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 beta-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 H-1 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 E-2 (PGE(2)) assay of the hydrogelators revealed their anti-inflammatory response, which was comparable to that of the parent NSAID naproxen sodium (Ns).