Holmium-Loaded Poly(<scp>l</scp>-lactic Acid) Microspheres:  In Vitro Degradation Study

Zielhuis, S.W.; Nijsen, J. Frank W.; Krijger, Gerard C.; Schip, and Alfred D. van het; Hennink, Wim E.

doi:10.1021/bm060230r

Cited by 25 publications

(17 citation statements)

References 25 publications

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“…As can be observed, the release of holmium was below 0.5% after 6 months. This is comparable to the holmium release (0.7 ± 0.2%) reported for holmium loaded poly(L-lactic acid) microspheres (HoPLLAMS) in the same buffer (16). The HoPLLAMS are considered radiochemically stable and are currently under clinical investigation in a Phase I study for treatment of liver malignancies (20).…”

Section: Resultssupporting

confidence: 82%

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Radioactive Holmium Acetylacetonate Microspheres for Interstitial Microbrachytherapy: An In Vitro and In Vivo Stability Study

et al. 2011

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PurposeThe clinical application of holmium acetylacetonate microspheres (HoAcAcMS) for the intratumoral radionuclide treatment of solid malignancies requires a thorough understanding of their stability. Therefore, an in vitro and an in vivo stability study with HoAcAcMS was conducted.MethodsHoAcAcMS, before and after neutron irradiation, were incubated in a phosphate buffer at 37°C for 6 months. The in vitro release of holmium in this buffer after 6 months was 0.5%. Elemental analysis, scanning electron microscopy, infrared spectroscopy and time of flight secondary ion mass spectrometry were performed on the HoAcAcMS.ResultsAfter 4 days in buffer the acetylacetonate ligands were replaced by phosphate, without altering the particle size and surface morphology. HoAcAcMS before and after neutron irradiation were administered intratumorally in VX2 tumor-bearing rabbits. No holmium was detected in the faeces, urine, femur and blood. Histological examination of the tumor revealed clusters of intact microspheres amidst necrotic tissue after 30 days.ConclusionHoAcAcMS are stable both in vitro and in vivo and are suitable for intratumoral radionuclide treatment.

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Section: Resultssupporting

confidence: 82%

“…(16). Neutron irradiated microsphere samples (50 mg) were suspended in 100 μl of 2% Pluronic ® F68 aqueous solution and incubated in test tubes containing 5 mL isotonic phosphate buffer (116 mM, 39 mmol of NaH 2 PO 4 ·2H 2 O and 77 mmol of Na 2 HPO 4 ·2H 2 O in 1 L, pH 7.4) with 0.05% NaN 3 to prevent bacterial growth.…”

Section: Methodsmentioning

confidence: 99%

Radioactive Holmium Acetylacetonate Microspheres for Interstitial Microbrachytherapy: An In Vitro and In Vivo Stability Study

et al. 2011

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“…L/D ratio) (Athanasiou et al 1998; Waris et al 2004). In addition, thermoplastic PLA can be formed into various architectural forms including films (Auras et al 2003; Hossain et al 2012), scaffolds (Chung et al 2011; Montjovent et al 2005), fibres (Hossain et al 2014a, c; Leenslag and Pennings 1987), rods (Felfel et al 2011) and microspheres (Ehtezazi and Washington 2000; Izumikawa et al 1991; Ruan and Feng 2003; Zielhuis et al 2006). It has also been processed via solvent (Chung et al 2001) and emulsion-solvent (Hong et al 2005; Ruan and Feng 2003) evaporation processes to produce microsphere structures with varying morphologies.…”

Section: Manufacture and Characterisation Of Microspheresmentioning

confidence: 99%

“…In vitro degradation analysis over a 52-week period of holmium-loaded PLLA (Ho-PLLA) microspheres (before and after neutron or gamma irradiation) was investigated by Zielhuis et al (2006). PLLA microspheres (diameter ranging from 20 to 50 μ) were produced by dissolving PLLA in chloroform and then dispersing the solution of organic solvent into an aqueous solution of PVA (2 wt %) as presented in Fig.…”

Section: Manufacture and Characterisation Of Microspheresmentioning

confidence: 99%

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Development of microspheres for biomedical applications: a review

2014

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An overview of microspheres manufactured for use in biomedical applications based on recent literature is presented in this review. Different types of glasses (i.e. silicate, borate, and phosphates), ceramics and polymer-based microspheres (both natural and synthetic) in the form of porous , non-porous and hollow structures that are either already in use or are currently being investigated within the biomedical area are discussed. The advantages of using microspheres in applications such as drug delivery, bone tissue engineering and regeneration, absorption and desorption of substances, kinetic release of the loaded drug components are also presented. This review also reports on the preparation and characterisation methodologies used for the manufacture of these microspheres. Finally, a brief summary of the existing challenges associated with processing these microspheres which requires further research and development are presented.

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Biodegradable microparticles and fiber fabrics for sustained delivery of cisplatin to treat C6 glioma in vitro

Xie

Tan

Wang

2007

J Biomedical Materials Res

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The duration of cisplatin release from most of the drug delivery devices seemed to be shorter than 14 days except large microparticles. The objective of this study was to fabricate and characterize cisplatin-loaded PLA microparticles, PLA/PLGA (30/70) composite microparticles, and fibers as formulations for long-term sustained delivery of cisplatin to treat C6 glioma in vitro by electrospray and electrospinning techniques. Cisplatin-loaded biodegradable microparticles with particle size of around 5 microm and fiber fabrics with diameter of 0.5-1.7 microm were obtained using electrospray and electrospinning techniques. Encapsulation efficiency and in vitro release of formulations were measured by ICP-OES. The encapsulation efficiency for different samples of microparticles was approximately from 33% to 72% and the fiber fabrics had encapsulation efficiency greater than 90%. Cisplatin-loaded microparticles showed typical characteristics of cisplatin release profile: a large initial burst followed by a sustained slow release of 35 days. The composite PLA/PLGA (30/70) microparticles could reduce the initial burst release of cisplatin because of their core-shell structures. In contrast, more than 75 days sustained release could be achieved by fiber fabric formulations without large initial burst. MTT assay was used to quantify the cytotoxicity of different formulations against C6 glioma cells. Microparticle formulations had slightly higher cytotoxicity than free drug. In contrast, the cytotoxicity of fiber fabrics formulation was around 4 times higher than of the free drug based on the actual amount of drug released. The microparticle and fiber fabric formulations presented may be promising for the sustained delivery of cisplatin to eliminate the undesired side effects caused by direct injection of cisplatin solution in systemic administration.

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Holmium-Loaded Poly(l-lactic Acid) Microspheres: In Vitro Degradation Study

Cited by 25 publications

References 25 publications

Radioactive Holmium Acetylacetonate Microspheres for Interstitial Microbrachytherapy: An In Vitro and In Vivo Stability Study

Radioactive Holmium Acetylacetonate Microspheres for Interstitial Microbrachytherapy: An In Vitro and In Vivo Stability Study

Development of microspheres for biomedical applications: a review

Biodegradable microparticles and fiber fabrics for sustained delivery of cisplatin to treat C6 glioma in vitro

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