Degradation And Delayed Release Of Enrofloxacin Polylactide-Poly Trimethylene Carbonate In Vitro And Vivo

This experimentation used new biodegradable polymer Polylactide-Poly trimethylene carbonate(PLA-PTMC),in which we added in veterinary medicine Enrofloxacin,and made it to thinness test pieces and embedded it into muscle of rabbits, back bone,then we observing the speed of degradation,the effect to the growth of organization and the condition of delayed release medicine of these test pieces in vivo,and meanwhile we observing the speed of degradation,the condition of slow release drug of these test pieces in neutrol environment(PBS fluid) in virto,through which we studied the degradation,delayed release and biocompatibility of PLA-PTMC . The result of this experimentation as follow:Degradation:The degradation in vivo was quicker than in virto. In virto,the degradation rate of PLA-PTMC test pieces was 32.65%,and that of En-PLA-PTMC test pieces was 48.0% at the 110th day. In vivo,the degradation rate of PLA-PTMC test pieces was 10.71%,and that of En-PLA-PTMC test pieces was 18.75% at the 42th day. At the 70th day,PLA-PTMC test pieces were not completely break into pieces,but En-PLA-PTMC test pieces were completely break into pieces,and tissues grown into test pieces,we could not separate them.Delayed release:In delayed release test pieces,the proportion of polymer and medicine quality is 2:1,the ratio of embedding medicine is 30%. The delayed release speed of test pieces was very slowly at the first two weeks in neutrol environment(PBS fluid) in virto,after the 2th week,delayed release speed started to speed up,and the delayed release rate was shoot up at fllowing time. The ratio of delayed release medicine was up to 79.68% at the 10th week. In vivo,form the second week,the blood drug level could be detdcted and was increasing,the blood drug level was up to maxlmum at the 8th week. Part Enrofloxacin metabolism to Ciprofloxacin in vivo and the Ciprofloxacin concentration was higher than the Enrofloxacin concentration.Biocompatibility:The activity of all rabbits was normal after test pieces were implanted into rabbits body. The cut were free from infection and the condition of heal was good. Form the seciend week to the forth week,muscles by the surrounding test pieces had inflammatory reaction that could be see by naked eyes,but which was not effect the activity and living of rabbits. Amicula were formed surrounding the test pieces and amicula disappeared at the sixth week,meanwhile test pieces started to break into pieces,tissues grown into test pieces,inflammatory reaction disappeared gradually. We observed tissue section and found the all process was reparative process of chronic inflammation which originated by foreign object,granulation tissue and collagenoblast multiplicitly accrementited and packed foreign object and necrotic tissue.