WARF: P07314US

Coatings That Inhibit Crystallization of Amorphous Drugs to Improve Stability


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.
OVERVIEWMany 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 INVENTIONUW-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
  • 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 DEVELOPMENTThis coating was successfully used to stabilize indomethacin, an anti-inflammatory drug, and nifedipine, a calcium channel blocker.
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.
Contact Information
For current licensing status, please contact Rafael Diaz at or 608-960-9847.
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A Single Location to Accelerate Translational Development of New Drugs

UW–Madison has the integrative capabilities to complete many key components of the drug development cycle, from discovery through clinical trials. As one of the top research universities in the world, and one of the two best-funded universities for research in the country, UW–Madison offers state-of-the-art facilities unmatched by most public universities.

These include the Small Molecule Screening Facility at the UW Comprehensive Cancer Center; the Zeeh Pharmaceutical Experiment Station, which provides consulting and laboratory services for developing formulations and studying solubility, stability and more; the Waisman Clinical Biomanufacturing Facility; the Wisconsin Institute for Medical Research, which provides UW–Madison with a complete translational research facility; and the innovative, interdisciplinary Wisconsin Institutes for Discovery, home to the private, nonprofit Morgridge Institute for Research and its public twin, WID, part of the university's graduate school. The highly qualified experts at these facilities are ready to work with you to create a library of candidates for drug development.