Preparation Of Tofacitinib Sustained-release System And Its Performance In The Treatment Of Rheumatoid Arthritis

The pathogenesis of rheumatoid arthritis(RA)is related to environmental,sex hormone,genetic and other factors,affecting 0.5%-1% of the global population,and there are certain differences in age,gender,race and region.RA has a long course of disease,and the clinical goal of drug treatment is to alleviate or control RA disease activity,alleviate patient pain,and control the course of disease.Continuous and frequent drug treatment not only causes severe liver burden,but also serious toxic and side effects and drug tolerance,reducing patient compliance.The JAK-STAT pathway is responsible for signal transduction of various inflammatory cytokines and chemokines.Tofacitinib(TF),as the first approved JAK inhibitor for the treatment of RA,can reduce inflammatory reaction,improve RA condition,avoid irreversible joint injury as much as possible and improve the quality of life of patients by inhibiting JAK-STAT pathway.However,it has some problems such as short half-life and large toxic and side effects caused by long-term frequent administration.The drug sustained-release system can provide long-term effective treatment effect,which can reduce the toxic and side effects of drugs by reducing the administration times,and has good application prospect in the treatment of chronic diseases such as RA.Silk fibroin has great advantages in drug loading and sustained release due to its excellent biocompatibility,mechanical properties,and degradability.Poly(lactic-co-glycolic acid)(PLGA)sustained-release microspheres are the most commonly used drug delivery system.Due to their biodegradability,low drug toxicity and non-toxic degradation products,they have also been widely used in medical applications.To sum up,two different drug delivery systems,silk fibroin gel and PLGA particles,were developed.The specific content is as follows:(1)Preparation of silk fibroin-sodium oleate-tofacitinib(SFOA-TF)gel and its performance in RA.In this study,SF-OA-TF gel with a narrow particle size distribution and a certain drug loading and long-term sustained release effect(more than 13 days)was prepared by using sodium oleate as a gelling agent and silk fibroin(SF)as drug carrier.SF-OA-TF gel can enter RAW264.7 cells by cellular uptake and shows very low cytotoxicity,which can effectively inhibit the cell migration and the expression of three inflammatory factors of IL-6,IL-1β and TNF-α in the presence of inducing factors,and shows certain concentration dependence.In vivo pharmacodynamic study.We evaluated the therapeutic effect of SF-OA-TF gel administered by subcutaneous injection on collagen-induced arthritis(CIA)mice model by measuring the weight change and joint swelling degree of mice,combining with joint scoring standard and inflammatory factor detection.The results showed that the conditions of mice in TF group and SF-OA-TF group were significantly improved,and the therapeutic effect of SF-OA-TF group was more obvious than that of TF.Its long-acting and slow-release characteristics has good application prospect for improving the clinical treatment of RA.(2)Preparation of poly(lactic-co-glycolic acid)-tofacitinib sustained-release nanopar-ticles(NanoTF-PLGA)by high gravity nanoprecipitation and its performance in rheumatoid arthritis.We successfully prepared NanoTF-PLGA by using high-gravity nano-precipitation technology,and verified its therapeutic effect on rheumatoid arthritis through in vitro and in vivo experiments.The results showed that the prepared NanoTF-PLGA had smaller average particle size(603.8 nm),more uniform shape,higher drug loading(7.64%)and long-term sustained release effect(more than 9 days).In vitro experiments showed that NanoTF-PLGA could enter RAW264.7 cells by cellular uptake and showed very low cytotoxicity,which can significantly inhibit RAW264.7 cell migration and inhibit the expression of three inflammatory factors of IL-6,IL-1β,and TNF-α in a dose-dependent manner.In vivo pharmacodynamic study.The therapeutic effect of NanoTF-PLGA on CIA model mice was evaluated by measuring the weight change and joint swelling degree of mice,combining with joint scoring standard and inflammatory factor detection.The results showed that subcutaneous injection of TF group and NanoTF-PLGA group could significantly alleviate articular cartilage injury and reduce inflammatory cell infiltration around joint cavity,and the effect of NanoTF-PLGA group was more significant.In summary,NanoTF-PLGA prepared by using the high-gravity nano-precipitation technology and administered by subcutaneous injection has a good therapeutic effect.Meanwhile,the preparation method is simple to operate,low in cost and free of industrial amplification effect,and has great application potential in the treatment of RA.