Silymarin PlantCrystals for Improved Dermal Drug Delivery

Area of Science:

• Dermal drug delivery
• Nanotechnology in cosmetics and pharmaceuticals
• Plant-derived materials science

Background:

• PlantCrystals (PCs) are submicron plant-derived particles produced via milling or homogenization.
• Previous research suggests PCs improve dermal delivery of lipophilic active ingredients (APIs) potentially via extracellular vesicle (EV) formation.
• The study investigates PC suitability for enhancing dermal penetration of various API types.

Purpose of the Study:

• To evaluate PlantCrystals for enhancing dermal penetration of hydrophilic, lipophilic, and poorly soluble APIs.
• To compare PC formulation efficacy against simple solutions, classical EVs, and post-preparation API addition.
• To assess the skin hydrating properties of PC formulations.

Main Methods:

• Milk thistle seeds were milled to produce Silymarin-PCs.
• Hydrophilic, lipophilic, and poorly soluble API surrogates were loaded into PCs.
• Dermal penetration and skin hydration were assessed using an ex vivo porcine ear model.
• PCs were characterized by size, size distribution, and zeta potential.

Main Results:

• Milling produced submicron PCs (approx. 300 nm); loaded PCs were slightly larger.
• PCs significantly enhanced dermal penetration, particularly for lipophilic APIs (+90%).
• EV formation during PC production aids API encapsulation, most effective for lipophilic compounds.
• All formulations improved skin hydration by 30-40%.

Conclusions:

• Milk thistle seeds are a suitable source for PC production.
• PCs effectively enhance skin hydration and dermal penetration of lipophilic and poorly soluble APIs.
• PCs demonstrate limited enhancement for hydrophilic APIs' dermal penetration.