A New Class of Biodegradable Thermosensitive Polymers. I. Synthesis and Characterization of Poly(organophosphazenes) with Methoxy-Poly(ethylene glycol) and Amino Acid Esters as Side Groups

Song, Soo‐Chang; Lee, Sang Beom; Jin, Jung‐Il; Sohn, Youn Soo

doi:10.1021/ma981190p

Cited by 124 publications

(107 citation statements)

References 18 publications

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“…Many homo-and copolymers of NiPAAm are not biodegradable [48], a fact that may prove problematic for some biomedical engineering applications. Nakayama and colleagues [37] have prepared thermally responsive, biodegradable polymeric micelles for controlled drug release.…”

Section: N-isopropylacrylamide-based Systemsmentioning

confidence: 99%

“…Poly(organophosphazenes) grafted with mPEG and amino acid esters were reported as a new class of biodegradable and thermosensitive polymers in 1999 [48]. Sohn and colleagues [80] developed a correlation for the LCST of these polymers as a function of their molecular structure, which comprises hydrophilic (PEG) and hydrophobic (amino acid esters) side groups.…”

Section: Poly(organophosphazenes)mentioning

confidence: 99%

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Thermoresponsive hydrogels in biomedical applications

Klouda

Mikos

2008

European Journal of Pharmaceutics and Biopharmaceutics

1,113

696

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Environmentally responsive hydrogels have the ability to turn from solution to gel when a specific stimulus is applied. Thermoresponsive hydrogels utilize temperature change as the trigger that determines their gelling behavior without any additional external factor. These hydrogels have been interesting for biomedical uses as they can swell in situ under physiological conditions and provide the advantage of convenient administration. The scope of this paper is to review the aqueous polymer solutions that exhibit transition to gel upon temperature change. Typically, aqueous solutions of hydrogels used in biomedical applications are liquid at ambient temperature and gel at physiological temperature. The review focuses mainly on hydrogels based on natural polymers, N-isopropylacrylamide polymers, poly(ethylene oxide)-b-poly(propylene oxide)-bpoly(ethylene oxide) polymers as well as poly(ethylene glycol)-biodegradable polyester copolymers.

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Section: N-isopropylacrylamide-based Systemsmentioning

confidence: 99%

Section: Poly(organophosphazenes)mentioning

confidence: 99%

Thermoresponsive hydrogels in biomedical applications

Klouda

Mikos

2008

European Journal of Pharmaceutics and Biopharmaceutics

1,113

696

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“…Among the poly(organophosphazenes) with methoxy-poly(ethylene glycol) and amino acid esters as side groups previously synthesized, 14 Measurements of LCST. The LCST temperature of the aqueous solution of the polymer (5%) containing different kinds and concentrations of saccharides (0-1.0 M) was detected visually in a closed glass tube and the temperature was controlled by immersion of the glass tube in an oil bath.…”

Section: Methodsmentioning

confidence: 99%

“…12,13 In our previous work, it was reported that the poly(organophosphazenes) bearing methoxy-poly(ethylene glycol) (MPEG) and amino acid esters as side groups are not only biodegradable but also thermosensitive, showing a wide range of LCST depending on compositions and kinds of the side groups. 14 We have also studied the salt effect on these polymers in aqueous solutions. 15 In this study, saccharide effects on the LCST of poly-(organophosphazenes) were investigated in detail employing several structurally different saccharides.…”

Section: Introductionmentioning

confidence: 99%

Saccharide Effect on the Lower Critical Solution Temperature of Poly(organophosphazenes) with Methoxy-poly(ethylene glycol) and Amino Acid Esters as Side Groups

2003

Bulletin of the Korean Chemical Society

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The lower critical solution temperature (LCST) of thermosensitive poly(organophosphazenes) with methoxypoly(ethylene glycol) (MPEG) and amino acid esters as side groups was studied as a function of saccharide concentration in aqueous solutions of mono-, di-, and polysaccharides. Most of the saccharides decreased the LCST of the polymers, and the LCST decrease was more prominently observed by saccharides containing a galactose ring, such as D-galactose, D-galactosamine and D-lactose, and also the polysacccharide, 1-6-linked D-dextran effectively decreased the LCST of the polymers. Such an effect was discussed in terms of intramolecular hydrogen bonding of saccharides in polymer aqueous solution. The saccharide effect was found to be almost independent on the kinds of the amino acid esters and MPEG length of the polymers. Such a result implies that the polymer-saccharide interaction in aqueous solution is clearly influenced by the structure of sacchardes rather than by that of the polymers. The acid saccharides such as D-glucuronic and D-lactobionic acid increased the LCST, which seems to be due to their pH effect.

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“…In general, the temperature sensitivity of swelling can be attributed to the delicate hydrophilic-lipophilic balance (HLB) of polymer chains and is affected by the size, configuration, and mobility of alkyl side groups. A sharp swelling transition occurs at LCST, when an optimum HLB value is attained in networks demonstrating sharp thermoresponsive properties; such as poly(NIPAM) networks [161,162].…”

Section: Temperature-sensitive or Thermo-responsive Gelsmentioning

confidence: 99%

Smart polymeric gels: Redefining the limits of biomedical devices

Chaterji

Kwon

Park

2007

Progress in Polymer Science

552

364

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This review describes recent progresses in the development and applications of smart polymeric gels, especially in the context of biomedical devices. The review has been organized into three separate sections: defining the basis of smart properties in polymeric gels; describing representative stimuli to which these gels respond; and illustrating a sample application area, namely, microfluidics. One of the major limitations in the use of hydrogels in stimuli-responsive applications is the diffusion rate limited transduction of signals. This can be obviated by engineering interconnected pores in the polymer structure to form capillary networks in the matrix and by downscaling the size of hydrogels to significantly decrease diffusion paths. Reducing the lag time in the induction of smart responses can be highly useful in biomedical devices, such as sensors and actuators. This review also describes molecular imprinting techniques to fabricate hydrogels for specific molecular recognition of target analytes. Additionally, it describes the significant advances in bottom-up nanofabrication strategies, involving supramolecular chemistry. Learning to assemble supramolecular structures from nature has led to the rapid prototyping of functional supramolecular devices. In essence, the barriers in the current performance potential of biomedical devices can be lowered or removed by the rapid convergence of interdisciplinary technologies.

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A New Class of Biodegradable Thermosensitive Polymers. I. Synthesis and Characterization of Poly(organophosphazenes) with Methoxy-Poly(ethylene glycol) and Amino Acid Esters as Side Groups

Cited by 124 publications

References 18 publications

Thermoresponsive hydrogels in biomedical applications

Thermoresponsive hydrogels in biomedical applications

Saccharide Effect on the Lower Critical Solution Temperature of Poly(organophosphazenes) with Methoxy-poly(ethylene glycol) and Amino Acid Esters as Side Groups

Smart polymeric gels: Redefining the limits of biomedical devices

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