| Florfenicol is a novel animal-specific amidohydrin broad-spectrum antibiotic.At room temperature,the solubility of florfenicol in water is very low,which greatly limits its wide application.The cyclodextrin inclusion technique is a technique for improving the solubility of poorly soluble drugs and has been widely used in pharmacy.In order to improve the solubility of FF,FF/HPCD inclusion complex freeze-dried powder injection was prepared by solution agitation combined with freeze-drying,and the related characterization and quality evaluation were researched.Finally,taking the 10%florfenicol injection as a reference,the pharmacokinetic properties of the preparation in beagle dogs were studied and the expected results were The experimental results are as follows:1.Solution agitation method was used to prepare the FF/HPCD inclusion complex.Taking drug loading and encapsulation ratio as indicators.Through single factor screening the ratio of host to guest feed,the type and amount of organic solvents,the concentration of cyclodextrin,the pH of the reaction system,inclusion temperature,stirring rate and inclusion time and other indicators were investigated,combined with orthogonal test of FF/HPCD inclusion complex freeze-dried powder prescription and inclusion process were optimized.The optimum prescription and process were as follows:the molar ratio of HPCD to florfenicol was 2:1,the concentration of methanol was 50%,the mass concentration of HPCD was 20%,the pH of the reaction system was 5.0,the stirring temperature was 30?,the stirring rate was 100 rpm and the stirring time was 2 h.The freeze-drying method was used to dry the inclusion complex.The lyophilization process was optimized by a single factor test.The final freeze-drying process was:pre-frozen at-30?for 4 h,freeze-drying procedure-50?for 16 h,30?sublimation drying 4 h.The FF/HPCD inclusion complex freeze-dried powder injection was successfully prepared by the above process conditions.2.FF,HPCD,physical mixture of the two and FF/HPCD inclusion complex freeze-dried powder were characterized by phase solubility,SEM,DSC,XRD,FT-IR and 1H-NMR.The results of SEM,DSC,XRD and FT-IR showed that florfenicol was entrapped into the inner cavity of HPCD,and the inclusion complex formed in an amorphous state.The results of phase solubility and 1H-NMR showed that the two groups reacted at a 1:1 inclusion ratio,and florfenicol was mainly embedded into the molecular cavity of HPCD from the upper end of the wide mouth.3.The quality evaluation of FF/HPCD inclusion complex freeze-dried powder injection was carried out in terms of appearance,clarity,content,pH value,solubility,pyrogen,hemolytic and injection irritation.And through the influence factor test to carry on the stability inspection to it.The appearance of the prepared freeze-dried power injection is a white loose,smooth and flat powdery solid;the clarity of the lyophilized powder after reconstitution meets the requirements;the drug content is11.78%±0.04%;the pH value is 6.92±0.03;the saturation solubility in water at 37?was 78.93±0.42 mg/mL,which was about 35.4 times higher than that of 2.22±0.04mg/mL of FF;the pyrogen test was in line with the determination result;the hemolysis rate was less than 5%,which could be used for injection;the inclusion complex lyophilized powder has less irritation for intramuscular injection compared to the 10%florfenicol injection.The results of influencing factor test showed that FF/HPCD inclusion complex freeze-dried powder can resist with high temperature and strong light environment,but with strong hygroscopicity,to be preserved in dry conditions.4.Pharmacokinetic behaviors of 10%florfenicol injection and FF/HPCD inclusion complex freeze-dried powder injection in the beagle dogs were compared.The DAS 2.0 system was used to fit the plasma concentrations at different time points after administration.The results showed that the pharmacokinetic data of the two formulations accord with the first-order absorption kinetics two-compartment model.The main pharmacokinetic parameters of the common florfenicol injection group in beagle dogs were as follows:Cmax was 11.559±1.544 mg/L,Tmaxax was 0.583±0.129 h,V1/F was 1.107±0.208 L/kg,CL/F was 0.871±0.140 L/h/kg,AUC?0-t?was21.638±2.379 mg/L*h,AUC?0-??was 23.652±2.391 mg/L*h,respectively.Accordingly,the parameters of inclusion complex group with the same dose of florfenicol were as follows:Cmax,Tmax,V1/F,CL/F,AUC?0-t?and AUC?0-??were15.896±3.147 mg/L,0.444±0.086 h,0.719±0.171 L/kg,0.808±0.082 L/h/kg,22.134±2.882 mg/L*h,and 24.543±2.841 mg/L*h,respectively.Compared with 10%florfenicol injection group,the FF absorption rate of the inclusion complex group was faster,the peak time(Tmax)and the maximum plasma concentration(Cmax)significantly increased?P<0.05?,the area under the curve AUC?0-t?and AUC?0-??was not significantly different,and the relative bioavailability of the two was 102.3%.The above results show that FF/HPCD inclusion complex freeze-dried powder injection can be used as an effective injection of florfenicol,which indicate this formulation has wide application prospect in clinical and its clinical trials need to be further study.In this study,FF/HPCD inclusion complex freeze-dried powder injection was successfully prepared by solution stirring combined with freeze-drying.At the same time,various characterizations and quality evaluations were carried out.This formulation increased the solubility of FF in water significantly,reducing intramuscular irritation compared to the FF common injection greatly,and improved it's pharmacokinetic properties in beagle dogs significantly. |
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