Influence of Crystallinity and Stereochemistry on the Enzymatic Degradation of Poly(lactide)s

Li, Suming; McCarthy, Stephen P.

doi:10.1021/ma990117b

Cited by 202 publications

(167 citation statements)

References 12 publications

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“…The mechanical strength, swelling behavior, capacity to undergo hydrolysis, and, subsequently, the biodegradation rate, are directly influenced by the crystallinity of the PLGA polymer, which depends on the type and molar ratio of the individual monomer components (lactide and glycolide) in the copolymer chain. 15,19 Lactic acid is more hydrophobic than glycolic acid and, therefore, lactide-rich PLGA copolymers are less hydrophilic, absorb less water, and subsequently, degrade more slowly.…”

Section: Properties Of Plgamentioning

confidence: 99%

Polylactide-co-glycolide nanoparticles for controlled delivery of anticancer agents

Dinarvand¹,

Sepehri²,

Manoochehri³

et al. 2011

IJN

390

265

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The effectiveness of anticancer agents may be hindered by low solubility in water, poor permeability, and high efflux from cells. Nanomaterials have been used to enable drug delivery with lower toxicity to healthy cells and enhanced drug delivery to tumor cells. Different nanoparticles have been developed using different polymers with or without surface modification to target tumor cells both passively and/or actively. Polylactide-co-glycolide (PLGA), a biodegradable polyester approved for human use, has been used extensively. Here we report on recent developments concerning PLGA nanoparticles prepared for cancer treatment. We review the methods used for the preparation and characterization of PLGA nanoparticles and their applications in the delivery of a number of active agents. Increasing experience in the field of preparation, characterization, and in vivo application of PLGA nanoparticles has provided the necessary momentum for promising future use of these agents in cancer treatment, with higher efficacy and fewer side effects.

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Section: Properties Of Plgamentioning

confidence: 99%

Polylactide-co-glycolide nanoparticles for controlled delivery of anticancer agents

Dinarvand¹,

Sepehri²,

Manoochehri³

et al. 2011

IJN

390

265

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“…Amorphous polymer chains crystallize during degradation. Crystalline polymer chains cannot diffuse and are assumed to hydrolyze ten times slower than amorphous chains [22], generating chain scission on the crystal fold surface. Water molecules are assumed abundant in time and space, and the size distribution of polymer chains is neglected.…”

Section: Numerical Modelmentioning

confidence: 99%

Effect of Laser-Induced Crystallinity Modification on Biodegradation Profile of Poly(L-Lactic Acid)

Hsu¹,

Tan²,

Yao

2013

Journal of Manufacturing Science and Engineering

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Poly(L-lactic acid) (PLLA) is of interest in drug delivery applications for its biodegradable and biocompatible properties. Polymer-controlled drug delivery relies on the release of embedded drug molecules from the polymer matrix during its degradation. PLLA degradation exhibits an induction period, during which an insignificant amount of degraded products and embedded drug can be released. Due to this induction period, drug release is initially nonlinear, a complication in drug delivery applications. PLLA degradation is a function of crystallinity, such that control over its crystallinity tailors drug release over time. In this study, the effect of laser-induced PLLA crystallinity reduction on degradation is investigated. Samples having lower surface crystallinity are shown to have higher rates of molecular weight reduction and earlier mass loss than nonlasertreated samples, as observed from gel permeation chromatography and mass change. Wide-angle X-ray diffraction measurements show that crystallinity increases with degradation. A numerical model is implemented from hydrolysis and diffusion mechanisms to investigate the effect of laser irradiation on biodegradation. Controlled laser treatment of PLLA offers a method for constant drug release through the reduction of surface crystallinity.

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“…[20][21][22] Therefore, the enzymatic degradation of amorphous region by proteinase K is anticipated to be a suitable method for the characterization of lamellar crystals in PLLA thin film. Figure 5 shows the AFM height images (A, B) and digitally enlarged images (C, D) of PLLA thin film (crystallized at 160 8C for 20 min) before and after enzymatic degradation by proteinase K at 37 8C for 2 h. Before enzymatic degradation, lamellar crystals were covered with amorphous region, and protruded about 10 nm in height from the surrounding amorphous region.…”

Section: Crystalline Morphology Of Plla Crystals Revealed By Enzymatimentioning

confidence: 99%

Crystal Growth in Poly(L‐lactide) Thin Film Revealed by in situ Atomic Force Microscopy

Kikkawa

Abe

Fujita

et al. 2003

Macro Chemistry & Physics

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Direct visualization of crystal growth in poly(L‐lactide) thin films was carried out by using a temperature‐controlled atomic force microscopy (AFM). At the initial stage of crystallization, edge‐on lamellar crystals have nucleated and elongated. Subsequently, the edge‐on lamellar crystals showed S‐shaped morphology and changed their orientation from edge‐on manner to flat‐on one. The curvature of edge‐on lamellar crystal has been discussed in terms of inclination and distortion of polymer chains in the crystal. In addition, mechanism on the formation of flat‐on crystal from edge‐on lamellae was proposed as derivative growth on the basis of in situ AFM observation of crystal growth and enzymatic degradation.

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Influence of Crystallinity and Stereochemistry on the Enzymatic Degradation of Poly(lactide)s

Cited by 202 publications

References 12 publications

Polylactide-co-glycolide nanoparticles for controlled delivery of anticancer agents

Polylactide-co-glycolide nanoparticles for controlled delivery of anticancer agents

Effect of Laser-Induced Crystallinity Modification on Biodegradation Profile of Poly(L-Lactic Acid)

Crystal Growth in Poly(L‐lactide) Thin Film Revealed by in situ Atomic Force Microscopy

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