Mechanism of Shape Evolution in Ag Nanoprisms Stabilized by Thiol-Terminated Poly(ethylene glycol): An in Situ Kinetic Study

2013 ◽  
Vol 25 (21) ◽  
pp. 4206-4214 ◽  
Author(s):  
Lijia Liu ◽  
Cheryl A. Burnyeat ◽  
Reegan S. Lepsenyi ◽  
Izuoma O. Nwabuko ◽  
Timothy L. Kelly
Keyword(s):  
Ethylene Glycol ◽  
Kinetic Study ◽  
Shape Evolution ◽  
Poly Ethylene Glycol ◽  
Poly Ethylene

scholarly journals Poly(ethylene glycol)-b-poly(1,3-trimethylene carbonate) Copolymers for the Formulation of In Situ Forming Depot Long-Acting Injectables

Pharmaceutics ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 605
Author(s):  
Marie-Emérentienne Cagnon ◽  
Silvio Curia ◽  
Juliette Serindoux ◽  
Jean-Manuel Cros ◽  
Feifei Ng ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Surface Erosion ◽  
Sustained Delivery ◽  
Trimethylene Carbonate ◽  
Poly Ethylene Glycol ◽  
In Situ Forming ◽  
Poly Ethylene ◽  
Long Acting

This article describes the utilization of (methoxy)poly(ethylene glycol)-b-poly(1,3-trimethylene carbonate) ((m)PEG–PTMC) diblock and triblock copolymers for the formulation of in situ forming depot long-acting injectables by solvent exchange. The results shown in this manuscript demonstrate that it is possible to achieve long-term drug deliveries from suspension formulations prepared with these copolymers, with release durations up to several months in vitro. The utilization of copolymers with different PEG and PTMC molecular weights affords to modulate the release profile and duration. A pharmacokinetic study in rats with meloxicam confirmed the feasibility of achieving at least 28 days of sustained delivery by using this technology while showing good local tolerability in the subcutaneous environment. The characterization of the depots at the end of the in vivo study suggests that the rapid phase exchange upon administration and the surface erosion of the resulting depots are driving the delivery kinetics from suspension formulations. Due to the widely accepted utilization of meloxicam as an analgesic drug for animal care, the results shown in this article are of special interest for the development of veterinary products aiming at a very long-term sustained delivery of this therapeutic molecule.

A bioactive hyaluronic acid–based hydrogel cross-linked by Diels–Alder reaction for promoting neurite outgrowth of PC12 cells

2017 ◽  
Vol 32 (4) ◽  
pp. 382-396 ◽  
Author(s):  
Dongming Xing ◽  
Lie Ma ◽  
Changyou Gao
Keyword(s):  
Hyaluronic Acid ◽  
Ethylene Glycol ◽  
Neurite Outgrowth ◽  
Pc12 Cells ◽  
Alder Reaction ◽  
Poly Ethylene Glycol ◽  
Substitution Degree ◽  
Poly Ethylene

In order to improve neurite outgrowth on the in situ formed hyaluronic acid–based hydrogel, furan and methacrylate groups were grafted on hyaluronic acid successively. Furthermore, a laminin-derived peptide CQAASIKVAV was covalently immobilized via the Michael addition. The furan- and peptide-modified hyaluronic acid was then cross-linked in situ by mixing with bismaleimide poly(ethylene glycol) at 37 °C to obtain a bioactive hyaluronic acid–based hydrogel. The hyaluronic acid derivatives were characterized by 1H NMR and Fourier transform infrared spectroscopy. The gelation, swelling, and mechanical property of the hydrogels were analyzed. The modulus of the hydrogel could be tuned by changing furan substitution degree, while the peptide concentration could be changed by the ratio of furan- and peptide-modified hyaluronic acid with hyaluronic acid–furan. In vitro culture of PC12 cells showed that the longest neurite outgrowth appeared on the hyaluronic acid–poly(ethylene glycol) hydrogel with the highest peptide content (the substitution degree of peptide in furan- and peptide-modified hyaluronic acid was 23 %) and a lower threshold modulus of 4.5 kPa. The furan and methacrylate-functionalized hyaluronic acid provides a versatile platform for diverse functionalization and can be used for modulation of other cell behaviors as well.

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