Syntheses, Characterization, and in Vitro Degradation of Ethyl Cellulose-graft-poly(ε-caprolactone)-block-poly(l-lactide) Copolymers by Sequential Ring-Opening Polymerization

2007 ◽  
Vol 8 (4) ◽  
pp. 1101-1108 ◽  
Author(s):  
Weizhong Yuan ◽  
Jinying Yuan ◽  
Fengbo Zhang ◽  
Xuming Xie
Keyword(s):  
Ring Opening ◽  
Ethyl Cellulose ◽  
Ring Opening Polymerization ◽  
In Vitro Degradation ◽  
Lactide Copolymers

scholarly journals Oligo(serine ester) Charge-Altering Releasable Transporters: Organocatalytic Ring-Opening Polymerization and their Use for in Vitro and in Vivo mRNA Delivery

2019 ◽  
Vol 141 (21) ◽  
pp. 8416-8421 ◽  
Author(s):  
Nancy L. Benner ◽  
Rebecca L. McClellan ◽  
Christopher R. Turlington ◽  
Ole A. W. Haabeth ◽  
Robert M. Waymouth ◽  
...  
Keyword(s):  
Ring Opening ◽  
Ring Opening Polymerization

Preparation and Degradation Properties of Hydroxyethyl Chitosan-g-Poly(D,L-Lactide) Copolymers

2012 ◽  
Vol 457-458 ◽  
pp. 308-313
Author(s):  
Bing Hong Luo ◽  
Jian Hua Li ◽  
Wan Xu ◽  
Chang Ren Zhou
Keyword(s):  
Ring Opening ◽  
Ph Value ◽  
Saline Water ◽  
Feed Ratio ◽  
Casting Method ◽  
Composition And Structure ◽  
Solution Casting Method ◽  
Lactide Copolymers ◽  
Degradation Properties

The goal of the present study was to investigate the degradation of hydroxyethyl chitosan-g-poly(D,L-lactide) (HECS-g-PDLLA) copolymers in vitro. For this purpose, HECS-g-PDLLA copolymers were firstly synthesized by bulk ring-opening polymerization with different nD,L-lactide:naminoglucoside feed ratio. Then, a series of poly(D,L-lactide), chitosan and HECS-g-PDLLA copolymers films were prepared by solution casting method, and their degradation were carried out in vitro in saline water at 37 °C. The degradation properties were investigated by measurement of pH value, weight loss, and changes in the composition and structure of the HECS-g-PDLLA copolymers films with time. Results showed that the degradation of the HECS-g-PDLLA copolymers occurred firstly on the poly(D,L-lactide) side chains. The degradation rate of the graft copolymers obviously faster than that of CS, and can be controlled by changing the value of nD,L-lactide:naminoglucoside. Due to the alkalinity of CS, the pH value of saline water for HECS-g-PDLLA copolymers degradation higher than that of PDLLA.

Ring Opening Polymerization of ε-Caprolactone Catalyzed with Magnesium Lactate

2009 ◽  
Vol 610-613 ◽  
pp. 1208-1210 ◽  
Author(s):  
Lian Liu ◽  
Zhi Yong Wei ◽  
Pei Wang ◽  
Min Qi
Keyword(s):  
Nmr Spectroscopy ◽  
Reaction Temperature ◽  
13C Nmr ◽  
Ring Opening ◽  
Synthesis Method ◽  
13C Nmr Spectroscopy ◽  
Ring Opening Polymerization ◽  
Moderate Activity ◽  
Lactide Copolymers

The aim of this paper is to present a synthesis method of poly(ε-caprolactone) by the ring opening polymerization of ε-caprolactone catalyzed with nontoxic magnesium lactate. The results indicated that Mg(Lac)2 is a catalyst with moderate activity for the polymerization of ε-caprolactone. Effects of the catalyst and reaction temperatures on the microstructure of the ε-caprolactone and L-lactide copolymers were investigated by means of 13C-NMR spectroscopy. An increase in the reaction temperature enhances the role of transesterification and the extent of randomness.

scholarly journals Synthesis, Properties, and In Vitro Hydrolytic Degradation of Poly(d,l-lactide-co-glycolide-co-ε-caprolactone)

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Yixiu Liu ◽  
Xizhuang Bai ◽  
A. Liang
Keyword(s):  
Ring Opening ◽  
Degradation Products ◽  
Hydrolytic Degradation ◽  
Ring Opening Polymerization ◽  
Random Copolymers ◽  
Thermal And Mechanical Properties ◽  
Degradation Rates ◽  
Synthesis Properties ◽  
Acidic Degradation

Random copolymers of poly(d,l-lactide-co-glycolide-co-ε-caprolactone) (PLGC) were synthesized by the ring-opening polymerization of d,l-lactide (DLLA), glycolide (GA), andε-caprolactone (CL). The effects of CL on the copolymers were evaluated to prepare suitable copolymers with controlled properties. Our results showed that the CL content significantly influenced the thermal and mechanical properties of the copolymers and that the CL content in compositions could be altered to control properties of random copolymers. The in vitro hydrolytic degradation of the resulting implants showed that the degradation rate of PLGC was lower than that of PLGA, which could markedly reduce acidic degradation products. Finally, we demonstrated that higher CL contents in compositions slowed degradation rates.

scholarly journals Tailor-made block copolymers of l-, d- and rac-lactides and ε-caprolactone via one-pot sequential ring opening polymerization by pyridylamidozinc(ii) catalysts

RSC Advances ◽  
2019 ◽  
Vol 9 (56) ◽  
pp. 32771-32779 ◽  
Author(s):  
Ilaria D'Auria ◽  
Massimo Christian D'Alterio ◽  
Consiglia Tedesco ◽  
Claudio Pellecchia
Keyword(s):  
Block Copolymers ◽  
Ring Opening ◽  
Room Temperature ◽  
Reaction Times ◽  
Ring Opening Polymerization ◽  
One Pot ◽  
Variable Block ◽  
Lactide Copolymers

New 3-coordinated Zn ROP catalysts afford lactide stereo-block copolymers with variable block lengths and steric structures and diblock ε-caprolactone-lactide copolymers at room temperature and in short reaction times.

Preparation and Characterization of Poly (vinylbenzyl chloride)-b-poly (lactide) Copolymers via Nitroxide-Mediated Controlled Radical and Ring-Opening Polymerization

2012 ◽  
Vol 554-556 ◽  
pp. 295-298 ◽  
Author(s):  
Shao Hua Shen ◽  
Ying Xiang Duan ◽  
Qing Quan Liu ◽  
Qiu Guao Xiao
Keyword(s):  
Molecular Weight ◽  
Radical Polymerization ◽  
1H Nmr ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Controlled Radical Polymerization ◽  
Polydispersity Index ◽  
Molecular Weights ◽  
Lactide Copolymers

Hydroxyl-terminated poly(vinylbenzyl chloride) (PVBCOH) were synthesized using nitroxide-mediated controlled radical polymerization. Then, PVBCOH was used as a macro-initiator for ring-opening polymerization of lactide (LA) in the presence of stannous octanoate (Sn(Oct)2) as a catalyst. The structures, molecular weights and polydispersity index (PDI) of PVBCOH and PVBC-b-PLA were characterized by 1H-NMR, and GPC, respectively. The results indicated that PDI of PVBCOH and PVBC-b-PLA was 1.63 and 1.27, respectively. Moreover, the molecular weight and PDI of PVBCOH and PVBC-b-PLA could be well tuned by changing monomer-to-initiator ratio.

A Recommender System for Inverse Design of Polycarbonates and Polyesters

2020 ◽  
Author(s):  
Nathaniel Park ◽  
Dmitry Yu. Zubarev ◽  
James L. Hedrick ◽  
Vivien Kiyek ◽  
Christiaan Corbet ◽  
...  
Keyword(s):  
Ring Opening ◽  
High Performance ◽  
Recommendation System ◽  
Polymeric Materials ◽  
Monomer Conversion ◽  
Design Strategy ◽  
Ring Opening Polymerization ◽  
Inverse Design ◽  
False Negatives ◽  
Accelerate Development

The convergence of artificial intelligence and machine learning with material science holds significant promise to rapidly accelerate development timelines of new high-performance polymeric materials. Within this context, we report an inverse design strategy for polycarbonate and polyester discovery based on a recommendation system that proposes polymerization experiments that are likely to produce materials with targeted properties. Following recommendations of the system driven by the historical ring-opening polymerization results, we carried out experiments targeting specific ranges of monomer conversion and dispersity of the polymers obtained from cyclic lactones and carbonates. The results of the experiments were in close agreement with the recommendation targets with few false negatives or positives obtained for each class.<br>

Formulation and Evaluation of Bilayer Sustained Release Tablets of Salbutamol and Theophylline

2009 ◽  
Vol 2 (3) ◽  
pp. 638-646
Author(s):  
R. Nagaraju ◽  
Rajesh Kaza
Keyword(s):  
Ethyl Cellulose ◽  
Xanthan Gum ◽  
Dosage Forms ◽  
In Vitro Dissolution ◽  
Dissolution Studies ◽  
Sustained Release Tablets ◽  
Dissolution Apparatus ◽  
Single Dosage

Salbutamol and theophylline are available in conventional dosage forms, administered four times a day, leading to saw tooth kinetics and resulting in ineffective therapy. The combination of these two drugs in a single dosage form will enhance the patient compliance and prolong bronchodilation. Various polymers, such as hydroxy propyl methylcellulose K4M (HPMC- K4M), hydroxy propyl methylcellulose K100M (HPMC- K100M), xanthan gum, ethyl cellulose and hydroxy propyl methylcellulose phthalate (HPMC-P) were studied. HPMC-P and HPMC- K4M were found to be best in controlling the release. In-vitro dissolution studies were carried out for all the bi-layered tablets developed using USP dissolution apparatus type 2 (paddle). It was found that the tablet FB15-FW3 showed 50% release of salbutamol in first hour and the remaining was released for eight hours. However, theophylline was found to be released as per the USP specifications. The IR spectrum was taken for FB15-FW3 formulation and it revealed that there is no disturbance in the principal peaks of pure drugs salbutamol and theophylline. This further confirms the integrity of pure drugs and no incompatibility of them with excipients. Also, formulation of FB15-FW3 has shown required release pattern and complies with all the evaluated parameters and comparable to the marketed formulation.

In Vitro Degradation Of beta-Amyloid[25-35] Peptide

2001 ◽  
Vol 8 (6) ◽  
pp. 423-428 ◽  
Author(s):  
Krisztina Jost ◽  
Jozsef Varga ◽  
Botond Pence ◽  
Marta Zarandi
Keyword(s):  
Beta Amyloid ◽  
In Vitro Degradation
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