Radical transfer reactions in γ-irradiated sulphur-containing vinylpolymers

Mönig, H.; Ringsdorf, Helmut; Špirk, E.

doi:10.1016/0020-7055(73)90029-6

Cited by 5 publications

(2 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Poly(vinyl mercaptan) and its copolymer with vinylpyrrolidone were extensively studied by ESR spectroscopy by M6nig et al 1522,1524). Poly(vinyl mercaptan) and its copolymer with vinylpyrrolidone were extensively studied by ESR spectroscopy by M6nig et al 1522,1524).…”

Section: Sulphur-containing Polymersmentioning

confidence: 99%

ESR Spectroscopy in Polymer Research

Rånby¹,

Rabek²

1977

Polymers Properties and Applications

295

118

View full text Add to dashboard Cite

Section: Sulphur-containing Polymersmentioning

confidence: 99%

ESR Spectroscopy in Polymer Research

Rånby¹,

Rabek²

1977

Polymers Properties and Applications

295

118

View full text Add to dashboard Cite

“… 46 , 47 As shown in Figure 2 b–f of radiation doses from 10 up to 50 kGy, there are anisotropic signals between g // and g ⊥ due to the existence of the hyperfine interaction. Figure 2 b shows the asymmetric triplet-line spectrum for (S-10); the conclusion is that an unpaired electron interacts with one corresponding proton at the Cα atom of the polymer chain 48 or it could be attributed to proxy radicals. 49 In Figure 2 c,d, no alteration of the triplet-line spectrum can be observed.…”

Section: Resultsmentioning

confidence: 99%

Improvement of In Vitro Dissolution of the Poor Water-Soluble Amlodipine Drug by Solid Dispersion with Irradiated Polyvinylpyrrolidone

et al. 2020

View full text Add to dashboard Cite

The aim of this study was to increase both the rates of dissolution and bioavailability of the amlodipine (Amlo) drug. Due to the low cost, high solubility, and amorphous state, polyvinylpyrrolidone (PVP) has been used as a drug carrier in the solid dispersion process. Through applying an irradiation technique, powder of (PVP) is irradiated with six 0–50 kGy irradiation doses. The six irradiated (PVP) samples were characterized using gel permeation chromatography, electron spin resonance, and Fourier transform infrared (FT-IR) spectroscopy. The formulation of six (PVP/Amlo) samples at a ratio of 2:1 wt/wt were characterized using FT-IR spectroscopy and X-ray powder diffraction. In vitro dissolution of (Amlo) drug was assessed in a water solvent at pH 1.2 and pH 7. Results demonstrated that there is a change in the physicochemical properties of irradiated (PVP). FT-IR confirmed that there is an intermolecular H bond between the (Amlo) drug and (PVP) polymer. XRD confirmed that (PVP) changes the crystalline (Amlo) to amorphous amlodipine. Irradiated (PVP) at a dose of 20 kGy released approximately 89% from 40 mg of (Amlo) in 60 s. The in vitro rate of amlodipine dissolution depends on the drug–polymer intermolecular H bond. The rate of (Amlo) dissolution is increased due to the drug–drug intramolecular hydrogen bonding replaced with the drug–polymer intermolecular hydrogen bonding, which reduces the crystal packing. Irradiated (PVP) improved the rate of (Amlo) dissolution compared to unirradiated (PVP).

show abstract

ESR investigations of γ‐irradiated sulfur‐containing vinylpolymers

Mönig

Ringsdorf

1974

Makromol. Chem.

View full text Add to dashboard Cite

The formation and behaviour of radiation‐induced free radicals in statistical copolymers of ethoxyvinylthiomethane (1a) with N‐vinylpyrrolidone (2) (1:2,5) and of ethylthiovinylthiomethane (1b) with 2 (1:3,5) has been studied using electron spin resonance spectroscopy. After a γ‐irradiation of the copolymers at 77K Cα‐radicals in the vinylpyrrolidone moieties could be detected. Investigations on the behaviour of these radicals with an annealing procedure revealed that only in the copolymer (3b) with the dithioacetal group a transfer reaction of hydrogen atoms to the Cα‐radicals in the vinylpyrrolidone moieties occurs. This process may be regarded as a repair mechanism.

show abstract

Radical transfer reactions in γ-irradiated sulphur-containing vinylpolymers

Cited by 5 publications

References 21 publications

ESR Spectroscopy in Polymer Research

ESR Spectroscopy in Polymer Research

Improvement of In Vitro Dissolution of the Poor Water-Soluble Amlodipine Drug by Solid Dispersion with Irradiated Polyvinylpyrrolidone

ESR investigations of γ‐irradiated sulfur‐containing vinylpolymers

Contact Info

Product

Resources

About