Improved Mathematical Model for the Hydrolytic Degradation of Aliphatic Polyesters

Well-defined, semi-degradable polyester/polymethacrylate block copolymers, based on ε-caprolactone (CL), d,l-lactide (DLLA), glycolide (GA) and N,N′-dimethylaminoethyl methacrylate (DMAEMA), were synthesized by ring-opening polymerization (ROP) and atom transfer radical polymerization. Comprehensive degradation studies of poly(ε-caprolactone)-block-poly(N,N′-dimethylaminoethyl methacrylate) (PCL-b-PDMAEMA) on hydrolytic degradation and enzymatic degradation were performed, and those results were compared with the corresponding aliphatic polyester (PCL). The solution pH did not affect the hydrolytic degradation rate of PCL (a 3% Mn loss after six weeks). The presence of a PDMAEMA component in the copolymer chain increased the hydrolysis rates and depended on the solution pH, as PCL-b-PDMAEMA degraded faster in an acidic environment (36% Mn loss determined) than in a slightly alkaline environment (27% Mn loss). Enzymatic degradation of PCL-b-PDMAEMA, poly(d,l-lactide)-block-poly(N,N′-dimethylaminoethyl methacrylate) (PLA-b-PDMAEMA) and poly(lactide-co-glycolide-co-ε-caprolactone)-block-poly(N,N′-dimethylaminoethyl methacrylate) (PLGC-b-PDMAEMA) and the corresponding aliphatic polyesters (PCL, PLA and PLGC) was performed by Novozyme 435. In enzymatic degradation, PLGC degraded almost completely after eleven days. For polyester-b-PDMAEMA copolymers, enzymatic degradation primarily involved the ester bonds in PDMAEMA side chains, and the rate of polyester degradation decreased with the increase in the chain length of PDMAEMA. Amphiphilic copolymers might be used for biomaterials with long-term or midterm applications such as nanoscale drug delivery systems with tunable degradation kinetics.

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Vinyl Copolymers with Faster Hydrolytic Degradation than Aliphatic Polyesters and Tunable Upper Critical Solution Temperatures

10.33774/chemrxiv-2021-llsn1 ◽

2021 ◽

Author(s):

Julien Nicolas ◽

Amaury Bossion ◽

Chen Zhu

Keyword(s):

Hydrolytic Degradation ◽

Aliphatic Polyesters ◽

Critical Solution Temperatures

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Studies of the Hydrolytic Degradation of Some Aliphatic Polyesters

Studies in Polymer Science - Biodegradable Plastics and Polymers ◽

10.1016/b978-0-444-81708-2.50060-9 ◽

1994 ◽

pp. 519-527 ◽

Cited By ~ 3

Author(s):

J.V. Seppälä ◽

R.M.H. Malin

Keyword(s):

Hydrolytic Degradation ◽

Aliphatic Polyesters

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D,L-polylactide degradation in biological media: experiment and model

Perspektivnye Materialy ◽

10.30791/1028-978x-2020-7-40-51 ◽

2020 ◽

pp. 40-51

Author(s):

I. V. Arutyunyan ◽

◽

P. I. Borovikov ◽

A. G. Dunaev ◽

L. I. Krotova ◽

...

Keyword(s):

Mathematical Model ◽

Stem Cells ◽

Culture Medium ◽

Molecular Mass Distribution ◽

Hydrolytic Degradation ◽

Living Cells ◽

Short Length ◽

Biological Media ◽

Polymer Sample ◽

Metabolic Products

The processes of changes in the surface morphology and internal structure, as well as the molecular mass distribution of amorphous D, L polylactides during their hydrolytic degradation in the presence of extra-germinal mesenchymal stem cells (MSCs) (ratschwart jelly umbilical cord) of the rat and their metabolic products have been studied. It was shown that the degradation of initially monolithic polymer samples in culture and conditioned media occurs almost identically. However, in a culture medium containing MSCs, this process is much more intense. This effect can be interpreted in terms of the influence of enzymes secreted by living cells, which diffuse from the surface into the polymer sample and accelerate its hydrolysis, entering into a catalytic reaction with the ether bonds of polylactide molecules. A mathematical model has been developed and verified that takes into account both non-catalytic and catalytic channels of hydrolysis, changes in the porosity of the polymer sample, diffusion of short-length oligomers, and adequately interprets the experimental results.

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A Simple Route to Aqueous Suspensions of Degradable Copolymer Nanoparticles from Radical Ring-Opening Polymerization-Induced Self-Assembly (rROPISA)

10.33774/chemrxiv-2021-4hk17 ◽

2021 ◽

Author(s):

Chen Zhu ◽

Stephanie Denis ◽

Julien Nicolas

Keyword(s):

Self Assembly ◽

Ring Opening ◽

Hydrolytic Degradation ◽

Structural Diversity ◽

Radical Ring ◽

Aliphatic Polyesters ◽

Degradable Polymer ◽

Aqueous Suspensions ◽

Research Fields ◽

Synthetic Strategy

Degradable polymer nanoparticles are almost exclusively obtained by formulation of preformed degradable polymers, such as aliphatic polyesters, thus resulting is very low nanoparticle concentrations and limited structural diversity. On the other hand, many different vinyl polymers can be obtained by polymerization in aqueous dispersed media, but their non-degradability limits their use especially in the biomedical field. Herein, we combined the best of both worlds by developing a two-step radical ring-opening copolymerization-induced self-assembly (rROPISA) process, allowing to generate aqueous suspensions of narrowly dispersed, degradable vinyl copolymer nanoparticles at 15 wt.% solid contents, containing cyclic ketene acetal (CKA) units in the nanoparticle core. This strategy relied on rROPISA in DMF, followed by a simple transfer step to water. It was successfully applied to the three main CKAs used in rROP and yielded nanoparticles of ~80–215 nm in diameter with tunable amount of CKA up to 21 mol.%. Successful incorporation of ester groups in the copolymers was demonstrated by hydrolytic degradation of both the copolymers and the nanoparticles. The nanoparticles’ cytocompatibility was then established by cell viability assays and cell morphology observation with three representative healthy cell lines. Not only this synthetic strategy could be of great potential for drug delivery applications, but it can also be beneficial to other research fields to yield more environmentally friendly materials involving the use of latexes, such as paints or coatings.

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Modelling pH-Optimized Degradation of Microgel-Functionalized Polyesters

Journal of Healthcare Engineering ◽

10.1155/2016/8125416 ◽

2016 ◽

Vol 2016 ◽

pp. 1-8

Author(s):

Lisa Bürgermeister ◽

Marcus Hermann ◽

Katalin Fehér ◽

Catalina Molano Lopez ◽

Andrij Pich ◽

...

Keyword(s):

Mathematical Model ◽

Degradation Products ◽

Degradation Process ◽

Diffusion Reaction ◽

Rate Equations ◽

Algebraic Equations ◽

Aliphatic Polyesters ◽

Acidic Degradation ◽

Ph Level ◽

Polymer Foils

We establish a novel mathematical model to describe and analyze pH levels in the vicinity of poly(N-vinylcaprolactam-co-acetoacetoxyethyl methacrylate-co-N-vinylimidazole) (VCL/AAEM/VIm) microgel-functionalized polymers during biodegradation. Biodegradable polymers, especially aliphatic polyesters (polylactide/polyglycolide/polycaprolactone homo- and copolymers), have a large range of medical applications including delivery systems, scaffolds, or stents for the treatment of cardiovascular diseases. Most of those applications are limited by the inherent drop of pH level during the degradation process. The combination of polymers with VCL/AAEM/VIm-microgels, which aims at stabilizing pH levels, is innovative and requires new mathematical models for the prediction of pH level evaluation. The mathematical model consists of a diffusion-reaction PDE system for the degradation including reaction rate equations and diffusion of acidic degradation products into the vicinity. A system of algebraic equations is coupled to the degradation model in order to describe the buffering action of the microgel. The model is validated against the experimental pH-monitored biodegradation of microgel-functionalized polymer foils and is available for the design of microgel-functionalized polymer components.

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