Preparation and characterization of Quercus Infectoria Galls pH/temperature sensitive gels

BAI Jiao-jiao; DING Yan; SABAHAT Ablimit; ZHAO Wen-hui; KUDELAID Kuerban; MUBARAK Iminjan

doi:10.3969/j.issn.1003-3734.2024.22.012

Abstract：Objective:To optimize and characterize the prescription process of Quercus Infectoria Galls pH/temperature sensitive gel(QIG-pH-TSG).Methods:QIG-pH-TSG was prepared using cold solubilization method,with poloxamer 407(P407),poloxamer 188(P188),sodium alginate(SA),hydroxypropyl methylcellulose(HPMC)as excipients,and Quercus Infectoria Galls(QIG)ethanol extract as the raw material drug,and gel temperature,viscosity before and after gelation,and cumulative in vitro release were examined as the indexes.The response surface method was used to optimize the prescription process,the microscopic morphology of the gel was observed using scanning electron microscopy(SEM),its rheological behavior before and after the phase transition was investigated using rheometer,and its thermal stability was analyzed using differential scanning calorimetry(DSC).Results:The optimal prescription composition of QIG-pH-TSG was as follows:P407 23％,P188 1.77％,SA 0.53％,and HPMC 1.06％.The prescription had gel temperature of(33.48±0.33)℃,pre-gel viscosity of(0.84±0.04)Pa·s,post-gel viscosity of(1 068.61±21.79)Pa·s,and cumulative release in simulated artificial colonic fluids at 24 h of(96.34±5.66)％.SEM observation of the microscopic morphology revealed that the blank gel was porous with a loose structure;QIG-pH-TSG was uniformly dispersed,and the voids were filled.Rheological studies revealed that QIG-pH-TSG was a Newtonian fluid with no yield stress at 4 ℃ and 25 ℃,and a pseudoplastic fluid with yield stress and stable cross-linking structure and no thixotropy at 37 ℃.DSC analyses showed that QIG-pH-TSG was stable in physiological environments.Conclusion:The optimized QIG-pH-TSG has good temperature and pH sensitivity and provides a basis for a new dosage form for the treatment of ulcerative colitis(UC).