Thermosensitive and pH-responsive quercus infectoria gall-containing gel with long-lasting anti-inflammatory activity for ulcerative colitis

In the study, quercus infectoria gall (QIG) was used to develop a pH/thermosensitive gel in situ delivery system for enema administration of to treat acute ulcerative colitis (UC). The QIG ethanol extract pH/temperature-sensitive gel (QIG-pH-TSG) was characterized by using DSC, SEM, rheological and drug release analyses. The therapeutic effect in UC mice of the obtained gel were studied. The gel was maintained in a flowing liquid state under nonphysiological conditions (25 °C) to facilitate drug administration, and was transformed into a pseudoplastic liquid state under physiological conditions (37 °C), which prolonged its retention time in the colon. The gel drug was completely released within 24 h, and the temperature and viscosity of the gel were within the required range. In the