β-Amino Acid and Amino-Alcohol Conjugation of a Nonsteroidal Anti-Inflammatory Drug (NSAID) Imparts Hydrogelation Displaying Remarkable Biostability, Biocompatibility, and Anti-Inflammatory Properties

A well-known nonsteroidal anti-inflammatory drug (NSAID), namely, naproxen (Np), was conjugated with β-alanine and various combinations of amino alcohols and l-alanine. Quite a few bioconjugates, thus synthesized, were capable of gelling pure water, NaCl solution (0.9 wt %), and phosphate-buffered saline (PBS) (pH 7.4). The hydrogels were characterized by rheology and electron microscopy. Hydrogelation was probed by FT-IR and temperature-variable 1H NMR studies. Single-crystal X-ray diffraction (SXRD) of a nonhydrogelator and a hydrogelator in the series established a useful structure–property (gelation) correlation. MTT assay of the hydrogelators in the mouse macrophage RAW 264.7 cell line showed excellent biocompatibility. The prostaglandin E2 (PGE2) assay of the hydrogelators revealed their anti-inflammatory response, which was comparable to that of the parent NSAID naproxen sodium (Ns).