PLGA Erosion: Solubility- or Diffusion-Controlled?

Körber, Martin

doi:10.1007/s11095-010-0232-5

Cited by 57 publications

(46 citation statements)

References 20 publications

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“…To mimic physiological conditions, PLGA degradation studies are normally carried out in a pH 7.4 phosphate buffer saline media [10,[13][14][15][16][17]. However, the typical release of acidic products produced by the hydrolysis process tends to diminish the pH of the medium along the time [6], and therefore strict physiological conditions are not properly reproduced.…”

Section: Introductionmentioning

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 The degradation experiments were carried out along 40-50 days, and samples withdrawn during this period were characterized by gravimetry, electronic microscopy, and size exclusion chromatography.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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Section: Introductionmentioning

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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“…PLGA mass loss was largely dependent on the solubility of the degraded fragments, not on diffusion-controlled reactions. 21 PLGA fragments were reported to be soluble after a critical point of 15 000 Da, but are typically soluble atB1000 Da. [21][22][23] Therefore, to control the drug delivery of hydrophobic compounds, one must find mechanisms to control the rates of polyester erosion.…”

Section: Discussionmentioning

confidence: 99%

“…21 PLGA fragments were reported to be soluble after a critical point of 15 000 Da, but are typically soluble atB1000 Da. [21][22][23] Therefore, to control the drug delivery of hydrophobic compounds, one must find mechanisms to control the rates of polyester erosion. Blending of polyesters using carboxylic acid end-groups has previously been reported for microsphere formulations.…”

Section: Discussionmentioning

confidence: 99%

Tuning drug release in polyester thin films: terminal end-groups determine specific rates of additive-free controlled drug release

et al. 2013

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Modulating the drug release from polyester matrices independently of material properties would be beneficial to those designing biodegradable medical implants, such as drug delivery devices, stents and screws. However, the most common approaches use additives that often drastically alter the desired material properties. Recently, we have developed tools that allow gradient film formulations and high-throughput drug quantitation for the determination of parameter-specific correlations. We propose that modulated drug release can be obtained via additive-free mechanisms in polyesters by simply controlling polymer erosion through acidic terminal functional groups. Our results showed that drug release in poly(lactic-co-glycolic acid) (PLGA) formulations could be tuned to produce large ranges in drug release with relatively small changes in terminal acidic functional groups. For example, PLGA 53/47 thin films could be tuned to have 10-60% drug release at 14 days or 10-90% drug release at 20 days, depending on the PLGA/PLGA blend formulation and concentration of acidic terminal functional groups. A linear R-square correlation of up to 0.9 was observed for the acidic groups and percent drug release. Below a threshold of 1 part per thousand acidic groups, there was no increase in drug release, which has implications for polymer processing and film integrity.

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“…According to the characteristics of the fast release stage, the cumulative release at any time during the first 24 h could be approximated to be the upper limit (A) of the fast release stage. This release behavior could be characterized by the following equation developed based on the first-order kinetics [28] modified with an additional upper limit, A.…”

Section: In Vitro Drug Release Kineticmentioning

confidence: 99%

“…To investigate this combinational effect, several release kinetics were investigated. Drug release from biodegradable PLGA are usually characterized by the classical first-order kinetics considering the hydrolytic degradation behaviors of polymers [28], which can be expressed by equation (1) with A = 1.…”

Section: In Vitro Drug Release Kineticmentioning

confidence: 99%

Surface charge switchable and pH-responsive chitosan/polymer core-shell composite nanoparticles for drug delivery application

Huang

Tsui

Tang

et al. 2017

Composites Part B: Engineering

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PLGA Erosion: Solubility- or Diffusion-Controlled?

Abstract: The accurately calculated formation of soluble PLGA oligomers was in excellent agreement with the actual erosional mass loss of a PLGA matrix, suggesting that bulk erosion of PLGA represents a degradation-controlled dissolution process.

Cited by 57 publications

References 20 publications

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

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

Tuning drug release in polyester thin films: terminal end-groups determine specific rates of additive-free controlled drug release

Surface charge switchable and pH-responsive chitosan/polymer core-shell composite nanoparticles for drug delivery application

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