Thermoreversible gelation of poly(ethylene oxide) biodegradable polyester block copolymers. II

Choi, Sung Won; Choi, Si Young; Jeong, Byeongmoon; Kim, Sung Wan; Lee, Sang Soo

doi:10.1002/(sici)1099-0518(19990701)37:13<2207::aid-pola35>3.0.co;2-0

Cited by 79 publications

(27 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The gel-to-sol properties of the PEG/polyester diblock and triblock copolymers in water depended on the hydrophobic/hydrophilic balance, block length, hydrophobicity, and stereoregularity of the hydrophobic block. [10,11] PEG-(D,L-lactide)-PEG (PEG-PLA-PEG) triblock copolymers (MW of MPEG ¼ 2 000-5 000) were recently produced by coupling MPEG-PLA diblock copolymers using adipoyl chloride. [12] Rheological measurements showed a gel-tosol transition in concentrated polymer solutions, with an increase in temperature.…”

Section: Poly(ethylene Glycol) (Peg)/polyestermentioning

confidence: 99%

Injectable Biodegradable Hydrogels

Nguyen

Lee

2010

Macromolecular Bioscience

Self Cite

422

343

View full text Add to dashboard Cite

Injectable biodegradable copolymer hydrogels, which exhibit a sol–gel phase transition in response to external stimuli, such as temperature changes or both pH and temperature (pH/temperature) alterations, have found a number of uses in biomedical and pharmaceutical applications, such as drug delivery, cell growth, and tissue engineering. These hydrogels can be used in simple pharmaceutical formulations that can be prepared by mixing the hydrogel with drugs, proteins, or cells. Such formulations are administered in a straightforward manner, through site‐specific control of release behavior, and the hydrogels are compatible with biological systems. This review will provide a summary of recent progress in biodegradable temperature‐sensitive polymers including polyesters, polyphosphazenes, polypeptides, and chitosan, and pH/temperature‐sensitive polymers such as sulfamethazine‐, poly(β‐amino ester)‐, poly(amino urethane)‐, and poly(amidoamine)‐based polymers. The advantages of pH/temperature‐sensitive polymers over simple temperature‐sensitive polymers are also discussed. A perspective on the future of injectable biodegradable hydrogels is offered.magnified image

show abstract

Section: Poly(ethylene Glycol) (Peg)/polyestermentioning

confidence: 99%

Injectable Biodegradable Hydrogels

Nguyen

Lee

2010

Macromolecular Bioscience

Self Cite

422

343

View full text Add to dashboard Cite

show abstract

“…[1][2][3][4][5][6][7] Many kinds of temperature-sensitive biodegradable block copolymers consisting of poly(ethylene glycol) (PEG) and biodegradable polyester such as poly(L-lactic acid) (PLLA), poly(DL-lactic acid) (PDLLA), poly(DL-lactic acidco-glycolic acid) (PLGA), and poly("-caprolactone) (PCL) were studied for this purpose. 5,[8][9][10][11][12][13][14][15][16] Kim et al studied the gelation behavior of PEG-PLGA-PEG with PEG having fixed molecular weight of 550 and PLGA having various molecular weights and various ratios of DL-lactide to glycolide, which showed gel to sol transition (upper boundary curve) and sol to gel transition (lower boundary curve) as the temperature was increased. 5 Lee et al reported that PLGA-PEG-PLGA triblock copolymer with a central PEG block demonstrated an interesting reversible sol-gel transition in water.…”

mentioning

confidence: 99%

Temperature-Sensitive Sol-Gel Transition Behavior of Biodegradable Four-Arm Star-Shaped PEG-PLGA Block Copolymer Aqueous Solution

2009

View full text Add to dashboard Cite

Biodegradable four-arm star-shaped poly(ethylene glycol-b-DL-lactic acid-co-glycolic acid) block copolymers (4arm PEG-PLGA) were synthesized by ring-opening polymerization of DL-lactide and glycolide using 4arm PEG as an initiator and Sn(oct) 2 as a catalyst. In aqueous solution, they showed reversible sol to gel to sol transition behavior while increasing the temperature from 0 C to 40 C. The larger the molecular weight or the stronger the relative hydrophobicity of the hydrophobic PLGA block, the smaller the critical gel concentration (CGC). 4arm PEG-PLGA formed gels at lower CGC (13 wt %) than the inverse 4arm PLGA-PEG (24 wt %) due to the differences in their molecular structures.KEY WORDS: Hydrogels / Star Polymers / Sol-gel Transition / Biodegradable / Temperature-sensitive polymers of which aqueous solutions undergo sol-gel transition in response to temperature changes are especially attractive in drug delivery applications as an in situ gel-forming device. These polymers might be mixed with therapeutic agents such as drugs, cells or proteins in the sol state and injected using a syringe into the body to form a depot system.

show abstract

“…The sample tubes were placed in a water-bath, where these tubes was then heated slowly from 0 to 60 °C at 0.2°C/min with a 5min hold at each temperature. The sol-gel transition at each temperature was determined by angling the vial horizontally after keeping it at a constant temperature for 5min, as described in our previous paper [19,20].…”

Section: Sol-gel Phase Transition Measurementmentioning

confidence: 99%

“…It produced a critical gel pH (CGpH) and two critical gel temperature (CGT) in the curve (a lower CGT is the transition from sol to gel, and an upper CGT is the transition from gel to sol) (Figure 3). At At low temperature (10 °C) and high pH (8.5), OS was ionized and the solubility of the pentablock chain was increased [19]. Furthermore, the hydrophilic/hydrophobic balance of OS/PCL shifted to a more hydrophilic character at low temperature, as a result, OS-PCL-PEG-PCL-OS solution stayed as a sol state.…”

Section: Sol-gel Phase Transition Diagrammentioning

confidence: 99%

pH/TEMPERATURE SENSITIVE PENTABLOCK BASED ON D,L-SERINE

Huynh

2018

JST

View full text Add to dashboard Cite

For recent decades, researchers have been increasing their attention to pH/temperaturesensitive polymers as drug/protein delivery systems. In this research, we aim to synthesize a new pH/temperature sensitive pentablock based on D,L-Serine. Amino groups of D,L-Serine were modified with benzenesulfonyl chloride in order to create sulfonamide groups as desired pHsensitive groups. Pentablocks were then synthesized by conjugation reaction between carboxylic, hydroxyl groups of D,L-Serine and hydroxyl-terminal groups of temperature sensitive triblock PCL-PEG-PCL. The synthesized products were analyzed by 1H-NMR and their molecular weights were measured by gel permeation chromatography (GPC). The sol-gel transition of pentablock was also investigated by the inverting test method. The pH dependent property of the pH sensitive moiety could be very useful for preparing drug carriers.

show abstract

Thermoreversible gelation of poly(ethylene oxide) biodegradable polyester block copolymers. II

Cited by 79 publications

References 31 publications

Injectable Biodegradable Hydrogels

Injectable Biodegradable Hydrogels

Temperature-Sensitive Sol-Gel Transition Behavior of Biodegradable Four-Arm Star-Shaped PEG-PLGA Block Copolymer Aqueous Solution

pH/TEMPERATURE SENSITIVE PENTABLOCK BASED ON D,L-SERINE

Contact Info

Product

Resources

About