Preparation and characterization of polymer micelles from poly(ethylene glycol)-poly(d,l-lactide) block copolymers as potential drug carrier

Yasugi, Kenji; Nagasaki, Yukio; Kato, Masaru; Kataoka, Kazunori

doi:10.1016/s0168-3659(99)00028-0

Cited by 243 publications

(167 citation statements)

References 43 publications

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“…The CMC values are in the range of 10 −5 g/ml. The CMC values reported in the literature for block copolymers composed of mmePEG or PEG and various polyesters generally range between 10 −4 and 10 −6 g/ml depending on their composition, the ratio between PEG and polyester chain length, their molecular weight (3,(27)(28)(29)(30)(31)(32)(33). The values are much lower than CMC of low molecular weight surfactants.…”

Section: Discussionmentioning

confidence: 99%

“…Generally high entrapment efficiencies could only be achieved when complex methods were used to prepare the drug loaded micelles or nanoparticles. Often the use of organic solvents and/or heat were necessary (2,3,10,(28)(29)(30)(31)(32)(33). In contrast, the mmePEG750-initiated CAP/TMC copolymers described in this paper form spontaneously a clear solution upon dispersion in water and solubilize in an easy way poorly water-soluble drugs.…”

Section: Discussionmentioning

confidence: 99%

“…Mainly biodegradable polyesters consisting of lactide (L or DL), -caprolactone, glycolide or copolymers thereof (27)(28)(29)(30)(31)(32)(33) or of amino acids (13) are described. To our knowledge, no papers dealing with micellar carriers of mmePEG-CAP/TMC copolymers exists, at the very least concerning the spontaneous formation.…”

Section: Discussionmentioning

confidence: 99%

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Biodegradable Self-Assembling PEG-Copolymer as Vehicle for Poorly Water-Soluble Drugs

Ould-Ouali

Ariën²,

Rosenblatt

et al. 2004

Pharm Res

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Purpose. To develop self-assembling systems increasing the solubility of poorly water-soluble drugs. Methods. Low molecular weight liquid biodegradable copolymers were synthesized by ring-opening polymerization using caprolactone (CAP) and trimethylenecarbonate (TMC) as monomers. Various initiators were evaluated. The emulsifying and self-assembling properties were investigated by a water titration method. The selfassembling systems were characterized for size, shape, isotropic behavior, cloud point, surface charge, and critical micellar concentration in order to optimize the polymer synthesis. Finally, the improvement of solubility of model drugs was assessed. Results. Only diblock monomethyl ether PEG-CAP/TMC copolymers synthesized with monomethyl ether polyethyleneglycol 550 to 2000 as initiator have shown self-assembling properties: upon dilution, these copolymers formed an isotropically clear solution with droplet sizes in the range of 20 to 100 nm. The hypothesis that these diblock polymers form micelles was confirmed by their low critical micellar concentration (10 −5 g/ml). The copolymers initated with mmePEG750 had a higher cloud point and better colloidal stability than those initiated with mmePEG 550. The solubility of the poorly water-soluble drugs was increased by 1 to 2 orders of magnitude. Good reproducibility was observed from batch to batch. Conclusions. The polyester diblock copolymer mmePEG750-CAP/ TMC forms spontaneously stable micelles in aqueous medium and increases the solubility of lipophilic drugs. They are very promising vehicles for the oral delivery of poorly water-soluble drugs.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Biodegradable Self-Assembling PEG-Copolymer as Vehicle for Poorly Water-Soluble Drugs

Ould-Ouali

Ariën²,

Rosenblatt

et al. 2004

Pharm Res

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“…Outer hydrophilic layer provides stable dispersion in aqueous media (which facilitates intravenous administration), while inner core can be loaded with relatively large amounts of hydrophobic photosensitizer. Therefore, block-copolymer micelles have been used as carriers of hydrophobic photosensitizer entrapped in their interior [45][46][47].…”

Section: Polymeric Micellesmentioning

confidence: 99%

Nanotechnology for biomedical applications - enhancement of photodynamic activity by nanomaterials

Ulatowska-Jarża¹,

Pucińska²,

Wysocka-Król³

et al. 2011

Bulletin of the Polish Academy of Sciences: Technical Sciences

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Abstract. Over the last two decades nanotechnology has become one of the most dynamically evolving field of research. The unique properties of nanomaterials, not disclosing at microscale, are examined and exploited to extend our understanding of the interactions taking place at atomic or molecular level. Those findings affect research in many areas, like e.g. alternative energy sources, electronics, physics and medicine. In this paper, the possibility of using nanomaterials for the enhancement of photodynamic activity, is discussed. A brief review on drug-delivery facilitating nanomaterials, regarding their characteristic features, is presented. An exemplary application of silver-doped nanomaterials for enhancement of photodynamic properties of two photosensitizers: Photolon and Protoporphyrin IX, is described. Influence of silver-doped nanomaterials addition on the fluorescence intensity of photosensitizers immobilized in silica-titania (SiO2-TiO2) sol was examined via VIS spectroscopy. Influence of sonication on the fluorescence enhancement was also investigated. It was demonstrated that the fluorescence enhancement of photosensitizers depends on the concentration of both: photosensitizer and silver-doped nanoparticles.

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“…However, such reaction may be desirable in applications such as vaccination therapies, and when enhanced uptake of exogenous compounds, such as anti-human immunodeficiency virus (HIV) drugs , is sought. Nanoparticle polymeric carriers, when their size is less than 100 nm, have a high potential for being accumulated in tumour sites, according to the enhanced permeation and retention (EPR) effect (Nishikawa et al, 1996;Yasugi et al, 1999). Hydrophilic modification, particularly by introducing poly(ethylene)glycol (PEG) by physical coating or covalent linking -a process known as pegylation -to the surface, prolongs the half-life of the carriers (Kumar, 2000;Seal et al, 2001;Diwan and Park, 2003) during circulation in blood by reducing opsonization and thus minimizing carrier clearance in organs such as liver, spleen, lung and bone marrow (Gref et al, 1994;Peracchia et al, 1997).…”

Section: Definitionmentioning

confidence: 99%

Materials in particulate form for tissue engineering. 1. Basic concepts

Silva

Ducheyne

Reis

2007

J Tissue Eng Regen Med

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For biomedical applications, materials small in size are growing in importance. In an era where 'nano' is the new trend, micro-and nano-materials are in the forefront of developments. Materials in the particulate form aim to designate systems with a reduced size, such as micro-and nanoparticles. These systems can be produced starting from a diversity of materials, of which polymers are the most used. Similarly, a multitude of methods are to produce particulate systems, and both materials and methods are critically reviewed here. Among the varied applications that materials in the particulate form can have, drug delivery systems are probably the most prominent, as these have been in the forefront of interest for biomedical applications. The basic concepts pertaining to drug delivery are summarized, and the role of polymers as drug delivery systems conclude this review. JOURNAL OF TISSUE ENGINEERING AND REGENERATIVE MEDICINE R E V I E W A R T I C L E

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Preparation and characterization of polymer micelles from poly(ethylene glycol)-poly(d,l-lactide) block copolymers as potential drug carrier

Cited by 243 publications

References 43 publications

Biodegradable Self-Assembling PEG-Copolymer as Vehicle for Poorly Water-Soluble Drugs

Biodegradable Self-Assembling PEG-Copolymer as Vehicle for Poorly Water-Soluble Drugs

Nanotechnology for biomedical applications - enhancement of photodynamic activity by nanomaterials

Materials in particulate form for tissue engineering. 1. Basic concepts

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