Study On Clarithromycin Ester Submicron Emulsion Injection

Clarithromycin(CLA)is a semi-synthetic macrolide antibiotic.It is mainly used for the remedy of upper and lower respiratory tract infections and is the priority drug for community-acquired pneumonia.CLA raw material itself tastes bitter and is insoluble in water and oil.It has the characteristics of strong irritation and easy to cause vasospasm.Oral CLA is prone to non-compliance and requires frequent administration.Common side effects are nausea,poor taste and low sodium,as well as ventricular tachycardia in severe cases.The commercially available CLA injection can also cause phlebitis due to its high irritation level.Therefore,to prefer to utilize the advantages of CLA,adapt to clinical needs,and reduce adverse effects such as irritation,this study simply modified CLA and prepared a submicron emulsion dosage form available for intravenous injection.The antibacterial activity and safety evaluation of clarithromycin ester submicron emulsion injection in vivo and in vitro were further systematically studied.It is planned to reduce the irritation of CLA,increase the drug loading and broaden the application scope.Clarithromycin ester(CLA-Pal)was synthesized by ‘esterification reaction’ using CLA.It is simple,fast,environmentally friendly,and pollutant-free,and yields high enough for industrial use.By analytical methods,it was determined that the 2’-hydroxyl location is esterification occurs.CLA-Pal pre-prescription study.UV full wavelength scanning determined the maximum wavelength of absorption of CLA-Pal at 298 nm.In vitro HPLC analysis was established.The solubility of CLA-Pal in different p H values,soybean oil and medium chain oil was investigated,and the oil-water partition coefficient of CLA-Pal was investigated.It indicated that CLA-Pal had poor water solubility and strong fat solubility,which was40 times higher than that of CLA in soybean oil and MCT.The molecular docking of CLA-Pal and CLA with the receptor protein(PDB ID: 4V7S)was analyzed in comparison.The results showed that the CLA-Pal combined better with the protein and occupied the site more easily.Additionally,the hydrophobicity and volume of the esterified compound increased,thereby affecting the active site of the protein.Study on the formulation and technology of CLA-Pal submicron emulsion.According to the strong fat solubility of CLA-Pal,the drug can be directly dissolved in the oil phase without other solubilizers.In this part,the range of excipients and preparation process in the prescription ware obtained by single-factor investigation.The prescription and process were further optimized by orthogonal method to obtain the optimal parameters: CLA-Pal2.67%,soybean oil 2.5%,medium-chain triglyceride 7.5%,egg yolk lecithin1.8%,Tween 80 0.75%,poloxamer 0.75%,sodium oleate 0.05%,glycerol2.5%.The colostrum was prepared at 70 ℃,sheared at 10000 rpm for 10 min,and homogenized at 1000 bar for 10 times.The prepared submicron emulsion has good appearance and stability.Study on stability and quality of CLA-Pal submicron emulsion.The average particle size of submicron emulsion was 125 nm,the absolute value of zeta potential was 30 mv,the p H was 7～8,the encapsulation rate was 90%on average,It had good appearance,good fluidity,no hanging wall,and blue opalescence can be obviously seen through light.TEM and SEM in vitro characterization evinced that the submicron emulsion was spherical and uniform in size.The results showed that CLA-Pal submicron emulsion should be kept at low temperature and away from light.The stability was good for 6 months at 5 ± 3 ℃ and 25 ± 3 ℃.The influencing factors affecting the quality of the submicron emulsion were examined.According to the results,the free fatty acids,glycerol,peroxide and methoxyaniline content met the requirements.In vitro antibacterial studies of CLA-Pal submicron emulsion.In this chapter,the MIC and MBC of CLA,CLA-Pal and CLA-Pal submicron emulsion in different strains were determined by double dilution method.The growth curve of S.aureus biofilm was explored,which stated clearly that the drug had inhibitory effect on S.aureus biofilm and could significantly reduce the number of live bacteria.The effects of drugs on bacteria were studied by bacterial growth inhibition curve,fluorescence microscope and scanning electron microscope.The test results showed that CLA-Pal submicron emulsion had good antibacterial activity in vitro.In vivo antimicrobial study of CLA-Pal submicron emulsion mouse.CLA is the first choice drug for community-acquired pneumonia(CAP).It is extremely important to investigate the effect of esterified prodrug CLAPal on CAP.In this chapter,we explored different modeling methods,and finally made the model by intubation.Taking the changes of wet-dry weight index(W/D)of lungs,bacterial load(BALF,heart,liver,spleen,lung,and kidney),changes of inflammatory factors and pathological tissue sections as evaluation indexes,the bacterial community-acquired pneumonia was established,and the self-made CLA,CLA-Pal injection CLA-Pal submicron emulsion injection was used to treat model mice.After the successful CAP modeling,the mouse suffered from mental depression,slow movement,shortness of breath,decreased appetite and other symptoms.It was remarkably increase in W/D index,white blood cell count and neutrophil count,and TNF-α,IL-1β,IL-18,and IL-6 inflammatory factors.After drug treatment,the increased in W/D index,tissue bacterial load,inflammatory cells and inflammatory factors decreased.The results of HE sections of the pathological tissue of the lungs showed that the alveolar structures were nearly intact,the alveolar walls were not thickened,and there were bits of inflammatory cells and erythrocytes in the alveolar lumen.It known that CLA-Pal submicron emulsion injection had critical results in the treatment of bacterial CAP.The safety of CLA-Pal submicron emulsion was investigated.There was not cytolytic hemolysis occurred in CLA-Pal submicron emulsion.Vascular irritation,foot licking test in rats and scratch test in mice indicated that the irritation of submicron emulsion was lower than that of CLA injection and CLA-Pal injection.Preliminary toxicological examination known that after 5 days of continuous administration,the living state,mental state,biochemical indexes,blood routine,and HE tissue section of mouse that there was not a significant difference between the submicron emulsion group and saline group.In conclusion,it indicated that CLA-Pal submicron emulsion injection was suitable for intravenous injection with low irritation,good safety and low toxicity.