Highlighting the Anti-Inflammatory Activity of Topical Gels Loaded with Meloxicam: The Role of Different Excipients and Absorption Promoters.

Thermosensitive polyurethane (PU) hydrogels were prepared and loaded with meloxicam (MX), a nonsteroidal anti-inflammatory drug (NSAID). The role of different excipients, i.e., eucalyptus essential oil as well as poly(vinylpyrrolidone), poly(ethylene glycol) and their mixture, was highlighted. The sol-gel transition induced by temperature increase was evidenced by rheological measurements in oscillatory shear conditions. The viscoelastic behavior was investigated at 37 °C in various shear conditions, evidencing the network strength and stability of formulations. The structural recovery was monitored after applying high strain values, and the self-healing ability was revealed. Depending on the excipient, the gel samples loaded with MX release between 60% and 90% of the active substance. It was shown that the Fickian and chain relaxation contributions compete during MX release from PU-based hydrogels. In vitro anti-inflammatory activity was evaluated and discussed.