Non-covalent interactions between poly(N-isopropylacrylamide) and small aromatic probe molecules studied by NMR spectroscopy

Szabó, Márk; Berke, Barbara; László, Krisztina; Osváth, Zsófia; Domján, Attila

doi:10.1016/j.eurpolymj.2017.03.032

Cited by 6 publications

(4 citation statements)

References 46 publications

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“…As the phase transition takes place in the temperature range of the human body, these polymers are suggested for various applications such as drug delivery [ 5 , 6 , 7 , 8 ], tissue engineering [ 9 , 10 ], self-healing coatings [ 11 ], carrier for catalysts [ 12 ], or even ion-sensitive sensors [ 13 , 14 ]. Many physical and chemical stimuli are available [ 15 ] to influence the phase transition behavior such as salts [ 16 ], surfactants [ 17 ], solvents [ 18 ], ultrasound [ 19 ], electromagnetic radiation [ 20 ], and additives [ 21 , 22 , 23 ].…”

Section: Introductionmentioning

confidence: 99%

“…The application of microgels for drug delivery purposes requires fundamental knowledge about interactions between polymeric structures and model drugs [ 39 , 40 ]. As medically relevant drugs often exhibit complex molecular structures, small aromatic model drugs are preferentially used to mimic the former [ 21 , 23 ]. Such aromatic additives shift the hydrophobic coil-to-globule transition of PNiPAM and poly( N , N -diethylacrylamide) (PDEAM) homopolymers to lower temperatures [ 41 ].…”

Section: Introductionmentioning

confidence: 99%

“…Such aromatic additives shift the hydrophobic coil-to-globule transition of PNiPAM and poly( N , N -diethylacrylamide) (PDEAM) homopolymers to lower temperatures [ 41 ]. Concerning PNiPAM homopolymers and microgels, detailed studies involved phenol [ 23 , 32 , 40 ], hydroxybenzenes [ 41 ], benzaldehydes [ 21 , 41 ], and dopamine [ 23 , 40 ], as well as indol [ 40 ] and its dervatives [ 23 ]. For example, an indole ring as a component of various biologically active natural products was shown to interact with PNiPAM only above the LCST [ 23 ], while all aromatic additives reduce the phase transition temperature.…”

Section: Introductionmentioning

confidence: 99%

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Interplay of the Influence of Crosslinker Content and Model Drugs on the Phase Transition of Thermoresponsive PNiPAM-BIS Microgels

Schlattmann

Schönhoff

2022

Gels

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The phase transition behavior of differently crosslinked poly(N-isopropylacrylamide)/N,N’-methylenebisacrylamide (PNiPAM/BIS) microgels with varying crosslinker content is investigated in presence of aromatic additives. The influence of meta-hydroxybenzaldehyde (m-HBA) and 2,4-dihydroxybenzaldehyde (2,4-DHBA), chosen as model drugs, on the volume phase transition temperature (VPTT) is analyzed by dynamic light scattering (DLS), differential scanning calorimetry (DSC), and 1H-NMR, monitoring and comparing the structural, calorimetric, and dynamic phase transition, respectively. Generally, the VPTT is found to increase with crosslinker content, accompanied by a drastic decrease of transition enthalpy. The presence of an additive generally decreases the VPTT, but with distinct differences concerning the crosslinker content. While the structural transition is most affected at lowest crosslinker content, the calorimetric and dynamic transitions are most affected for an intermediate crosslinker content. Additive uptake of the collapsed gel is largest for low crosslinked microgels and in case of large additive-induced temperature shifts. Furthermore, as temperature is successively raised, 1H NMR data, aided by spin relaxation rates, reveal an interesting uptake behavior, as the microgels act in a sponge-like fashion including a large initial uptake and a squeeze-out phase above VPTT.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Interplay of the Influence of Crosslinker Content and Model Drugs on the Phase Transition of Thermoresponsive PNiPAM-BIS Microgels

Schlattmann

Schönhoff

2022

Gels

View full text Add to dashboard Cite

show abstract

“…LMWCs are added as additives to improve the properties of the polymeric component [6,[30][31][32][33][34][35][36][37]. Consequently, polymer-LMWC blends with different practical applications have been reported: controlled drug devices [38][39][40][41][42], regenerative medicine [43], electronic devices [44], hemodialysis applications [45], etc. In addition, LMWCs have been used not only as blend components but also as blend compatibilizers [46][47][48][49].…”

Section: Introductionmentioning

confidence: 99%

Blends of Poly(vinyl Pyridine)s and Dihydric Phenols: Thermal and Infrared Spectroscopic Studies. Part V

Gatica¹,

Medina²,

Moraga³

et al. 2019

J. Chil. Chem. Soc.

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Binary blends with poly(4-vinyl pyridine) (P4VPy) 160,000 g/mol and poly(2-vinyl pyridine) (P2VPy) 159,000 g/mol as polymer components and 4,4´-thiodiphenol (TDP), 4,4´-methylendiphenol (MDP), 2,2´-biphenol (22BP) and 4,4´-biphenol (44BP) as low molecular weight compounds (LMWCs), were prepared. Miscibility between the components was analyzed by Fourier Transform Infrared Spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC). Thermogravimetric Analysis (TGA) and Scanning Electron Microscopy (SEM) were also used as complementary techniques. Hydrogen bonding formation was detected by FTIR due to the increasing of the wave number corresponding to the deformation absorption of pyridine groups in P4VPy and P2VPy. A decreasing of melting points and fusion heats of the LMWCs is observed by DSC, which shows a lower crystallinity level as the blends are richer in the polymer component as a consequence of the intermolecular interaction. A plasticizing effect is also observed by DSC when P4VPy is blended with TDP and MDP; the higher steric hindrance prevents this effect when P2VPy is blended with 22BP and 44BP. Miscible blends were obtained with a moderate trend to a higher interaction degree in blends containing P4VPy. This report is the fifth part of a series of works including polymer-LMWC blends. Variables such as molecular weight increase in P4VPy and steric hindrance in P2VPy have been comparatively analyzed with blends previously reported.

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Anomalous release of indoles from amorphous solid dispersion formed with a polymeric network

Bulátkó,

Domján,

Balterer

et al. 2024

J Therm Anal Calorim

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Amorphous solid dispersion (ASDs) is a technique used in the pharmaceutical industry to enhance the solubility, dissolution rate, and bioavailability of poorly soluble drugs. Polymeric materials, and recently polymer gels form and stabilize the amorphous structure by inhibiting the aggregation/precipitation of such drugs. In this work indole, 5-aminoindole and 5-hydroxyindole loaded poly (N-isopropylacrylamide) (PNIPA) hydrogels were studied. Swelling and uptake measurements, X-ray diffraction (XRD), liquid and solid phase nuclear magnetic spectroscopy (NMR) and high sensitivity differential scanning calorimetry (DSC) were applied to understand the drug – matrix interactions affecting the release. We confirmed that the hydrogel fostered the fine uniform distribution of the hydrophobic probe molecules and successfully prevented any crystalline or amorphous phase formation during water removal, leading to a glassy solution, a special form of ASD. Despite the limited difference between their chemical composition the probe molecules showed dissimilar drug release behavior from dried loaded gel disks. While Nuclear Overhauser Enhancement Spectroscopy (NOESY) measurements revealed a “bidental” interaction between 5-hydroxiindole and the polymer, no localized interactions were found for indole. The release of the bidentally linked derivatives is rapid and complete: they act as molecular spacers, promoting the rehydration of the chains. In contrast, part of the indole remains irreversibly trapped being confined between the chains without any orientation, shedding light on the role of the steric consequences of the interaction. Our findings also indicate that such drug delivery compositions should be treated as ternary systems (carrier + drug + liquid) already in the design stages of drug release systems.

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Non-covalent interactions between poly(N-isopropylacrylamide) and small aromatic probe molecules studied by NMR spectroscopy

Cited by 6 publications

References 46 publications

Interplay of the Influence of Crosslinker Content and Model Drugs on the Phase Transition of Thermoresponsive PNiPAM-BIS Microgels

Interplay of the Influence of Crosslinker Content and Model Drugs on the Phase Transition of Thermoresponsive PNiPAM-BIS Microgels

Blends of Poly(vinyl Pyridine)s and Dihydric Phenols: Thermal and Infrared Spectroscopic Studies. Part V

Anomalous release of indoles from amorphous solid dispersion formed with a polymeric network

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