Preparation of a Paeonol-Containing Temperature-Sensitive In Situ Gel and Its Preliminary Efficacy on Allergic Rhinitis

In this paper, the optimal composition of a paeonol temperature-sensitive in situ gel composed of poloxamer 407 (P407) was determined, and a preliminary study of its effect on allergic rhinitis was performed. The optimal composition of the paeonol temperature-sensitive in situ gel included 2% paeonol inclusion, 22% P407, 2% poloxamer 188 (P188) and 2% PEG6000, as assessed by thermodynamic and rheological studies. The toad palate model was employed to study the toxicity of the paeonol temperature-sensitive in situ gel on the nasal mucosa. The result of this experiment showed low toxicity to cilia, which allows the gel to be used for nasal administration. The Franz diffusion cell method was used to study the in vitro release of paeonol and suggested that the in vitro release was in line with the Higuchi equation. This result suggests that the paeonol could be absorbed into the body through mucous membranes and had some characteristics of a sustained effect. Finally, the guinea pig model of ovalbumin sensitized allergic rhinitis was used to evaluate the preliminary efficacy of the gel, with the paeonol temperature-sensitive in situ gel showing a significant effect on the guinea pig model of sensitized allergic rhinitis (AR).