Biocompatible PEO-b-PCL Nanosized Micelles as Drug Carriers: Structure and Drug–Polymer Interactions

Chroni, Angeliki; Mavromoustakos, Thomas; Pispas, Stergios

doi:10.3390/nano10091872

Cited by 18 publications

(10 citation statements)

References 53 publications

(59 reference statements)

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“…The 1 H-NMR spectrum for the PMeOxz 72 -grad-PPhOxz 28 + 50% LSR nanocarriers in D 2 O in Figure 7, shows the distinct proton signals of LSR clearly (red letters), corroborating its successful loading in the polymeric nanocarriers. Notably, broader proton signals of the LSR phenyl group arise in positions 8-9 and 10-11, compared to those exhibited in previous studies utilizing different copolymers [45,46], implying stronger hydrophobic interactions between the phenyl group of PMeOxz 72 -grad-PPhOxz 28 and phenyl ring of LSR. The chemical shifts of LSR proton signals in the presence of PMeOxz 72 -grad-PPhOxz 28 nanoassemblies, PnBA 30 -b-POEGA 70 [46] and PEO-b-PCL [45] micelles are gathered in Table 5, reflecting its great molecular flexibility and the different extent of interactions with different copolymers.…”

Section: Nmr Studiescontrasting

confidence: 49%

“…Notably, broader proton signals of the LSR phenyl group arise in positions 8-9 and 10-11, compared to those exhibited in previous studies utilizing different copolymers [45,46], implying stronger hydrophobic interactions between the phenyl group of PMeOxz 72 -grad-PPhOxz 28 and phenyl ring of LSR. The chemical shifts of LSR proton signals in the presence of PMeOxz 72 -grad-PPhOxz 28 nanoassemblies, PnBA 30 -b-POEGA 70 [46] and PEO-b-PCL [45] micelles are gathered in Table 5, reflecting its great molecular flexibility and the different extent of interactions with different copolymers. The internal structure of PMeOxz 72 -grad-PPhOxz 28 GC and LSR moieties was confirmed by 2D-COSY measurements though intramolecular interaction analysis between their segments.…”

Section: Nmr Studiescontrasting

confidence: 49%

“…Nuclear magnetic resonance (NMR) spectroscopy is an alternative, not fully explored characterization technique to illuminate the design and drug encapsulation efficiency of polymeric nanocarriers, by thorough examination of the micelle structure and polymerdrug intermolecular interactions [43,44]. Our previous works underlined the importance of NMR spectroscopy, which was the instrument to prove that the level of interaction between the polymers and the drug influenced the stability, encapsulation efficiency (%EE), and drug release kinetics of the studied systems [45,46].…”

Section: Introductionmentioning

confidence: 99%

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Poly(2-oxazoline)-Based Amphiphilic Gradient Copolymers as Nanocarriers for Losartan: Insights into Drug–Polymer Interactions

2021

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The current study is focused on the development of highly stable drug nanocarriers by encapsulating losartan potassium (LSR) into an amphiphilic biocompatible poly(2-methyl-2-oxazoline)-grad-poly(2-phenyl-2-oxazoline) (PMeOxz72-grad-PPhOxz28) gradient copolymer (GC). Based on dynamic light scattering (DLS), the PMeOxz72-grad-PPhOxz28 (where the subscripts denote %wt composition of the components) GC formed micelles and aggregates of 13 nm and 96 nm in aqueous milieu. The presence of hydrophobic LSR molecules altered the structural characteristics of the GC, modulating the organization of the polymeric components and revealing the formation of hyper micellar nanostructures in addition to micelles. The 2D-NOESY experiments evidenced intermolecular interactions between the phenyl ring of LSR with the phenyl group of PPhOxz and eminent correlations between the butyl chain of LSR with the phenyl group of PPhOxz and methylene group of PMeOxz, respectively. Additionally, NMR studies as a function of temperature demonstrated that the presence of hydrophilic PMeOxz segments in the gradient core of PMeOxz72-grad-PPhOxz28 nanoassemblies induced an increased fluidity of the core matrix, especially upon heating, thus causing water penetration, resulting in increased proton mobility. Lastly, the ultrasound release profile of LSR signified that a great amount of the encapsulated LSR is tightly bound to the PMeOxz72-grad-PPhOxz28 nanoassemblies.

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Section: Nmr Studiescontrasting

confidence: 49%

Section: Nmr Studiescontrasting

confidence: 49%

Section: Introductionmentioning

confidence: 99%

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Poly(2-oxazoline)-Based Amphiphilic Gradient Copolymers as Nanocarriers for Losartan: Insights into Drug–Polymer Interactions

2021

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“…Hitherto, the examination of micelle structure and polymer–drug intermolecular interactions using nuclear magnetic resonance (NMR) spectroscopy is scarce in existing research for rational polymeric nanocarrier design and drug encapsulation [ 26 , 36 ]. According to our previous work, NMR spectroscopy proved a robust tool for the structural elucidation of the micelles and the detection of the intra- and intermolecular interactions between the copolymer and the drug [ 37 ].…”

Section: Introductionmentioning

confidence: 99%

Nano-Assemblies from Amphiphilic PnBA-b-POEGA Copolymers as Drug Nanocarriers

2021

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The focus of this study is the development of highly stable losartan potassium (LSR) polymeric nanocarriers. Two novel amphiphilic poly(n-butyl acrylate)-block-poly(oligo(ethylene glycol) methyl ether acrylate) (PnBA-b-POEGA) copolymers with different molecular weight (Mw) of PnBA are synthesized via reversible addition fragmentation chain transfer (RAFT) polymerization, followed by the encapsulation of LSR into both PnBA-b-POEGA micelles. Based on dynamic light scattering (DLS), the PnBA30-b-POEGA70 and PnBA27-b-POEGA73 (where the subscripts denote wt.% composition of the components) copolymers formed micelles of 10 nm and 24 nm in water. The LSR-loaded PnBA-b-POEGA nanocarriers presented increased size and greater mass nanostructures compared to empty micelles, implying the successful loading of LSR into the inner hydrophobic domains. A thorough NMR (nuclear magnetic resonance) characterization of the LSR-loaded PnBA-b-POEGA nanocarriers was conducted. Strong intermolecular interactions between the biphenyl ring and the butyl chain of LSR with the methylene signals of PnBA were evidenced by 2D-NOESY experiments. The highest hydrophobicity of the PnBA27-b-POEGA73 micelles contributed to an efficient encapsulation of LSR into the micelles exhibiting a greater value of %EE compared to PnBA30-b-POEGA70 + 50% LSR nanocarriers. Ultrasound release profiles of LSR signified that a great amount of the encapsulated LSR is strongly attached to both PnBA30-b-POEGA70 and PnBA27-b-POEGA73 micelles.

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“…With an additional increase in the alcohol, the diameter decreases. This leads to a smaller micellar core and more compact structure of the micelle itself, and decreased mobility of the SDS protons [ 34 ].…”

Section: Discussionmentioning

confidence: 99%

The Additive Influence of Propane-1,2-Diol on SDS Micellar Structure and Properties

et al. 2021

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Micellar systems are colloids with significant properties for pharmaceutical and food applications. They can be used to formulate thermodynamically stable mixtures to solubilize hydrophobic food-related substances. Furthermore, micellar formation is a complex process in which a variety of intermolecular interactions determine the course of formation and most important are the hydrophobic and hydrophilic interactions between surfactant–solvent and solvent–solvent. Glycols are organic compounds that belong to the group of alcohols. Among them, propane-1,2-diol (PG) is a substance commonly used as a food additive or ingredient in many cosmetic and hygiene products. The nature of the additive influences the micellar structure and properties of sodium dodecyl sulfate (SDS). When increasing the mass fraction of propane-1,2-diol in binary mixtures, the c.m.c. values decrease because propane-1,2-diol is a polar solvent, which gives it the ability to form hydrogen bonds, decreasing the cohesivity of water and reducing the dielectric constant of the aqueous phase. The values of ΔGm0 are negative in all mixed solvents according to the reduction in solvophobic interactions and increase in electrostatic interaction. With the rising concentration of cosolvent, the equilibrium between cosolvent in bulk solution and in the formed micelles is on the side of micelles, leading to the formation of micelles at a lower concentration with a small change in micellar size. According to the 1H NMR, with the addition of propylene glycol, there is a slight shift of SDS peaks towards lower ppm regions in comparison to the D2O peak. The shift is more evident with the increase in the amount of added propane-1,2-diol in comparison to the NMR spectra of pure SDS. Addition of propane-1,2-diol causes the upfield shift of the protons associated with hydrophilic groups, causing the shielding effect. This signifies that the alcohol is linked with the polar head groups of SDS due to its proximity to the SDS molecules.

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Biocompatible PEO-b-PCL Nanosized Micelles as Drug Carriers: Structure and Drug–Polymer Interactions

Cited by 18 publications

References 53 publications

Poly(2-oxazoline)-Based Amphiphilic Gradient Copolymers as Nanocarriers for Losartan: Insights into Drug–Polymer Interactions

Poly(2-oxazoline)-Based Amphiphilic Gradient Copolymers as Nanocarriers for Losartan: Insights into Drug–Polymer Interactions

Nano-Assemblies from Amphiphilic PnBA-b-POEGA Copolymers as Drug Nanocarriers

The Additive Influence of Propane-1,2-Diol on SDS Micellar Structure and Properties

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