Study On Ticagrelor-loaded Lipid Nanocapsules

Ticagrelor is a novel antiplatelet drug that reversibly binds to the P2Y₁₂receptor,and is mainly used for acute coronary syndrome and percutaneous coronary intervention.However,ticagrelor has poor solubility and permeability,and low oral bioavailability,which affects its oral efficacy.Therefore,this project intends to develop ticagrelor-loaded lipid nanocapsules（TGL-LNC）to improve the solubility and permeability of ticagrelor and enhance its oral pharmacological activity.The main research contents and results of this project are as follows.（1）Pre-formulation study of ticagrelor-loaded lipid nanocapsulesA method for the determination of ticagrelor was established and validated by high-performance liquid chromatography.The equilibrium solubility of ticagrelor drug substance in water,p H 1.2 hydrochloric acid solution,p H 4.5 acetate buffer,and p H 6.8 phosphate buffer were determined.The experimental results show that the solubility of ticagrelor in p H 1.2 hydrochloric acid solution was the largest,which was 14.954±0.005μg/m L,and the solubility in p H 4.5 acetate buffer solution was the smallest,which was only 7.397±0.017μg/m L,indicating that the ticagrelor is a low soluble drug.（2）Preparation of ticagrelor-loaded lipid nanocapsulesUsing solubility experiments and compatibility experiments,Labrafil M 2125CS was preliminarily determined as an oil phase,Kolliphor HS15 was used as a surfactant,and Transcutol HP was selected as a co-surfactant.The optimal formulation and preparation process was determined by single factor tests,pseudo-ternary phase diagrams,and D-optimal mixture design.In the 4 g formulation,the amount of Labrafil M 2125CS was 200.0 mg,the amount of Kolliphor HS15 was559.5 mg,the amount of Transcutol HP was 186.5 mg,and the amount of water was1054.0 mg.The amount of egg yolk lecithin is 31.0 mg,the amount of Na Cl is 36.2mg,the volume of the diluted aqueous phase is 2 ml,and the amount of drug is 80 mg.In the preparation process,the stirring speed was 720 rpm and the number of cycles was 3 times.（3）Pharmaceutical evaluation of ticagrelor-loaded lipid nanocapsulesThe physicochemical properties of TGL-LNC were characterized by transmission electron microscopy,particle size and potential analyzer,and high-speed refrigerated centrifuge.TGL-LNC was microscopically spherical with a mean particle size of 24.64±0.13 nm,and a PDI of 0.190±0.021.The average zeta potential was-3.97±1.07 m V,the entrapment efficiency was 98.12±0.46%,the drug loading efficiency was 7.48±0.04%,and the concentration reached 20.70±0.25 mg/m L of TGL-LNC.In vitro release studies of TGL-LNC were performed by dialysis.The experimental results showed that the release of ticagrelor suspension was slow in p H1.2 and p H 6.8 release media,while the release of TGL-LNC was significantly faster.The in vitro release of TGL-LNC in p H 1.2 hydrochloric acid solution conformed to the Hixcon-Crowell equation,and the release mechanism was matrix erosion,while the in vitro release in p H 6.8 phosphate buffer conformed to the Ritger-Peppas equation,and the release mechanism was Fick diffusion combined with matrix erosion.The stability of TGL-LNC was investigated using cold-heat cycle experiments,and storage experiments.The experimental results showed that the TGL-LNC had good stability.（4）In vitro intestinal absorption study of ticagrelor-loaded lipid nanocapsulesA method for the determination of ticagrelor in the intestinal fluid was established and validated by high-performance liquid chromatography.The absorption characteristics of the duodenum,jejunum,and ileum of rats with TGL-LNC were evaluated by the everted intestinal sac method.The experimental results showed that the cumulative absorptions of TGL-LNC in the duodenum,jejunum,and ileum were 2.04,2.19,and 1.73 times higher than that of ticagrelor within 2 h,respectively.Compared with ticagrelor,the P_appof TGL-LNC in the duodenum,jejunum,and ileum were significantly increased,and the absorption promoting ratios were 2.00,2.20,and 1.91,respectively,indicating that TGL-LNC improved the intestinal permeability of ticagrelor.The jejunum was the main intestinal segment for TGL-LNC absorption.（5）Pharmacodynamic evaluation of ticagrelor-loaded lipid nanocapsulesThe clotting time and bleeding time of TGL-LNC were investigated by capillary method and tail-cut method,respectively.TGL-LNC significantly enhanced the anticoagulant effect of ticagrelor without increasing the risk of bleeding.The antithrombotic effect of TGL-LNC was evaluated by the mouse tail thrombus model.The experimental results showed that after 48 hours of modeling in each group,the black tail rate of the thrombus model group was 73.37±4.98%,while the black tail rate of the ticagrelor group and the TGL-LNC group were 38.88±10.51%and27.56±10.29%,and the 48-hour thrombosis inhibition rates were 47.00%and62.44%,respectively,indicating that TGL-LNC significantly enhanced the antithrombotic effect of ticagrelor.The platelet aggregation inhibitory effect of TGL-LNC was evaluated by the microplate method.The experimental results of the anti-platelet aggregation experiment showed that the maximum platelet aggregation rate was 26.53±5.27%in the control group and increased to 35.99±9.27%in the model group.However,the maximum platelet aggregation rate of the ticagrelor group and TGL-LNC group decreased to 10.85±3.08%and 5.87±2.18%,respectively,and the platelet aggregation inhibition rates were 69.84%and 83.70%,respectively.This indicated that the formation of thrombus in the model group enhanced platelet aggregation,while TGL-LNC enhanced the antiplatelet aggregation activity of ticagrelor.In conclusion,TGL-LNC was successfully prepared and evaluated in vitro and in vivo.On the one hand,the preparation process of TGL-LNC is stable and controllable,which improves the solubility of ticagrelor,promotes drug release,and has good stability.On the other hand,TGL-LNC enhances the intestinal permeability and pharmacological activity of ticagrelor.