Wisconsin Alumni Research Foundation

Drug Delivery
Drug Delivery
Coatings That Inhibit Crystallization of Amorphous Drugs to Improve Stability
WARF: P07314US

Inventors: Lian Yu, Melgardt De Villiers, Tian Wu

The Wisconsin Alumni Research Foundation (WARF) is seeking commercial partners interested in developing a method of coating amorphous drugs to improve their stability and maintain their solubility.
Many drugs that are potentially efficacious for treating diseases, such as cancer, have limited usefulness because they are relatively insoluble. Preparing these drugs in an amorphous, or “glassy,” form improves their solubility and bioavailability.

However, they are less stable in this form.  Most amorphous drugs crystallize over time, negating their advantages.  Typically, amorphous drugs begin crystallizing on the surface, and then the remaining solid reforms into the crystalline form.
The Invention
UW-Madison researchers have developed a method of coating amorphous drugs to inhibit surface crystallization and improve their stability.  An ultra thin polyelectrolyte coating or other biocompatible immobilizing material is applied to the surface of an amorphous solid.  This coating allows amorphous pharmaceuticals to maintain their amorphous state, and therefore their solubility, over extended periods of time. 
  • Stabilizing amorphous drugs
Key Benefits
  • Increases stability of amorphous drugs
  • Allows amorphous drugs to maintain their solubility for longer periods of time
  • Allows for coating to be sufficiently thin so it does not affect the dissolution rate of the coated pharmaceutical
  • May improve the wetting ability, aqueous dispersibility and powder flow of the coated drug
  • Coating is simple, cost-effective and applicable to many amorphous pharmaceuticals.
  • Does not require the use of surfactants or other components that may be poorly tolerated
Stage of Development
This coating was successfully used to stabilize indomethacin, an anti-inflammatory drug, and nifedipine, a calcium channel blocker.
Additional Information
For More Information About the Inventors
  • Wu T., Sun Y., Li N., de Villiers M. and Yu L. 2007. Inhibiting Surface Crystallization of Amorphous Indomethacin by Nanocoating. Langmuir 23, 5148-5153.
  • Zhu L., Wong L. and Yu L. 2008. Surface-Enhanced Crystallization of Amorphous Nifedipine. Mol. Pharm. 5, 921–926.
For current licensing status, please contact Rafael Diaz at [javascript protected email address] or 608-960-9847