Improved biocompatibility of poly(vinylpyrrolidone)-graft-poly(2-dimethylaminoethyl methacrylate)/DNA complexes by coating with bovine serum albumin

Bovine serum albumin(BSA) was utilized to assemble with the binary complexes of poly(vinylpyrrolidone)-graft-poly(2- dimethylaminoethyl methacrylate)(PVP-g-PDMAEMA)/DNA formed by layer-by-layer electrostatic interactions to screen the residual surface positive charges of complexes.The coating of BSA was able to decrease the zeta potential of binary complexes nearly to electroneutrality without interfering with DNA condensation ability.The ternary complexes of BSA/PVP-g-PDMAEMA/ DNA demonstrated lower cytotoxicity compared with the binary complexes and also maintained high gene transfection efficiency in HepG2 cells.     

Self-aggregated nanoparticles from methoxy poly(ethylene glycol)-modified chitosan: synthesis; characterization; aggregation and methotrexate release in vitro

Methoxy poly(ethylene glycol)-grafted-chitosan (mPEG-g-CS) conjugates were synthesized by formaldehyde linking method and characterized by Fourier transform infrared (FT-IR) and proton nuclear magnetic resonance (¹H-NMR). The degree of substitution (DS) of methoxy poly (ethylene glycol) (mPEG) in the mPEG-g-CS molecules determined by ¹H-NMR ranged from 19% to 42%. The critical aggregation concentration (CAC) was determined by fluorescence spectroscopy using pyrene as fluorescence probe and its value was 0.07 mg/mL in water. mPEG-g-CS formed monodisperse self-aggregated nanoparticles with a roughly spherical shape and a mean diameter of 261.9 nm were prepared by the dialysis method. mPEG-g-CS self-aggregated nanoparticles were used as carriers of poorly water-soluble anticancer drug methotrexate (MTX). MTX was physically entrapped inside mPEG-g-CS self-aggregated nanoparticles by dialysis method and the characteristics of MTX-loaded mPEG-g-CS self-aggregated nanoparticles were analyzed using dynamic laser light scattering (DLLS), transmission electron microscopy (TEM). Moreover, in vitro release behavior of MTX was also investigated and the results showed that MTX was continuously released more than 50% in 48 h.     

A tumor pH-responsive complex: carboxyl-modified hyperbranched polyether and cis-dichlorodiammineplatinum(II)

To realize the pH-targeting delivery of antitumor drug cis-dichlorodiammineplatinum(II) (cisplatin, CDDP), a tumor pH-responsive polymer-platinum(II) complex (Suc-HPMHO-CDDP) from carboxyl-modified hyperbranched polyether (Suc-HPMHO) and cisplatin was designed and prepared. Because of the existence of hydrophobic core and ionization of surface carboxylic acid, Suc-HPMHO showed reversible pH-response in aqueous solution, and its responding pH value could be readily adjusted by only changing the degree of carboxylation of Suc-HPMHO. With plenty of terminal carboxyl groups, Suc-HPMHO could form the complex with CDDP by substituting the chloride ions with carboxyls. Methyl tetrazolium (MTT) assay showed that Suc-HPMHO had low cytotoxicity, while Suc-HPMHO-CDDP complex presented a similar antitumor effect with the free CDDP. Under the tumor acidic pH (pH(e)), Suc-HPMHO-CDDP complex deposited around/in cells because of its pH-response. Therefore, the pH-targeting of Suc-HPMHO-CDDP complex to tumor tissue could be realized. All of these results show that the tumor pH-responsive Suc-HPMHO-CDDP complex is a potential pH-targeting drug delivery system in cancer therapy.     

Dendritic polymers based on poly(ethylene glycol) -co- poly(glycolic acid) -co- methacrylate and 2.0 G -polyamidoamine- metharylamide: Design, characterization, and in vitro degradation, and drug release properties

In this paper, the properties of the complete degradation process of newly synthesized multi-block 2.0 G-polyamidoamine-double bond (PAMAM-DB) and resoluble poly (ethylene glycol) -co- poly (glycolic acid) -co- methacryloyl chloride (PEG-co-PGA-co-DB, 4KG5-DB) macromonomers were reported. Rectangular shaped samples were prepared by crosslinking the components using both chemical and photo initiators and exposure to UV light. The aims of the study were to examine the effects of the vitro degradation and drug delivery of the crosslinking group on the properties of photocrosslinked hydrogels. The experimental variable was PAMAM-DB: 4KG5-DB ratio. The effects of this variable on local PH, water uptake, mass loss, and drug release were explored. Polymers were characterized by ¹H NMR, ¹³C NMR, FT-IR, and SEM. Our study revealed that polymers with 40%, 50%, 60% 4KG5-DB (mass fraction) showed more excellent mechanical properties, 40% also showed outstanding vitro degradation properties. In vitro drug release, however, 60% drug released mechanism seemed to approach the Fickian diffusion and possessed more excellent drug release properties compared with formulation 40% and 50%. In general, an increase ratio of 4KG5-DB led to a higher density of tree-like polymer which resulted in slower of degradation and drug release. Incorporation of 4KG5-DB into the polymer was critical for maintaining integrity and increasing hydrophilicity during degradation. These results obtained suggest that this system could be potential as a material for bone replacement and controlled delivery of drugs.     

A sol-gel derived pH-responsive bovine serum albumin molecularly imprinted poly(ionic liquids) on the surface of multiwall carbon nanotubes

A pH-responsive surface molecularly imprinted poly(ionic liquids) (MIPILs) was prepared on the surface of multiwall carbon nanotubes (MWCNTs) by a sol-gel technique. The material was synthesized using a 3-aminopropyl triethoxysilane modified multiwall carbon nanotube (MWCNT-APTES) as the substrate, bovine serum albumin (BSA) as the template molecule, an alkoxy-functionalized IL 1-(3-trimethoxysilyl propyl)-3-methyl imidazolium chloride ([TMSPMIM]Cl) as both the functional monomer and the sol-gel catalyst, and tetraethoxysilane (TEOS) as the crosslinking agent. The molecular interaction between BSA and [TMSPMIM]Cl was quantitatively evaluated by UV–vis spectroscopy prior to polymerization so as to identify an optimal template/monomer ratio and the most suitable pH value for the preparation of the MWCNTs@BSA-MIPILs. This strategy was found to be effective to overcome the problems of trial-and-error protocol in molecular imprinting. The optimum synthesis conditions were as follows: template/monomer ratio 7:20, crosslinking agent content 2.0–2.5 mL, temperature 4 °C and pH 8.9 Tris–HCl buffer. The influence of incubation pH on adsorption was also studied. The result showed that the imprinting effect and selectivity improved significantly with increasing incubation pH from 7.7 to 9.9. This is mainly because the non-specific binding from electrostatic and hydrogen bonding interactions decreased greatly with the increase of pH value, which made the specific binding affinity from shape selectivity strengthened instead. The polymers synthesized under the optimal conditions were then characterized by BET surface area measurement, FTIR, thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The adsorption capacity, imprinting effect, selective recognition and reusability were also evaluated. The as-prepared MWCNTs@BSA-MIPILs were also found to have a number of advantages including high surface area (134.2 m² g⁻¹), high adsorption capacity (55.52 mg g⁻¹), excellent imprinting effect (imprinting factor of up to 5.84), strong selectivity (selectivity factor of 2.61 and 5.63 for human serum albumin and bovine hemoglobin, respectively), and good reusability.     

Synthesis of degradable functional poly(ethylene glycol) analogs as versatile drug delivery carriers

Poly(ethylene glycol) (PEG) is widely used as a water soluble carrier for polymer-drug conjugates. Herein, we report degradable linear PEG analogs (DPEGs) carrying multifunctional groups. The DPEGs were synthesized by a Michael addition based condensation polymerization of dithiols and PEG diacrylates (PEGDA) or dimethacrylates (PEGDMA). They were stable at pH 7.4 but quickly degraded at pH 6.0 and 5.0. Thus, DPEGs could be used as drug carriers without concern for their retention in the body. DPEGs could be made to carry such functional groups as terminal thiol or (meth)acrylate and pendant hydroxyl groups. The functional groups were used for conjugation of drugs and targeting groups. This new type of PEG analog will be useful for drug delivery and the PEGylation of biomolecules and colloidal particles.     

Complexation between poly(methacrylic) and poly(acrylic) acids and star-shaped poly(ethylene glycol) based on pyrogallol

Complex formation between polymethacrylic (PMAA) and polyacrylic acids, and star-shaped poly(ethylene glycol) prepared by ethoxylation of pyrogallol (Pyr–PEG) has been studied viscometrically and by potentiometric titration in water solution. The competitive ability of Pyr–PEG and of the derivatives of the ethoxylation of phenol and hydroquinone in complex formation with PMAA has been compared by UV spectroscopy. Pyr–PEG turns out to be the weakest competitor because of its chemical structure. © 1996 John Wiley & Sons, Inc.     

Y‐shaped poly(ethylene glycol) and poly(trimethylene carbonate) amphiphilic copolymer: Synthesis and for drug delivery

New Y‐shaped (AB₂‐type) amphiphilic copolymers of poly(ethylene glycol) (PEG) with poly(trimethylene carbonate) (PTMC), PEG‐b‐(PTMC)₂, were successfully synthesized by the ring‐opening polymerization (ROP) of TMC with bishydroxy‐modified monomethoxy‐PEG (mPEG). First, a bishydroxy functional ROP initiator was synthesized by esterification of acryloyl bromide with mPEG, followed by Michael addition using excess diethanolamine. A series of Y‐shaped amphiphilic PEG‐(PTMC)₂ block copolymers were obtained via ROP of TMC using this PEG with bishydroxyl end groups as macroinitiator and ZnEt₂ as catalyst. The amphiphilic block copolymers with different compositions were characterized by gel permeation chromatography (GPC) and ¹H NMR, and their molecular weight was measured by GPC. The results showed that the molecular weight of Y‐shaped copolymers increased with the increase of the molar ratio of TMC to mPEG‐(OH)₂ initiator in feed while the PEG chain length was kept constant. The Y‐shaped copolymer mPEG‐(PTMC)₂ could self‐assemble into micelles in aqueous medium and the critical micelle concentration values of the micelles decrease with increase in hydrophobic PTMC block length of mPEG‐(PTMC)₂. The in vitro cytotoxicity and controlled drug release properties of the Y‐shaped amphiphilic block copolymers were also investigated. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 8131–8140, 2008     

Methoxy poly(ethylene glycol)‐b‐poly(octadecanoic anhydride)‐b‐methoxy poly(ethylene glycol) amphiphilic triblock copolymer nanoparticles as delivery vehicles for paclitaxel

A series of amphiphilic triblock copolymers, methoxy poly(ethylene glycol)‐b‐poly(octadecanoic anhydride)‐b‐methoxy poly(ethylene glycol) (mPEG‐b‐POA‐b‐mPEG), were prepared via melt polycondensation of methoxy poly(ethylene glycol) (mPEG) and poly(octadecanoic anhydride) (POA). mPEG‐b‐POA‐b‐mPEG were characterized by FTIR, ¹H‐NMR, GPC, DSC, and XRD. Drug‐loaded mPEG‐b‐POA‐b‐mPEG nanoparticles (NPs) with spherical morphology and narrow size polydispersity index were prepared by nanoprecipitation technique with paclitaxel as the model drug. In vitro release behaviors of drug‐loaded NPs present that the biphasic process and the release mechanism of each phase are zero order drug releases. According to this study, mPEG‐b‐POA‐b‐mPEG NPs could serve as suitable delivery agents for paclitaxel and other hydrophobic drugs. Copyright © 2009 John Wiley & Sons, Ltd.     

Poly(ethylene glycol)/poly(ethyl cyanoacrylate) amphiphilic triblock copolymer nanoparticles as delivery vehicles for dexamethasone

Amphiphilic triblock copolymers, poly(ethyl cyanoacrylate)‐b‐poly(ethylene glycol)‐b‐poly(ethyl cyanoacrylate) (PECA‐b‐PEG‐b‐PECA), were synthesized via oxyanion‐initiated polymerization with sodium alcoholate‐terminated PEG as macroinitiator. PECA‐b‐PEG‐b‐PECA were characterized by gel permeation chromatography system, ¹H NMR and FTIR. The results indicate that the copolymerization is well controlled with narrow molecular weight distribution. The dexamethasone (DXM)‐loaded PECA‐b‐PEG‐b‐PECA nanoparticles (NPs) were prepared by nanoprecipitation technique and then characterized by Laser Particle Size Analyzer, ¹H NMR and transmission electron microscopy. The drug‐loaded PECA‐b‐PEG‐b‐PECA NPs are of spherical shape with average size of less than 100 nm. The drug‐loaded amount (DLA) and encapsulation efficiency of DLNPs were investigated by HPLC. The results show that DXM can be effectively incorporated into PECA‐b‐PEG‐b‐PECA NPs, which provides an optional delivery system for DXM and other hydrophobic drugs. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7809–7815, 2008     

Poly(ethylene glycol)–polyethyleneimine NanoGel™ particles: novel drug delivery systems for antisense oligonucleotides

A novel type of drug delivery system, termed NanoGel™ is proposed. NanoGel™ represent particles of a hydrophilic polymer network that were synthesized by cross-linking of polyethyleneimine (PEI) and carbonyldiimidazole-activated poly(ethylene glycol) (PEG) using emulsification/solvent evaporation technique. The resulting NanoGel™ was fractionated by gel-permeation chromatography. A major fraction with an average particle size of 120 nm was used in further experiments. Antisense phosphorothioate oligonucleotides (SODN) specific to human mdr1 gene were incorporated in these NanoGel™ particles. Loading of NanoGel™ particles with SODN resulted in reduction of the particle effective diameter to 80 nm and decreased zeta-potential due to neutralization of the charge of PEI chains by SODN. Accumulation of SODN incorporated in NanoGel™ particles in multidrug resistant (MDR) human oral epidermoid carcinoma cells (KBv) was significantly increased compared to the free SODN. Furthermore, efficient transport of SODN-loaded NanoGel™ particles across polarized monolayers of human intestinal epithelial cells (Caco-2) was demonstrated. Finally, antisense SODNs incorporated in NanoGel™ particles were found to effectively inhibit expression of P-glycoprotein (P-gp) efflux pump in MDR cell lines.     

α-环糊精/聚乙二醇自组装超分子纳米药物载体

研究了一种新型超分子纳米药物载体的制备方法及其药物释放性能. 将α-环糊精(α-CD)穿入肉桂酸改性的PEG分子链形成包含复合物(inclusion complex, IC), 通过超分子自组装成为纳米粒子. 将抗肿瘤药物阿霉素负载到纳米粒子中, 研究药物释放行为及其对肿瘤细胞的抑制效果. 以核磁共振(1H NMR)、X射线衍射(XRD)、紫外吸收光谱(UV)、动态光散射(DLS)、扫描电镜(SEM)、透射电镜(TEM)和原子力显微镜(AFM)表征了纳米粒子的结构和形貌, 用激光共聚焦显微镜(Confocal)研究了载药纳米粒子在细胞内的分布及其对肿瘤细胞的抑制效果. 结果显示超分子纳米粒子具有很好的生物相容性和药物缓释作用, 载药纳米粒子对肿瘤细胞具有很好的杀伤效果.     

Thermo-responsive block copolymers based on linear-type poly(ethylene glycol): Tunable LCST within the physiological range

Thermo-responsive block copolymers poly（ethylene glycol）-block-poly（N-acryloyl-2,2-dimethyl-1,3-oxazolidine）, PEG-b-PADMO,based on linear PEG were prepared via a versatile reversible addition-fragmentation chain transfer（RAFT） polymerization.PEG₂₂（M_w = 1000） was used as the hydrophilic component,whose dehydration was the main driving force for the phase transition of these copolymers,as demonstrated by the ¹H-NMR spectra.Their lower critical solution temperatures（LCSTs） could be tuned in the range of 20℃to 35℃,by adjusting the degree of polymerization（DP） of PADMO between 14-27.Furthermore,a sharp phase transition at ca.33℃,close to the physiological temperature with minimal hysteresis,was observed for the PEG₂₂-b-PADMO₁₄ copolymer.Moreover,excellent reversibility and reproducibility were displayed for the same copolymer over 10 cycles of repeated temperature change between 25℃（below the LCST） and 40℃（above the LCST）.     

Preparation, characterization and application of pyrene-loaded methoxy poly(ethylene glycol)–poly(lactic acid) copolymer nanoparticles

Pyrene-loaded biodegradable polymer nanoparticles were prepared by incorporating pyrene into the polymer nanoparticles formulated from amphiphilic diblock copolymer, methoxy poly(ethylene glycol)–poly(lactic acid) (MePEG–PLA). Their morphological structure and physical properties were characterized by nuclear magnetic resonance (NMR), dynamic light scattering, fluorescence spectroscopy, transmission electronic microscopy and zeta potential measurements. Further, MePEG–PLA nanoparticles containing pyrene as fluorescent marker were administered intranasally to rats, and the distribution of nanoparticles in the nasal mucosa and the olfactory bulb were visualized by fluorescence microscopy. NMR results confirmed that MePEG–PLA copolymer can form nanoparticles in water, and hydrophilic PEG chains were located on the surface of the nanoparticles. The particle size, zeta potential and pyrene loading efficiency of MePEG–PLA nanoparticles were dependent on the PLA block content in the copolymer. Following nasal administration, the absorption of nanoparticles across the epithelium was rapid, with fluorescence observed in the olfactory bulb at 5 min, and a higher level of fluorescence persisted in the olfactory mucosa than that in the respiratory mucosa. These results show that pyrene could serve as a useful fluorescence probe for incorporation into polymer nanoparticles to study tissue distribution and MePEG–PLA nanoparticles might have a great potential as carriers of hydrophobic drugs.     

Synthesis of poly(ethylene glycol)/polypeptide/poly(D,L‐lactide) copolymers and their nanoparticles

Core‐shell structured nanoparticles of poly(ethylene glycol) (PEG)/polypeptide/poly(D ,L ‐lactide) (PLA) copolymers were prepared and their properties were investigated. The copolymers had a poly(L ‐serine) or poly(L ‐phenylalanine) block as a linker between a hydrophilic PEG and a hydrophobic PLA unit. They formed core‐shell structured nanoparticles, where the polypeptide block resided at the interface between a hydrophilic PEG shell and a hydrophobic PLA core. In the synthesis, poly(ethylene glycol)‐b‐poly(L ‐serine) (PEG‐PSER) was prepared by ring opening polymerization of N‐carboxyanhydride of O‐(tert‐butyl)‐L ‐serine and subsequent removal of tert‐butyl groups. Poly(ethylene glycol)‐b‐poly(L ‐phenylalanine) (PEG‐PPA) was obtained by ring opening polymerization of N‐carboxyanhydride of L ‐phenylalanine. Methoxy‐poly(ethylene glycol)‐amine with a MW of 5000 was used as an initiator for both polymerizations. The polymerization of D ,L ‐lactide by initiation with PEG‐PSER and PEG‐PPA produced a comb‐like copolymer, poly(ethylene glycol)‐b‐[poly(L ‐serine)‐g‐poly(D ,L ‐lactide)] (PEG‐PSER‐PLA) and a linear copolymer, poly(ethylene glycol)‐b‐poly(L ‐phenylalanine)‐b‐poly(D ,L ‐lactide) (PEG‐PPA‐PLA), respectively. The nanoparticles obtained from PEG‐PPA‐PLA showed a negative zeta potential value of ?16.6 mV, while those of PEG‐PSER‐PLA exhibited a positive value of about 19.3 mV. In pH 7.0 phosphate buffer solution at 36 °C, the nanoparticles of PEG/polypeptide/PLA copolymers showed much better stability than those of a linear PEG‐PLA copolymer having a comparable molecular weight. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Syntheses of amphiphilic biodegradable copolymers of poly(ethyl ethylene phosphate) and poly(3-hydroxybutyrate) for drug delivery

Biodegradable and amphiphilic triblock copolymers poly(ethyl ethylene phosphate)-poly(3-hydroxy-butyrate)-poly(ethyl ethylene phosphate) (PEEP-b-PHB-b-PEEP) have been successfully synthesized through ring-opening polymerization. The structures are confirmed by gel permeation chromatography and NMR analyses. Crystallization investigated by X-ray diffraction reveals that the block copolymer with higher content of poly(ethyl ethylene phosphate) (PEEP) is more amorphous, showing decreased crystallizability. The obtained copolymers self-assemble into biodegradable nanoparticles with a core-shell micellar structure in aqueous solution, verified by the probe-based fluorescence measurements and transmission electronic microscopy (TEM) observation. The hydrophobic poly(3-hydroxybutyrate) (PHB) block serves as the core of the micelles and the micelles are stabilized by the hydrophilic PEEP block. The size and size distribution are related to the compositions of the copolymers. Paclitaxel (PTX) has been encapsulated into the micelles as a model drug and a sustained drug release from the micelles is observed. MTT assay also demonstrates that the block copolymers are biocompatible, rendering these copolymers attractive for drug delivery. Supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No.20060358036)     

Self-aggregated nanoparticles of cholesterol-modified glycol chitosan conjugate: Preparation, characterization, and preliminary assessment as a new drug delivery carrier

Cholesterol-modified glycol chitosan (CHGC) conjugate was synthesized and characterized by FTIR and ¹H NMR. The degree of substitution (DS) was 6.7 cholesterol groups per 100 sugar residues of glycol chitosan. CHGC formed self-aggregated nanoparticles with a roughly spherical shape and a mean diameter of 228 nm by probe sonication in aqueous medium. The physicochemical properties of the self-aggregated nanoparticles were studied using dynamic light scattering (DLS), transmission electron microscopy (TEM) and fluorescence spectroscopy. The critical aggregation concentration (CAC) of self-aggregated nanoparticles in aqueous solution was 0.1223 mg/mL. Indomethacin (IND), as a model drug, was physically entrapped into the CHGC nanoparticles by dialysis method. The characteristics of IND-loaded CHGC (IND-CHGC) nanoparticles was analyzed using DLS, TEM and high performance liquid chromatography (HPLC). The IND-CHGC nanoparticles were almost spherical in shape and their size increased from 275 to 384 nm with the IND-loading content increasing from 7.14% to 16.2%. The in vitro release behavior of IND from CHGC nanoparticles was studied by a dialysis method in phosphate buffered saline (PBS, pH 7.4). IND was released in a biphasic way. The initial rapid release in 2 h and slower release for up to 12 h were observed. The results indicated that CHGC nanoparticles had a potential as a drug delivery carrier.     

Interaction of pyrene-end-capped poly(ethylene oxide) with bovine serum albumin and human serum albumin in aqueous buffer medium: a fluorometric study

The photophysical behavior of a hydrophobically tailored water-soluble polymer, pyrene-end-capped poly(ethylene oxide) (PYPY), has been studied in aqueous buffered bovine serum albumin (BSA) and human serum albumin (HSA) media. In buffered aqueous solution the polymer shows dual emission corresponding to the monomer and the excimer of pyrene moiety. The relative intensity of the monomer to the excimer emission shows interesting variation with the addition of BSA and HSA and is indicative of significant interaction of these albumin proteins with the polymer. The binding interaction has been shown to have a prominent role on the steady state fluorescence anisotropy of the two emission bands. Attempt has been made to determine the micropolarities of the protein microenvironments from a comparison of the variation of the monomer to excimer relative fluorescence intensities of the probe in water–dioxane mixtures with varying composition.     

Doublestimuli-responsive degradable hydrogels for drug delivery: Interpenetrating polymer networks composed of oligopeptide-terminated poly(ethylene glycol) and dextran

Biodegradable hydrogels composed of oligopeptide-terminated poly(ethylene glycol) (PEG) and dextran with interpenetrating polymer network (IPN) structure were proposed as a novel substrate for multistimuli-responsive drug delivery. IPN-structured hydrogels were synthesized by sequential crosslinking reactions of N-methacryloyl-glycilglycilglycil-terminated PEG and dextran. In vitro degradation of the IPN-structured hydrogels was examined using papain and dextranase as model enzymes for hydrolyzing the oligopeptide and the dextran. Specific degradation in the presence of papain and dextranase was observed in the IPN-structured hydrogel with a particular composition of PEG and dextran, whereas this hydrogel was not degraded by one of the two enzymes.     

Poly(ethylene oxide)-poly(styrene oxide)-poly(ethylene oxide) copolymers: Micellization, drug solubilization, and gelling features

Two new poly(ethylene oxide)-poly(styrene oxide) triblock copolymers (PEO-PSO-PEO) with optimized block lengths selected on the basis of previous studies were synthesized with the aim of achieving a maximal solubilization ability and a suitable sustained release, while keeping very low material expense and excellent aqueous copolymer solubility. The self-assembling and gelling properties of these copolymers were characterized by means of light scattering, fluorescence spectroscopy, transmission electron microscopy, and rheometry. Both copolymers formed spherical micelles (12-14 nm) at very low concentrations. At larger concentration (>25 wt%), copolymer solutions showed a rich phase behavior, with the appearance of two types of rheologically active (more viscous) fluids and of physical gels depending on solution temperature and concentration. The copolymer behaved notably different despite their relatively similar block lengths. The ability of the polymeric micellar solutions to solubilize the antifungal drug griseofulvin was evaluated and compared to that reported for other structurally-related block copolymers. Drug solubilization values up to 55 mg g⁻¹ were achieved, which are greater than those obtained by previously analyzed poly(ethylene oxide)-poly(styrene oxide), poly(ethylene oxide)-poly(butylene oxide), and poly(ethylene oxide)-poly(propylene oxide) block copolymers. The results indicate that the selected SO/EO ratio and copolymer block lengths were optimal for simultaneously achieving low critical micelle concentrations (cmc) values and large drug encapsulation ability. The amount of drug released from the polymeric micelles was larger at pH 7.4 than at acidic conditions, although still sustained over 1 day.