Preparation Of Enrofloxacin Nanosuspension Injection And Its Pharmacokinetics In Swine

This study aimed to preparate enrofloxacin nanosuspension injection,which made enrofloxacin as raw materials,adding suitable amount of suspending agen,stabilizer,surfactant and other pharmaceutic adjuvant,with orthogonal design to selecte the formulas,by using high pressure homogeneous technology.Then the pharmacokinetic studies were made in pigs.Through the indexes of appearance,p H,sedimentation volume,dispersion,particle size,Zeta potential,and so on to evaluate the quality of this preparation.Meanwhile,in accordance with the requiremengs of influenced factors and accelerated tests to inspect the stability.Results indicated that indexes had no significant changes,showing the good stability of this preparation,which matched with the demands of preparation of suspension.A high performance liquid chromatography method was developed for the determination content of enrofloxacin in pigs plasma.Through the detection of plasma samples,the limit of detection and quantification were 0.025?g/mL and 0.05?g/mL,respectively.The correlation coefficients for all of the compounds were greater than 0.999over a dynamic range of 0.025-10?g/mL.The mean recoveries of target compounds obtained for low,middle,high spiking levels range from 88.9%to 102.7%.The intra and inter-day relative standard deviations ranged from 2.4%to 3.2%and 2.5%to 3.8%,respectively.The results showed this study obtained a higher sensitive and accuracy method,which was applied to detect the content of enrofloxacin.Twelve health and hybrid pigs?23.0±4.5 kg?were choosed to make experiment.Using latin square design to make the pharmacokinetics study of pigs,which were given a single intramuscular administration of enrofloxacin nano-suspension injection and Baytril injection?2.5 mg/kg.b.w.?at the same time in the study,respectively.The enrofloxacin in plasma were determined by high performance liquid chromatography?HPLC?method.The main pharmacokinetic datas were dealed by atrioventricular model of the pharmacokinetic software Winnonlin 5.2.1.The main pharmacokinetic parameters of enrofloxacin nano-suspension injection were as follows:C_max 0.32±0.12?g/mL,T_max 2.88±0.96 h,t_1/2?5.99±1.37 h,AUC_last 4.63±1.30?g·h/mL,MRT_last 9.59±2.34 h.The main pharmacokinetic parameters of Baytril injection were as follows:C_max 0.67±0.09?g/mL,T_max 0.79±0.26 h,t_1/2?4.49±1.25 h,AUC_0-last 4.40±0.45?g·h/mL,MRT_0-last 5.41±1.10 h.Compared with Baytril injection,the relative bioavailability of enrofloxacin nano-suspension injection was105.2%.The main pharmacokinetic parameters were analysed by SPSS statistical analysis software,and the results indicated that T_max and t_1/2ke of enrofloxacin nano-suspension injection were significantly increased,MRT_last were significantly prolonged,the statistical differences were significantly?P<0.01?.The results showed that the enrofloxacin nano-suspension injection had a slow-release effect and eliminated relatively slowly eliminate the slow.