Topical & Transdermal Drug Delivery | Skin

MedPharm’s Formulation Strategy

MedPharm’s formulation strategy is applied consistently across all routes of delivery, where excipients and formulation design are selected based on the drug and the target product profile to optimize stability and delivery to the site of action.

Formulations for the Skin

The skin is a complex organ that provides:

Protection from physical, chemical, and biological challenges

Moisture retention

Thermoregulation

Metabolic and immunological functions

Sensory perception

Formulations designed for the skin are optimized to control drug release and delivery. This includes the use of solvents and non-solvents to manage drug thermodynamic activity, along with both passive and active permeation enhancement strategies.

Formulation composition, microstructure, and changes after application, such as evaporation of volatile excipients, can significantly influence drug stability and delivery. These factors are evaluated throughout development.

Topical skin formulations range from:

Single-phase systems such as gels, liquids, and sprays

Multi-phase emulsions such as creams and foams

Patches such as drug in adhesive or in-situ forming films (such as MedSpray)

MedPharm typically selects excipients already approved for the intended route of delivery, such as those listed in the FDA Inactive Ingredient Database. This approach minimizes safety concerns, reduces regulatory risk, and limits the need for extensive in vivo safety studies.

Additional selection factors include:

Excipient concentration
Irritation potential
Dosing requirements
Target population and indication
Intended marketing territories

High-Throughput Flow-Through Diffusion Cells vs Franz Cells

To address limitations of commercially available diffusion cells, MedPharm developed MedFlux-HT®, a proprietary high-throughput flow-through diffusion system for evaluating skin and tissue permeation and penetration.

MedFlux-HT® uses a continuous-flow design with an optimized flow path that enables:

More accurate and detailed flux profiles
Improved sink conditions
Shorter study timelines
Enhanced analysis of lipophilic compounds without receiver-fluid additives

The system is thermostatically controlled to maintain physiological temperature, and receiver-fluid collection is automated to support higher throughput and improved reproducibility.

MedFlux-HT® also uses smaller dosing areas, allowing a greater number of replicates from limited human tissue supplies.