ABSTRACT
AIM: A new type of unsaturated poly (ester-amide) viz maleic anhydride-phthalic anhydride-propylene glycol-neopentylene glycol-hexane diamine copolymer was prepared by melt polycondensation and characterized.METHODS: To use it as biodegradable bone fixation polymer materials, the flexural strength of unsaturated poly (ester-amide) prepared under different heat treatment conditions was measured after depth cross-linking. The degradation and hydrolysis of the polymer were investigated in phosphate buffer (0.1 mol/L, pH7.4) at 37 ℃ and in 0.1 mol/L NaOH standard solution at room temperature.RESULTS: The results obtained indicate that increasing heat treatment time or temperature can dramatically increase the flexural strength of cross-linked unsaturated poly (ester-amide). The maximum flexural strength of the cross-linked polymer containing 50 wt% of cross-linker was 123 MPa. After degradation 3 months, the flexural strength of the cross-linked polymer that contained 50 wt% of cross-linker and was heated at 195 ℃ for 18 hours could maintain as high as 114.3 MPa.Heat treatment conditions and cross-linker content play an important role to control the mass loss of the cross-linked polymer during the hydrolysis. The polymer exhibits bulk erosion property.CONCLUSION: The preliminary results obtained suggested that the copolymer might be used as bone internal fixation material.
ABSTRACT
Drug slow release in osteomyelitis treatment is an important biomedical problem, to prepare the high effect drug sustained-release bead is the sticking point. A sustained-release bead system consisting of gentamicin sulfate in biodegradable poly(dimer acid-tetradecandioic acid) copolymer [P(DA-TA), WDA: WTA= 50: 50] is prepared by melt casting which may be useful in osteomyelitis treatment. The stability at room temperature and the in vitro release profile in distilling water, in 0.9% saline buffer and in 0.1 mol/LpH7.4 PBS at 37 degrees C of the bead are determined, the drug release behavior in vitro follows the first order release kinetics and Peppas release kinetics equation. In vitro bacteriostatic activity studies demonstrated that the beads possessed desired bacteriostatic activity and lasted for 50 days for Staphylococcus aureus and Escherichia coli, which are common bacteria for infections in bone. All the above suggest that the biodegradable sustained-release beads may be a new treatment device for osteomyelitis treatment.