Thermoreversible supramolecular hydrogels are formed through the self-assembly of small molecules and are generally easily degraded, making them suitable for biomedical applications such as drug delivery. Many successful reports of supramolecular gels in drug delivery have involved a positively charged surfactant and a negatively charged drug. This results in a beneficial slow and sustained release of the drug. However, many dermatological diseases require the delivery of drugs that are not negatively charged.
Lluïsa Pérez-García, Universitat de Barcelona, Spain, and colleagues have used a cationic bis-imidazolium-based amphiphile as a low-molecular-weight gelator (LMWG, pictured) to form gels in the presence of neutral or cationic drugs. It was demonstrated that the drugs could successfully be released from the gel. Commercial products used for the treatment of rosacea (Mirvaso®, Positon®, and Celecrem®) were also tested for comparison. The developed hydrogels could overcome the skin barrier, entering the skin four times faster than the commercial formulations, allowing a high level of drug release.
Effective drug delivery using cationic supramolecular gels could be associated with intermolecular reactions as well as the lack of coulombic attraction between the gelator and the drug. A rabbit model was developed based on the decrease of erythema (redness of the skin) after inducing vasodilation (widening of blood vessels), and in vivo experiments demonstrated the efficacy of the hydrogels. This, combined with the straightforward preparation of thermoreversible supramolecular hydrogels at room temperature, provides an option for industrial-scale production of dermatological formulations to treat rosacea and other chronic skin diseases.
- Cationic Supramolecular Hydrogels for Overcoming the Skin Barrier in Drug Delivery,
David Limón, Claire Jiménez-Newman, Mafalda Rodrigues, Arántzazu González-Campo, David B. Amabilino, Ana C. Calpena, Lluïsa Pérez-García,