d‑Amino Acids Boost the Selectivity and Confer Supramolecular Hydrogels of a Nonsteroidal Anti-Inflammatory Drug (NSAID)

As systemically used therapeutics for treating acute or chronic pains or inflammations, nonsteroidal anti-inflammatory drugs (NSAIDs) also associate with the adverse gastrointestinal and renal effects and cardiovascular risks. Thus, it is beneficial to develop topical gels that selectively inhibit cyclooxygenase-2 (COX-2) for the management of local inflammation. In this work, we demonstrate that the covalent conjugation of d-amino acids to naproxen (i.e., a NSAID) not only affords supramolecular hydrogelators for the topical gels but also unexpectedly and significantly elevates the selectivity toward COX-2 about 20× at little expense of the activity of naproxen. This work illustrates a previously unexplored approach that employs d-amino acids for the development of functional molecules that have dual or multiple roles and exceptional biostability, which offers a new class of molecular hydrogels of therapeutic agents.