Influence of particle size and dissolution conditions on the degradation properties of polylactide-co-glycolide particles

Dunne, Mairéad; Corrigan, Owen I.; Ramtoola, Zebunnissa

doi:10.1016/s0142-9612(00)00040-5

Cited by 397 publications

(272 citation statements)

References 40 publications

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“…The consequence was that bone formation was affected. Moreover, with more than 10 years of surgery history, it has been shown that residual crystalline particle wear debris was often present in the area of the screw and could also affect the normal bone healing (Simon et al, 1997;Dunne et al, 2000).…”

Section: Eglin and M Alini Degradable Polymeric Materials For Osteosymentioning

confidence: 99%

Degradable polymeric materials for osteosynthesis: Tutorial

Eglin

Alini²

2008

eCM

111

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This report summarizes the state of the art and recent developments and advances in the use of degradable polymers devices for osteosynthesis. The current generation of biodegradable polymeric implants for bone repair utilising designs copied from metal implants, originates from the concept that devices should be supportive and as "inert" substitute to bone tissue. Today degradable polymeric devices for osteosynthesis are successful in low or mild load bearing applications. However, the lack of carefully controlled randomized prospective trials that document their efficacy in treating a particular fracture pattern is still an issue. Then, the choice between degradable and non-degradable devices must be carefully weighed and depends on many factors such as the patient age and condition, the type of fracture, the risk of infection, etc. The improvement of the biodegradable devices mechanical properties and their degradation behaviour will have to be achieved to broaden their use. The next generation of biodegradable implants will probably see the implementation of the recent gained knowledge in cellmaterial interactions and cells therapy, with a better control of the spatial and temporal interfaces between the material and the surrounding bone tissue.

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Section: Eglin and M Alini Degradable Polymeric Materials For Osteosymentioning

confidence: 99%

Degradable polymeric materials for osteosynthesis: Tutorial

Eglin

Alini²

2008

eCM

111

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“…This was attributed to the increasing surface area to volume ratio for decreasing particle size, which enabled more efficient buffer penetration. 28 Similarly, the drug release rate was the highest for the smallest particles, due to the shorter diffusion distance for the encapsulated drug (Figure 3c).…”

Section: Mps Separation Using Hidffmentioning

confidence: 84%

“…28,29 However, most bottom-up synthesis approaches yield a wide size range of particles and it is challenging to obtain particles of well-defined sizes without additional sample preparation steps. Using PTX and cancer therapy as a model system to demonstrate enhanced drug release using sub-micrometer drug carriers, we size-fractionated PTX-loaded polydisperse MPs using HiDFF and assessed their efficacy in drug release and cancer treatment.…”

Section: Mps Separation Using Hidffmentioning

confidence: 99%

Rapid purification of sub-micrometer particles for enhanced drug release and microvesicles isolation

et al. 2017

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Efficient separation of sub-micrometer synthetic or biological components is imperative in particle-based drug delivery systems and purification of extracellular vesicles for point-of-care diagnostics. Herein, we report a novel phenomenon in spiral inertial microfluidics, in which the particle transient innermost distance (D inner ) varies with size during Dean vortices-induced migration and can be utilized for small microparticle (MP) separation; aptly termed as high-resolution Dean flow fractionation (HiDFF). The developed technology was optimized using binary bead mixtures (1-3 μm) to achieve~100-to 1000-fold enrichment of smaller particles. We demonstrated tunable size fractionation of polydispersed drug-loaded poly(lactic-co-glycolic acid) particles for enhanced drug release and anti-tumor effects. As a proof-of-concept for microvesicles studies, circulating extracellular vesicles/ MPs were isolated directly from whole blood using HiDFF. Purified MPs exhibited well-preserved surface morphology with efficient isolation within minutes as compared with multi-step centrifugation. In a cohort of type 2 diabetes mellitus subjects, we observed strong associations of immune cell-derived MPs with cardiovascular risk factors including body mass index, carotid intima-media thickness and triglyceride levels (Po0.05). Overall, HiDFF represents a key technological progress toward highthroughput, single-step purification of engineered or cell-derived MPs with the potential for quantitative MP-based health profiling. NPG Asia Materials (2017) 9, e434; doi:10.1038/am.2017.175; published online 29 September 2017 INTRODUCTIONEnabling technologies for continuous, size-based separation of submicrometer engineered or biological components are highly desirable in clinical applications, such as particle-based drug delivery systems 1 and the purification of extracellular vesicles in clinical diagnostics. 2 In microparticle fabrication, conventional 'bottom-up' self-assembly emulsification techniques yield a broad particle size distribution, which can affect the drug release kinetics and biotransport in blood. 3,4 Although well-controlled and monodisperse particles can be produced by 'top-down' approaches using specific lithographic techniques 5,6 and microfluidics, 7,8 microfabricated particles are prone to damage during mechanical harvesting, a problem further aggravated at the smaller/nanoscale level. Similarly, microfluidic synthesis of drug-loaded polymeric particles requires compatible drug/surfactant chemistry with additional steps to remove solvent prior use. Developing novel tools to achieve tunable size fractionation of polydispersed synthetic particles would enable optimal biodistribution and controlled drug release. Such technologies also facilitate physical isolation of smaller biological targets (o2 μm) including platelets, microbes and extracellular vesicles in a label-free manner for unbiased downstream analysis.

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“…2 and 3). Smaller microspheres with a higher porosity had faster polymer degradation as well as shorter diffusional paths for the released drug to enter into the release media (Dunne et al, 2000). Accordingly, Formulation 3 showed faster risperidone release compared with Formulation 2 even though these two microsphere formulations were prepared using the same solvent system (Fig.…”

Section: Discussionmentioning

confidence: 97%

“…molecular weight, copolymer ratio and crystallinity) (Park, 1995) and the drug (Miyajima et al, 1998), as well as key quality attributes (e.g. particle size, morphology, porosity, and drug loading) of the PLGA microspheres may affect in vitro drug release characteristics (Dunne et al, 2000;Ehtezazi and Washington, 2000;Luan et al, 2006;Panyam et al, 2003). Risperidone, a tertiary amine drug with a pKa of 8.18 (20°C), has been shown to catalyze PLGA hydrolysis and degradation, thus resulting in a dramatic decrease in polymer molecular weight (Fig.…”

Section: Discussionmentioning

confidence: 99%

A reproducible accelerated in vitro release testing method for PLGA microspheres

Shen

Lee

Choi

et al. 2016

International Journal of Pharmaceutics

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The objective of the present study was to develop a discriminatory and reproducible accelerated in vitro release method for long-acting PLGA microspheres with inner structure/porosity differences. Risperidone was chosen as a model drug. Qualitatively and quantitatively equivalent PLGA microspheres with different inner structure/porosity were obtained using different manufacturing processes. Physicochemical properties as well as degradation profiles of the prepared microspheres were investigated. Furthermore, in vitro release testing of the prepared risperidone microspheres was performed using the most common in vitro release methods (i.e. sample-andseparate and flow through) for this type of product. The obtained compositionally equivalent risperidone microspheres had similar drug loading but different inner structure/porosity. When microsphere particle size appeared similar, porous risperidone microspheres showed faster microsphere degradation and drug release compared with less porous microspheres. Both in vitro release methods investigated were able to differentiate risperidone microsphere formulations with differences in porosity under real-time (37°C) and accelerated (45°C) testing conditions. Notably, only the accelerated USP apparatus 4 method showed good reproducibility for highly porous risperidone microspheres. These results indicated that the accelerated USP apparatus 4 method is an appropriate fast quality control tool for long-acting PLGA microspheres (even with porous structures). Graphical Abstract*

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Influence of particle size and dissolution conditions on the degradation properties of polylactide-co-glycolide particles

Cited by 397 publications

References 40 publications

Degradable polymeric materials for osteosynthesis: Tutorial

Degradable polymeric materials for osteosynthesis: Tutorial

Rapid purification of sub-micrometer particles for enhanced drug release and microvesicles isolation

A reproducible accelerated in vitro release testing method for PLGA microspheres

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