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Dynamic in-situ eutectic formation for topical drug delivery.
Sarah Fiala1, Marc B Brown, Stuart A Jones
1Institute of Pharmaceutical Science, King's College London, London, UK.
The Journal of Pharmacy and Pharmacology
|October 13, 2011
Summary
Molten eutectic mixtures, formed in situ without delivery vehicles, showed that drug presentation rate, not melting point, drives transmembrane transport. Lidocaine-rich mixtures enhanced molecule delivery most effectively.
Area of Science:
- Pharmaceutical Sciences
- Physical Chemistry
- Drug Delivery Systems
Background:
- Transmembrane transport of eutectic systems is complex due to vehicle-induced penetration enhancement.
- Understanding solution-state properties is crucial for predicting drug delivery.
- Eutectic mixtures offer potential for enhanced drug solubility and delivery.
Purpose of the Study:
- To investigate the solution-state properties of eutectic systems relevant to transmembrane transport.
- To determine transport characteristics in the absence of delivery vehicles.
- To elucidate the relationship between eutectic composition and drug permeation.
Main Methods:
- In-situ formation of molten lidocaine-prilocaine eutectics using a hydrofluoroalkane (HFA) propellant.
- Assessment of transmembrane transport through silicone membranes and human skin using Franz diffusion cells.
- Comparison with in-house manufactured creams as controls.
Main Results:
- HFA spray enabled molten eutectic formation even above the mixture's melting point.
- Lidocaine-rich mixtures (0.7% w/w lidocaine:prilocaine) demonstrated the most effective molecule presentation (1985.06 ± 128.87 µg/h/cm²).
- No correlation was observed between melting point and transmembrane transport.
Conclusions:
- Melting point is not a determinant of transmembrane transport for lidocaine:prilocaine eutectics.
- Drug presentation rate to the membrane interface is the primary driver of transport.
- High-activity, drug-rich molten eutectics maximize transmembrane transport efficiency.
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