Degradation kinetics of poly(lactic-co-glycolic) acid block copolymer cast films in phosphate buffer solution as revealed by infrared and Raman spectroscopies

Vey, Elisabeth; Rodger, Caroline; Booth, Jonathan; Claybourn, Mike; Miller, Aline F.; Saiani, Alberto

doi:10.1016/j.polymdegradstab.2011.07.011

Cited by 101 publications

(95 citation statements)

References 25 publications

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“…PLGA polymer chains are composed of lactic and glycolic units linked together with different kinds of ester bonds, including G‐G, L‐G/G‐L, and L‐L combinations. Numerous studies have demonstrated that ester bonds of PLGA polymer chains are hydrolyzed at different rates after water penetration due to the difference in hydrophilicity of lactic and glycolic units . Our observations verified that G‐G bonds are the first to be cleaved during hydrolytic degradation, followed by the ester bonds L‐G or G‐L.…”

Section: Discussionsupporting

confidence: 83%

“…Numerous studies have demonstrated that ester bonds of PLGA polymer chains are hydrolyzed at different rates after water penetration due to the difference in hydrophilicity of lactic and glycolic units. 38 Our observations verified that G-G bonds are the first to be cleaved during hydrolytic degradation, followed by the ester bonds L-G or G-L. The ester bonds L-L degrade the slowest.…”

Section: Discussionsupporting

confidence: 78%

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Mapping intermediate degradation products of poly(lactic‐co‐glycolic acid) in vitro

Nemes

Guo

2017

J Biomed Mater Res

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There is widespread interest in using absorbable polymers, such as poly(lactic-co-glycolic acid) (PLGA), as components in the design and manufacture of new-generation drug eluting stents (DES). PLGA undergoes hydrolysis to progressively degrade through intermediate chemical entities to simple organic acids that are ultimately absorbed by the human body. Understanding the composition and structure of these intermediate degradation products is critical not only to elucidate polymer degradation pathways accurately, but also to assess the safety and performance of absorbable cardiovascular implants. However, analytical approaches to determining the intermediate degradation products have yet to be established and evaluated in a standard or regulatory setting. Hence, we developed a methodology using electrospray ionization mass spectrometry to qualitatively and quantitatively describe intermediate degradation products generated in vitro from two PLGA formulations commonly used in DES. Furthermore, we assessed the temporal evolution of these degradation products using time-lapse experiments. Our data demonstrated that PLGA degradation products via heterogeneous cleavage of ester bonds are modulated by multiple intrinsic and environmental factors, including polymer chemical composition, degradants solubility in water, and polymer synthesis process. We anticipate the methodologies and outcomes presented in this work will elevate the mechanistic understanding of comprehensive degradation profiles of absorbable polymeric devices, and facilitate the design and regulation of cardiovascular implants by supporting the assessments of the associated biological response to degradation products. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1129-1137, 2018.

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Section: Discussionsupporting

confidence: 83%

Section: Discussionsupporting

confidence: 78%

Mapping intermediate degradation products of poly(lactic‐co‐glycolic acid) in vitro

Nemes

Guo

2017

J Biomed Mater Res

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“…At day 33 of incubation, the implants continued their erosional processes and reached a more damaged structure; and after day 33, they became too fragile, which makes their use for SEM impossible. Some authors [26,27] suggested that the PLGA erosion typically follows a firstorder reaction kinetics. The evolution of the remaining mass is here adjusted by:…”

Section: Resultsmentioning

confidence: 99%

In vitro bulk/surface erosion pattern of PLGA implant in physiological conditions: a study based on auxiliary microsphere systems

et al. 2015

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This work investigates the degradation of PLGA implants in an aqueous medium maintained at physiological pH & 7.4. Two limiting systems are also investigated, which involve the degradation of PLGA microspheres in two different media characterized by: (i) a non-regulated pH, for emulating the autocatalyzed degradation in the implant core; and (ii) a regulated physiological pH, for emulating the uncatalyzed degradation at the implant surface. The degradation experiments were carried out along 40-50 days, and samples withdrawn during this period were characterized by gravimetry, electronic microscopy, and size exclusion chromatography. Experimental results suggest that PLGA implants are degraded according to a time-variant spatial pattern, which depends on the pH of the surrounding medium. Initially, the implants suffered a typically bulk erosion process, governed by the acidification of the implant core; and after breakage of the implant wall, the regulated physiological pH induces a surface erosion process. The two auxiliary microsphere-based experiments were useful to elucidate the degradation phenomena occurring in the PLGA implants. The evolution of the mass loss and the weight-average molecular weight along the degradation can be successfully predicted by simple mathematical models based on first-order kinetics.

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“…Raman spectra of pure PLGA and E-PLGA membranes were dominated by the noticeable band near 1,768 cm -1 ( Figure 1B), which was due to the ester linkage of PLGA. 26 The deformation band of CH 3 was observed at 1,450 cm -1 , which corresponds to the antisymmetric vibration of CH 3 from the lactic unit of PLGA. 26 Also, quite intense and definite bands were found at 1,046 cm -1 and 1,127 cm -1 for the C-CH 3 of PLGA.…”

Section: Physicochemical Characteristics Of E-plga Nanofiber Membranesmentioning

confidence: 98%

“…26 The deformation band of CH 3 was observed at 1,450 cm -1 , which corresponds to the antisymmetric vibration of CH 3 from the lactic unit of PLGA. 26 Also, quite intense and definite bands were found at 1,046 cm -1 and 1,127 cm -1 for the C-CH 3 of PLGA. In E-PLGA membranes, the characteristic bands were found near 1,640 cm -1 and 3,450 cm…”

Section: Physicochemical Characteristics Of E-plga Nanofiber Membranesmentioning

confidence: 98%

PLGA nanofiber membranes loaded with epigallocatechin-3-O-gallate are beneficial to prevention of postsurgical adhesions

Shin¹,

Yang²,

Lee³

et al. 2014

IJN

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This study concentrates on the development of biodegradable nanofiber membranes with controlled drug release to ensure reduced tissue adhesion and accelerated healing. Nanofibers of poly(lactic- co -glycolic acid) (PLGA) loaded with epigallocatechin-3- O -gallate (EGCG), the most bioactive polyphenolic compound in green tea, were electrospun. The physicochemical and biomechanical properties of EGCG-releasing PLGA (E-PLGA) nanofiber membranes were characterized by atomic force microscopy, EGCG release and degradation profiles, and tensile testing. In vitro antioxidant activity and hemocompatibility were evaluated by measuring scavenged reactive oxygen species levels and activated partial thromboplastin time, respectively. In vivo antiadhesion efficacy was examined on the rat peritonea with a surgical incision. The average fiber diameter of E-PLGA membranes was approximately 300–500 nm, which was almost similar to that of pure PLGA equivalents. E-PLGA membranes showed sustained EGCG release mediated by controlled diffusion and PLGA degradation over 28 days. EGCG did not adversely affect the tensile strength of PLGA membranes, whereas it significantly decreased the elastic modulus and increased the strain at break. E-PLGA membranes were significantly effective in both scavenging reactive oxygen species and extending activated partial thromboplastin time. Macroscopic observation after 1 week of surgical treatment revealed that the antiadhesion efficacy of E-PLGA nanofiber membranes was significantly superior to those of untreated controls and pure PLGA equivalents, which was comparable to that of a commercial tissue-adhesion barrier. In conclusion, the E-PLGA hybrid nanofiber can be exploited to craft strategies for the prevention of postsurgical adhesions.

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Degradation kinetics of poly(lactic-co-glycolic) acid block copolymer cast films in phosphate buffer solution as revealed by infrared and Raman spectroscopies

Cited by 101 publications

References 25 publications

Mapping intermediate degradation products of poly(lactic‐co‐glycolic acid) in vitro

Mapping intermediate degradation products of poly(lactic‐co‐glycolic acid) in vitro

In vitro bulk/surface erosion pattern of PLGA implant in physiological conditions: a study based on auxiliary microsphere systems

PLGA nanofiber membranes loaded with epigallocatechin-3-O-gallate are beneficial to prevention of postsurgical adhesions

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