Objective:To investigate the suitable dose of drug delivery system that contained vancomycin

ceftriaxone nano-hydroxyapatite/polyamide 66（n-HA/PA66）for repair the rabbits femoral defects model. Methods:Totally 192 New Zealand white rabbits were randomly divided into two femoral defects model groups（ceftriaxone and vancomycin）. Each group had 96 rabbits and was divided into4 subgroups

each subgroup had 8 time nodes and each time node had 3 rabbits. Vancomycin ratio n-HA/PA66 was 5%

4%

3%

2% respectively

preparing in four different concentrations of vancomycin n-HA/PA66 sheet:An

Bn

Cn

Dn sheet;ceftriaxone was prepared as described above with the sheet A

*

n

B

*

n

C

*

n and D

*

n flakes. The eight sheets were implanted in the two animal models I

Ⅱ

Ⅲ

Ⅳ subgroup. Postoperative 1 d

3 d

5 d

7 d

10 d

14 d

21 d

28 d 8 time points were randomly selected for general observation and radiography. Defects part of the backbone of cancellous bone and cortical bone specimens were took and crushed;zone diameters were measured with a standard curve to calculate the concentration of each specimen antibiotics. Results:The results showed that the speed of release of two antibiotics from the drug delivery system was slow

the more high antibiotic content（5% carrier delivery system

>

4% carrier delivery system

>

3% carrier delivery system

>

2% carrier delivery system）

the higher the concentration of the antibiotic release. The content of antibiotic in different four vector delivery systems was increased on the first day

reaching more than 50% of the total concentration and then gradually declined. In vivo

release of vancomycin lasted 5%

4%

3% until the 28 days

and the presence of vancomycin in defects concentrations were greater than the MIC

and local concentrations of 2% vancomycin was below the MIC on 10 d. In vivo

5%

4%

3%

2% ceftriaxone release lasted until the 28 days and had the presence of vancomycin. Meanwhile

2% ceftriaxone on the 28 d just reached MIC

which has normal bone growth in partial defects and no fibrous capsule

and the fibrous capsule were seen in the other of different concentrations. Conclusion:Nano-hydroxyapatite/polyamide 66（n-HA/PA66）contained 3% vancomycin and n-HA/PA66 contained 2% ceftriaxone sustained release system can effectively prevent and treat the defects of infection

providing a theoretical reference for clinical treatment.