CAJ | 학술논문

目的对高相对分子质量(4×105～5×105)的聚对二氧环己酮(PPDO)制成的可吸收线在模拟不同pH值的消化道内环境下进行体外降解行为的研究.方法取样品分别浸于3种不同pH值(1.2、7.4和8.5)的磷酸缓冲液(PBS)中,并置于37℃恒温震荡器中,分别于浸泡2、4、6、8、10、12周时取出样品,观察大体形态及色泽变化后测量湿重、干重、扫描电镜检查、红外扫描及力学性能检测等.结果聚对二氧环己酮在体外降解过程中质量损失与吸水率变化较大,第4周时失重率分别为pH=1.2组为55.91％,pH=7.4组为1.28％,pH=8.5组为2.03％,而吸水率分别为6.89％、2.44％与3.93％;未降解的PPDO具有很高的拉伸强度(112.36 MPa)与断裂伸长率(74.83％).随着降解时间的延长,强酸环境下PPDO已经丧失力学性能.第4周时,pH=7.4组拉伸强度降低至61.97 MPa,断裂伸长率为37.53％;而pH=8.5组拉伸强度为53.73 MPa,断裂伸长率为35.16％.第4周时,其力学强度也显著发生改变,但仍然＞50％,第6周时力学性能变化急剧下降,材料的外部变化显著.傅里叶红外扫描结果提示降解中未见新的化学键团等出现.结论高相对分子质量PPDO在中性及碱性环境中的降解较酸性环境慢,且具有很好的稳定性,而在强酸性环境下其降解加快,水解是PPDO的主要降解机制.提示在严重的反流性食管炎等情况下,以PPDO材料制成的食管支架可能需要加抗反流装置,以减少酸性物质对支架的降解并且减少患者的不适症状.
목적 대고상대분자질량(4×105～5×105)적취대이양배기동(PPDO)제성적가흡수선재모의불동pH치적소화도내배경하진행체외강해행위적연구.방법 취양품분별침우3충불동pH치(1.2、7.4화8.5)적린산완충액(PBS)중,병치우37℃항온진탕기중,분별우침포2、4、6、8、10、12주시취출양품,관찰대체형태급색택변화후측량습중、간중、소묘전경검사、홍외소묘급역학성능검측등.결과 취대이양배기동재체외강해과정중질량손실여흡수솔변화교대,제4주시실중솔분별위pH=1.2조위55.91％,pH=7.4조위1.28％,pH=8.5조위2.03％,이흡수솔분별위6.89％、2.44％여3.93％;미강해적PPDO구유흔고적랍신강도(112.36 MPa)여단렬신장솔(74.83％).수착강해시간적연장,강산배경하PPDO이경상실역학성능.제4주시,pH=7.4조랍신강도강저지61.97 MPa,단렬신장솔위37.53％;이pH=8.5조랍신강도위53.73 MPa,단렬신장솔위35.16％.제4주시,기역학강도야현저발생개변,단잉연＞50％,제6주시역학성능변화급극하강,재료적외부변화현저.부리협홍외소묘결과제시강해중미견신적화학건단등출현.결론 고상대분자질량PPDO재중성급감성배경중적강해교산성배경만,차구유흔호적은정성,이재강산성배경하기강해가쾌,수해시PPDO적주요강해궤제.제시재엄중적반류성식관염등정황하,이PPDO재료제성적식관지가가능수요가항반류장치,이감소산성물질대지가적강해병차감소환자적불괄증상.
Objective To study in vitro degradation behavior of absorbable suture made of poly(pdioxanone) (PPDO) with high molecular weight (Mv=4× 105～5 × 105) in simulated internal environments of the digestive tract with different pH values.Methods Absorbable suture samples were immersed in 3 kinds of phosphate buffer solution(PBS) with pH values of 1.2,7.4 and 8.5 which were put into a shaker at constant 37 ℃C.Samples were retrieved at 2,4,6,8,10,12 weeks after immersion for gross observation of their morphology and color change followed by measurement of their wet and dry weight,scanning electron microscopy,infrared scanning and mechanical tests.Results Great mass loss and water absorption change were observed during the in vitro degradation of PPDO.At 4 weeks,the mass loss rate and water absorption rate were respectively 55.91％ and 6.89％ in pH=1.2 group,1.28％ and 2.44％ in pH=7.4 group and 2.03％ and 3.93％ in pH=8.5 group.The initial PPDO had a high tensile strength (112.36 MPa) and a high elongation at break (74.83％).PPDO lost its mechanical properties in strong acid environments as the degradation progressed.At 4 weeks,the tensile strength of pH=7.4 group reduced to 61.97％ and the elongation at break to 37.53％； the tensile strength of pH=8.5 group reduced to 53.73％ and the elongation at break to 35.16％.At 4 weeks,its mechanical strength changed significantly,but still ＞50％,but at 6 weeks its mechanical strength decreased sharply and radical external changes were observed.Fourier transform infrared scanning showed no new bond groups during degradation.Conclusions The high molecular weight PPDO degrades slowly and has good stability in neutral and alkaline conditions but faster in acidic conditions,indicating hydrolysis is its degradation mechanism.Therefore,in cases of severe reflux esophagitis,PPDO esophageal stents may need an additional anti-reflux device to reduce the degradation by acidic substances and alleviate symptoms of the patients.