Preparation And Property Study Of X-ray Monitorable Poly(P-dioxanone) Radiopaque Filaments

Poly-p-dioxanone(PPDO)is a biodegradable polymeric material,which has been successfully applied to produce absorbable monofilament suture.PPDO monofilament is potential to be used in stent,inferior vena cava filter,tissue engineering scaffold,esophageal stent,tracheal stent and so on.However,PPDO only contains the elements of C,H,O without high electron cloud density elements(such as halogen or metal elements)and basically will not absorb a large number of electromagnetic spectrum.So it cannot be detected by X-ray imaging technology during or after surgery.Therefore,it is necessary to endow PPDO monofilament with radiopacity to meet medical needs.It is a simple and easy way to prepare radiopaque filaments by melt blending,which can conveniently control the upload rate of radiopaque agents.The thesis is focused on the following research items: 1.analysis of the rheological behavior and the mechanical properties of the composites;2.apparent property,thermal property and radiopacity study of the composite filaments;3.in vitro qualitative and quantitative analysis of TIBA release behavior.The main results and conclusions are as follows:(1)When the mixing temperature was 130 oC,the mixing time was 30 min,the composites with TIBA concentrations of 10 wt%(S1),20 wt%(S2),30 wt%(S3)could be drawn into continuous filaments.The apparent property study showed that TIBA had good relatively good dispersion in sample S1,S2 and S3.The results of thermal properties showed that the addition of TIBA did not affect the thermal decomposition temperature of the filaments;the crystallinity of the filaments decreased as the TIBA concentration increased.However,TIBA had a certain nucleation effect,which could accelerate the crystallization of PPDO filaments.The presence of iodine in filaments was detected by EDX.X-ray results showed that S2 and S3 had good radiopacity both in vitro and in vivo.(2)The release behavior of TIBA from S2 and S3 in vitro was studied.The release behavior of TIBA in the composite filaments was studied qualitatively.The results showed that the TIBA in the composite filaments was gradually released from the outside to the inside.DSC results showed that the crystallinity of the filaments increased after TIBA release,and the change was mostly due to the loss of TIBA during the observation period of 30 days.In vitro X-ray analysis showed that the S2 can maintain a radiopacity for 22 days,and S3 has no X-ray visibility after 22 days.(3)In order to further analyze the release rule of TIBA in vitro,the relationship between the release time and the cumulative release rate of TIBA was studied quantitatively.According to the drug release kinetics,the relationship between degradation time and cumulative TIBA release rate of the composite filaments was consistent with the first-order release kinetic.In conclusion,the PPDO radiopaque filaments can be prepared by melt blending,and the radiopacity can meet the short-term needs.But for the long-term radiopaque needs,the preparation process of radioaque filaments needs to be further improved.