility and transdermal flux of active pharmaceutical ingredients (APIs). This review discusses the physicochemical fundamentals of TheDES, mechanisms of permeation enhancement—including the newly identified “lipid exchange” effect—and the transition from liquid solvents to advanced dosage forms such as eutectogels and nanoemulsions. Current therapeutic applications in pain management, infectious diseases, and chronic conditions are highlighted, alongside critical assessments of dermatological safety and future directions in computational modeling.