Thermosensitive polymers: Synthesis, characterization, and delivery of proteins

Singh, Somnath; Webster, Dean C.; Singh, Jagdish

doi:10.1016/j.ijpharm.2007.03.054

Cited by 50 publications

(25 citation statements)

References 33 publications

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“…The hydrogel matrix protects protein therapeutics from enzymatic degradation and provides sustained release over a longer period of time, eliminating the need for frequent re peated injections. Various biodegradable copolymers composed of hydrophobic polymer blocks including polycaprolactone (PCL), polylactic acid (PLA), polyglycolide (PGA) and poly lactide-co-glycolide (PLGA), and hydrophilic polymer blocks in particular polyethylene glycol (PEG) have been investigated for their thermosensitive behavior [11–13]. Adjustment of the hydrophilic-hydrophobic balance in the block copolymer backbone allows manipulation of the sol-gel transition curve.…”

Section: Introductionmentioning

confidence: 99%

Novel Thermosensitive Pentablock Copolymers for Sustained Delivery of Proteins in the Treatment of Posterior Segment Diseases

Patel¹,

Vaishya²,

Yang³

et al. 2014

PPL

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Biodegradable and injectable in situ thermosensitive hydrogels were investigated for sustained delivery of protein therapeutics in the treatment of ocular posterior segment neovascular diseases. A series of triblock (TB, polycaprolac-tone-polyethylene glycol-polycaprolactone (PCL-PEG-PCL), B-A-B) and pentablock copolymers (PBCs) (polylactic acid (PLA)-PCL-PEG-PCL-PLA (C-B-A-B-C) and PEG-PCL-PLA-PCL-PEG (A-B-C-B-A)) were synthesized and evaluated for their thermosensitive behavior. Effects of molecular weight, hydrophobicity and block arrangement on polymer crystallinity, sol-gel transition, micelle size, viscosity and in vitro drug release were examined. Results from sol-gel transition studies demonstrated that aqueous solutions of block copolymers can immediately transform to hydrogel upon exposure to physiological temperature. PBC provide significantly longer sustained release (more than 20 days) of IgG relative to TB copolymers. Moreover, kinematic viscosity of aqueous solution at 25°C for A-B-C-B-A type of PBCs was noticeably lower than the TB (B-A-B) copolymers and other PBCs with C-B-A-B-C block arrangements suggesting desired syringeability. The presence of PLA blocks in PBCs (C-B-A-B-C and A-B-C-B-A) significantly reduces crystallinity. Hence, it is anticipated that PBCs will have a faster rate of degradation relative to PCL-PEG-PCL based TB copolymers. PBCs also exhibited excellent cell viability and biocompatibility on ARPE-19 (human retinal pigment epithelial cell line) and RAW-264.7 (mouse macrophage cells), likely rendering it safe for ocular applications. Owing to biodegradability, thermosensitivity, ease of handling and biocompatibility PBC hydrogels can be considered as promising biomaterial for sustained delivery of protein therapeutics to the back of the eye.

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Section: Introductionmentioning

confidence: 99%

Novel Thermosensitive Pentablock Copolymers for Sustained Delivery of Proteins in the Treatment of Posterior Segment Diseases

Patel¹,

Vaishya²,

Yang³

et al. 2014

PPL

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“…The PLA-PEG-PLA copolymers were synthesized using a method previously described by Singh et al 15 PEG block length of 1500 and D, L-lactide were used for synthesis. Under nitrogen, PEG was dried at 100 • C in a three-necked flask for 30 min, followed by addition of D,L-lactide.…”

Section: Synthesis and Characterization Of Triblock Copolymersmentioning

confidence: 99%

“…Delivery systems containing PLGA-PEG-PLGA thermosensitive triblock copolymer showed a controlled release of various proteins including insulin for 2 weeks. 15,16 In case of formulations containing insulin, the release profile exhibited a high burst release, most probably due to the high content of the hydrophilic glycolic acid blocks. 16 Thus, there is a need to develop triblock copolymers that can control the release of insulin for longer duration.…”

Section: Introductionmentioning

confidence: 99%

Basal level insulin delivery: In vitro release, stability, biocompatibility, and in vivo absorption from thermosensitive triblock copolymers

Al-Tahami

Oak

Mandke

et al. 2011

Journal of Pharmaceutical Sciences

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“…It has been demonstrated that smart polymers can be used to develop delivery systems in order to overcome dosing frequency and increase patient compliance [7][8][9][10]. One of such polymers is thermosensitive polymer which is soluble in water at room temperature but turns into gel at body temperature and releases the incorporated biologics at a controlled rate for longer duration in biologically and conformationally stable form after a single subcutaneous injection [11].…”

Section: Introductionmentioning

confidence: 99%

Effect of Molar Mass and Water Solubility of Incorporated Molecules on the Degradation Profile of the Triblock Copolymer Delivery System

et al. 2015

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The purpose of this study was to investigate the effects of size and type of incorporated model molecules on the polymer degradation and release profile from thermosensitive triblock copolymer based controlled delivery systems. In vitro release of the incorporated molecules demonstrated slow release for risperidone (molecular weight (M w ) = 410.48 Da; partition coefficient (K o/w ) = 3.49), while bovine serum albumin (BSA) (M w = "66,400 Da; K o/w = 0.007) and insulin (M w = 5808 Da; K o/w = 0.02) showed initial burst release followed by controlled release. The proton NMR, Gel Permeation Chromatography, and Cryo-SEM studies suggest that the size and partition coefficient of incorporated molecules influence the pore size, polymer degradation, and their release. In spite of using a similar polymer delivery system the polymer degradation rate and drug release notably differ for these model molecules. Therefore, size and oil-water partition coefficient are important factors for designing the controlled release formulation of therapeutics from triblock copolymer based delivery systems.Polymers 2015, 7 1511

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Thermosensitive polymers: Synthesis, characterization, and delivery of proteins

Cited by 50 publications

References 33 publications

Novel Thermosensitive Pentablock Copolymers for Sustained Delivery of Proteins in the Treatment of Posterior Segment Diseases

Novel Thermosensitive Pentablock Copolymers for Sustained Delivery of Proteins in the Treatment of Posterior Segment Diseases

Basal level insulin delivery: In vitro release, stability, biocompatibility, and in vivo absorption from thermosensitive triblock copolymers

Effect of Molar Mass and Water Solubility of Incorporated Molecules on the Degradation Profile of the Triblock Copolymer Delivery System

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