| Ticagrelor,non-thiophenopyridine and non-precursor drug,can directly play the role of anti-platelet aggregation without going through liver metabolism.It is widely used in clinical practice due to rapid adsorption and reversible combination with P2Y12 receptor.Because ticagrelor belongs to BCS IV,its half-life short and main absorption site in the middle and upper of the small intestine,resulted in its low oral bioavailability.In this paper,ticagrelor-load liposomes were prepared by thin film dispersion method.Liposomes and biological adhesive materials combine with electrospray technology to prepare solidified liposome microspheres（SL-MS）,electrospray technology can effectively avoid the problems of bilayer structure destruction and membrane melting of liposomes contract to traditional method in process of solidified liposome.According to characterization of SL-MS,construct thrombus model and the pharmacokinetic study in rats,showed that the electrospray technology is a simple and feasible method to solidified liposomes.This paper is divided into the following five parts.Part Ⅰ:ReviewFirstly,this part briefly introduced the current situation of acute coronary syndrome（ACS）and the clinical treatment of ACS.Secondly,the physical and chemical properties of ticagrelor were introduced,and the research progress of liposomes and the role of liposomes as carriers in drug delivery system were summarized.Finally,the concept and application of electrospray technology in drug field were introduced,and its application in drug delivery system were emphasized.Part Ⅱ:Preformulation studiesIn this part,some basic physicochemical properties of ticagrelor were introduced.The absorption wavelengths of ticagrelor were obtained at 220 nm,260 nm,and 290 nm by UV spectrophotometer.The apparent solubility of ticagrelor in water at three different temperatures were 12.61±0.76μg/m L,32.04±2.20μg/m L and 49.56±0.86μg/m L,respectively.The oil-water partition coefficients of the drugs at 0.2 mg/m L and 1.0 mg/m L were 3.71±0.04 and 3.73±0.01 by the shake flask method.A high-performance liquid chromatography（HPLC）was developed to determine the concentration of ticagrelor.This method is precise,convenient,reliable and good recovery,and the solution have no effects on determination.The detection results conformed the linear requirements in the concentration range of 0.5 to 80μg/m L.Part Ⅲ:Preparation and characterization of ticagrelor-load liposomesIn this part,liposomes were prepared by thin film dispersion method,ether injection method and reverse evaporation method,respectively.The particle size was 60-120 nm,20-180 nm,and60-150 nm,respectively.The encapsulation efficiency was 88.56%,57.78%and 67.50%,respectively.The particle size of liposomes was observed by transmission electron microscopy（TEM）.The TEM results showed that the surface of liposomes was smooth and round with uniform particle size distribution by thin film dispersion method.The formulation of liposome was optimized by orthogonal design test.The particle size and zeta potential of liposome suspension was about 120 nm and-25.78±2.43 m V,respectively.The final formulation of liposome was the concentration of phospholipid was 5%,and the quality ratio of drug to phospholipid was 1:12,and the quality ratio of cholesterol to phospholipid was 1:10,and the quality ratio of sodium cholate to phospholipid was 1:5.The dissolution experiment of liposome suspension showed that the release degree was over 30%after 2 h and the delamination appeared after storage for more than30 days.Part Ⅳ:Preparation and Characterization of Bioadhesive liposome microsphere based on electrospray technologyIn this section,electrospray technology was used to prepare SL-MS.The morphology,particle size and encapsulation efficiency of the SL-MS were used as the main indexes to optimize preparation process based on single factor study and response surface center composite design.The SEM results showed that the surface of the SL-MS was smooth and round with uniform particle size distribution.The FTIR and XRD of SL-MS results showed that the characteristic vibration absorption peak of the drug was changed obviously,and peak of the drug in the X-ray diffraction pattern was decreased obviously,and the results indicated that the ticagrelor was present an amorphous state in the SL-MS.The dynamic light scatterer（DLS）showed that the particle size of SL-MS was in the range of 500 nm to 1400 nm,and zeta potential was-43.55±2.30 m V.The dissolution experiment showed that the release of drug was less than 20%at 2 h,and the SL-MS had a good stability compared with the liposome suspension,and the bioadhesive rate of the SL-MS of containing 0.66%carbomer was 33.09±3.41%.In addition,the safety evaluation of the SL-MS by MTT showed that the cell survival rate was more than 100%when the concentration of the SL-MS was in the range of 10 to 400μg/m L,the results indicated that the SL-MS had high safety,which met the requirements for in vivo experiments.Part Ⅴ:Pharmacokinetics and pharmacodynamic evaluation in vivoIn this section,the concentration of ticagrelor in rat’s plasma was determined by HPLC,and the linear relationship was good in the range of 0.03 mg/L to 0.4 mg/L,and the feasibility of the method was verified.In vivo pharmacokinetic results showed that compared with the oral drug administration,the concentration of SL-MS was 33.82±3.23 mg/L at 24 h,the elimination half-life increased from 12.46 h to 69.32 h.The mean residence time（MRT）in the body also increased from 13.96 h to 26.92 h,and the AUC of SL-MS increased to 249%,the results indicated that the SL-MS prepared by electrospray technology can increase the drug residence time and improve the bioavailability of oral administration.Finally,the antithrombotic effect of SL-MS was evaluated through the ICR mouse thrombus model,compare with the antithrombotic effect of API and SL-MS and model group.The results showed that thrombus lengths in each group were 14±2.61 mm,10.67±2.58 mm,and 49.5±11.54 mm at 48 h,respectively,the results indicated that the SL-MS prepared by electrospray technology had a good antithrombotic effect.HE staining results showed that the structure of liver cells was normal,the results indicated that the SL-MS was prepared by electrospray have better safety. |
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