ChemRxiv
These are preliminary reports that have not been peer-reviewed. They should not be regarded as conclusive, guide clinical practice/health-related behavior, or be reported in news media as established information. For more information, please see our FAQs.
CUR Solvatochromicity submitted manuscript with SI.pdf (5.49 MB)
0/0

Ultra-High to Ultra-Low Drug Loaded Micelles: Probing Host-Guest Interactions by Fluorescence Spectroscopy

preprint
submitted on 07.06.2019 and posted on 07.06.2019 by Michael M Lübtow, Henning Marciniak, Alexander Schmiedel, Markus Roos, Christoph Lambert, Robert Luxenhofer
Polymer micelles are an attractive means to solubilize water insoluble compounds such as drugs. Drug loading, formulations stability and control over drug release are crucial factors for drug loaded polymer micelles. The interactions between the polymeric host and the guest molecules are considered critical to control these factors but typically barely understood. Here, we compare two isomeric polymer micelles, one of which enables ultra-high curcumin loading exceeding 50 wt.%, while the other only allows a drug loading of only 25 wt.%. In the low capacity micelles, steady-state fluorescence revealed a very unusual feature of curcumin fluorescence, a high energy emission at 510 nm. Time-resolved fluorescence upconversion showed that the fluorescence life time of the corresponding species is too short in the high-capacity micelles, preventing an observable emission in steady-state. Therefore, contrary to common perception, stronger interactions between host and guest can be detrimental to the drug loading in polymer micelles.

Funding

Deutsche Forschungsgemeinschaft

Evonik Foundation

Bavarian Ministry of Education, Culture, Research, and the Fine Arts.

History

Email Address of Submitting Author

robert.luxenhofer@uni-wuerzburg.de

Institution

University of Würzburg

Country

Germany

ORCID For Submitting Author

0000-0001-5567-7404

Declaration of Conflict of Interest

M.M.L. and R.L are listed as inventors on a patent application pertinent to materials discussed in this contribution.

Version Notes

first manuscript version submitted for peer review

Exports