Tripterygium wilfordii (Tripterygium wilfordii) is a perennial vine of Euonymus family. It tastes bitter, pungent, cold, highly toxic and has immunosuppressive effect. Tripterygium wilfordii is widely used in the treatment of vasculitis, lupus erythematosus, eczema, psoriasis, systemic scleroderma, allergic purpura, nodular erythema, skin amyloidosis, Behcet's disease and other skin diseases, as well as nephropathy and rheumatoid arthritis. But Tripterygium wilfordii is a toxic traditional Chinese medicine. Tripterygium wilfordii has obvious reproductive toxicity and hepatorenal toxicity. Statistics show that the incidence of adverse reactions of Tripterygium wilfordii preparations is as high as 11.7%. The old saying goes, "Licorice is detoxifying". Modern research shows that licorice can antagonize the toxicity of Tripterygium wilfordii to a certain extent and improve the curative effect, reflecting the characteristic advantages of traditional Chinese medicine compatibility for reducing toxicity and increasing efficacy. In order to reduce the toxicity of triptolide, the main active ingredients of Tripterygium wilfordii and glycyrrhetinic acid were prepared into triptolide-glycyrrhetinic acid compound microemulsion. The purpose of this study was to reduce the toxicity of triptolide through compatibility, and make use of the advantages of small particle size and good biocompatibility of nano-preparations to achieve the purpose of reducing toxicity and increasing efficiency.
Glycyrrhetinic acid is the hydrolysate of glycyrrhizic acid, which is the main active ingredient of liquorice. It has the functions of anti-allergy, immune regulation, anti-tumor, detoxification, liver protection and anti-oxidation. It is commonly used in clinic to replace hormones in the treatment of immune diseases and cancer. Combined with other drugs, it can effectively treat skin diseases such as neurodermatitis, chronic eczema, chronic urticaria and alopecia areata.
The results of in vitro release test showed that the release rate of the two main components in single microemulsion was faster than that of compound microemulsion. It was speculated that the complex of triptolide and glycyrrhetinic acid could slow down the release rate and achieve the effect of attenuation. In addition, based on the anti-allergic and immunomodulatory effects of glycyrrhetinic acid, the triptolide-glycyrrhetinic acid microemulsion prepared in this study can play a dual regulatory role in the treatment of immune diseases, and has the dual role of reducing toxicity and increasing efficiency, which provides a new research idea for the clinical application of toxic traditional Chinese medicine.
In conclusion, the method established in this study is simple and accurate, and the optimized formulation is stable and feasible. The prepared triptolide-glycyrrhetinic acid compound microemulsion has better sustained-release effect than single microemulsion.