The removal of residuals and oligomers from poly(2‐hydroxyethylmethacrylate)

Brynda, Eduard; Štol, M.; Chytrý, Vladimír; Cífková, I.

doi:10.1002/jbm.820190923

Cited by 18 publications

(8 citation statements)

References 5 publications

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“…As reported by the literature,13, 14 unknown compounds, very likely low molecular weight oligomers and hydrolysis products containing carboxylic groups, are still released in water even after several months of purification.…”

Section: Resultsmentioning

confidence: 79%

Bioerodible hydrogels based on 2‐hydroxyethyl methacrylate: Synthesis and characterization

Chiellini

Petrucci

Ranucci

et al. 2002

J of Applied Polymer Sci

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Biocompatible polymers with specific shape and tailored hydrogel properties were obtained by polymerization of mixtures of 2-hydroxyethyl methacrylate (HEMA) with 1-8 wt % ethylene glycol dimethacrylate (EGDMA) or tetra(ethylene glycol) diacrylate (TEGDA) as crosslinking agents, by using a redox initiator. Introduction of charged positive and negative groups was easily achieved by direct polymerization of appropriate monomer mixtures and by chemical transformation of preformed hydrogels. Investigation of the swelling behavior of the prepared hydrogels evidenced an appreciable dependence on both solvent type and polymer chemical structure. Additionally, the solvation process resulted in being controlled by solvent diffusion, according to a Fickian II mechanism. The presence of several types of water with different melting behavior was observed in fully swollen hydrogels.

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Section: Resultsmentioning

confidence: 79%

Bioerodible hydrogels based on 2‐hydroxyethyl methacrylate: Synthesis and characterization

Chiellini

Petrucci

Ranucci

et al. 2002

J of Applied Polymer Sci

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“…As the graft chains become hydrophobic, the network shrinks at the LCST due to hydrophobic aggregation and water is rapidly released from the gel 30, 31. On the other hand, it is well known that PHEMA contains crosslinked oligomers having carboxylic moities 32. These derivatives with a small quantity of methacrylic acid, which cannot easily be removed by purification, can be copolymerized in the networks of PHEMA, PVP and VP/HEMA gels 33.…”

Section: Resultsmentioning

confidence: 99%

Swelling behavior of pH‐ and temperature‐sensitive copolymers containing 2‐hydroxy‐ethyl methacrylate and N‐vinyl‐2‐pyrrolidone crosslinked with new crosslinkers

Atta

Arndt

2004

Polymer International

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Copolymers of 2-hydroxyethyl methacrylate (HEMA) and N-vinyl-2-pyrrolidone (VP) and homopolymers of HEMA and VP were crosslinked in the presence of different mol% of melamine trimethacrylamide (MMAm) and melamine triacrylamide (MAAm) as crosslinkers by bulk radical polymerization. The resultant xerogels were characterized by extracting the soluble fractions and measuring the equilibrium water content. Lower critical solution transition temperatures (LCST) were measured by DSC. The properties of crosslinked HEMA and VP copolymers, VP and HEMA series were evaluated in terms of compositional drift of polymerization, heterogeneous crosslinking, and chemical structure of the relevant components. Soluble fractions of the crosslinked networks were reduced by varying the MAAm and MMAm concentrations. The influence of environmental conditions such as temperature and pH on the swelling behavior of these polymeric gels was investigated. The swelling behaviors of the resulting gels show pH sensitivity. This behavior is explained on the basis that amide groups of VP or crosslinkers could be hydrolyzed to form negatively charged carboxylate ion groups in the produced networks in response to an external pH variation.

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“…The mixture was then allowed to polymerize between two clean glass plates overnight separated by a 0.64-mm-thick Teflon gasket. The pHEMA film was released from the glass plates and soaked in distilled water for 5 h with frequent exchange of water to leach out unreacted monomers, initiators, and oligomer residues, a method consistent with that used by Brynda et al 13 who reported that most impurities were washed out within the first few hours. After leaching, the pHEMA film was punched into smaller specimens for surface modification with dodecyl isocyanate.…”

Section: Phema-based Drug Depot Synthesismentioning

confidence: 92%

Self-assembled molecular structures as ultrasonically-responsive barrier membranes for pulsatile drug delivery

Kwok

Mourad

Crum

et al. 2001

J. Biomed. Mater. Res.

107

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Noninvasive ultrasound has been shown to increase the release rate on demand from drug delivery systems; however, such systems generally suffer from background drug leaching. To address this issue, a drug-containing polymeric monolith coated with a novel ultrasound-responsive coating was developed. A self-assembled molecular structure coating based on relatively impermeable, ordered methylene chains forms an ultrasound-activated on-off switch in controlling drug release on demand, while keeping the drug inside the polymer carrier in the absence of ultrasound. The orderly structure and molecular orientation of these C12 n-alkyl methylene chains on polymeric surfaces resemble self-assembled monolayers on gold. Their preparation and characterization have been published recently (Kwok et al. [Biomacromolecules 2000;1(1):139-148]). Ultrasound release studies showed that a copolymer of 2-hydroxyethyl methacrylate and ethylene glycol dimethacrylate (MW 400) coated with such an ultrasound-responsive membrane maintained sufficient insulin for multiple insulin delivery, compared with a substantial burst release during the first 2 h from uncoated samples. With appropriate surface coating coverage, the background leach rate can be precisely controlled. The biological activity of the insulin releasate was tested by assessing its ability to regulate [C14]-deoxyglucose uptake in 3T3-L1 adipocyte cells in a controlled cell culture environment. Uptake triggered by released insulin was comparable to that of the positive insulin control. The data demonstrate that the released insulin remains active even after the insulin had been exposed to matrix synthesis and the methylene chain coating process.

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The removal of residuals and oligomers from poly(2‐hydroxyethylmethacrylate)

Cited by 18 publications

References 5 publications

Bioerodible hydrogels based on 2‐hydroxyethyl methacrylate: Synthesis and characterization

Bioerodible hydrogels based on 2‐hydroxyethyl methacrylate: Synthesis and characterization

Swelling behavior of pH‐ and temperature‐sensitive copolymers containing 2‐hydroxy‐ethyl methacrylate and N‐vinyl‐2‐pyrrolidone crosslinked with new crosslinkers

Self-assembled molecular structures as ultrasonically-responsive barrier membranes for pulsatile drug delivery

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