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Preparation of exenatide-loaded linear poly(ethylene glycol)-brush poly(l-lysine) block copolymer: potential implications on diabetic nephropathy.

ABSTRACT: The poly(ethylene glycol)-b-brush poly(l-lysine) polymer (PEG-b-(PELG50-g-PLL3)) was synthesized and evaluated as a nanocarrier for prolonging delivery of exenatide through the abdominal subcutaneous injection route. The isoelectric point of exenatide was 4.86, and exenatide could combine with PEG-b-(PELG50-g-PLL3) polymers via electrostatic interactions at pH 7.4. This polymer was a good candidate for achieving prolonged drug delivery for exenatide, considering its high molecular weight. Besides the physicochemical characterization of the polymer, in vitro and in vivo applications were researched as a sustained exenatide delivery system. In the in vitro release research, 20.16%-76.88% of total exenatide was released from the PEG-b-(PELG50-g-PLL3) polymer within 7 days. The synthesized block-brush polymers and exenatide-block-brush polymers were analyzed by nuclear magnetic resonance spectroscopy, gel permeation chromatography, transmission electron microscopy, nanoparticle size instrument, and scanning electron microscopy. The best formulation was selected for in vivo experimentation to achieve blood glucose control in diabetic rat models using free exenatide as the control. The hypoglycemic action of the formulation following subcutaneous injection in diabetic rats lasted 7 days, and the results indicated that exenatide-block-brush polymers demonstrate enhanced long-acting hypoglycemic action. Besides the hypoglycemic action, exenatide-block-brush polymers significantly alleviated diabetic nephropathy via improving renal function, decreasing oxidative stress injury, decreasing urinary albumin excretion rate, mitigating albumin/creatinine ratio, reducing blood lipids, abating kidney index, weakening apoptosis, and downregulating expression of connective tissue growth factor. All of the results suggested that PEG-b-(PELG50-g-PLL3) polymers could be used as potential exenatide nanocarriers, with efficient encapsulation and sustained release.

SUBMITTER: Tong F

PROVIDER: S-EPMC5500490 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

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Preparation of exenatide-loaded linear poly(ethylene glycol)-brush poly(l-lysine) block copolymer: potential implications on diabetic nephropathy.

Tong Fei F

International journal of nanomedicine 20170629

The poly(ethylene glycol)-b-brush poly(l-lysine) polymer (PEG-b-(PELG50-g-PLL3)) was synthesized and evaluated as a nanocarrier for prolonging delivery of exenatide through the abdominal subcutaneous injection route. The isoelectric point of exenatide was 4.86, and exenatide could combine with PEG-b-(PELG50-g-PLL3) polymers via electrostatic interactions at pH 7.4. This polymer was a good candidate for achieving prolo ...[more]

PMID: 28721043

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Project description:Proton exchange membranes (PEMs) suffer performance degradation under certain conditions-temperatures greater than 80 °C, relative humidity less than 50%, and water retention less than 22%. Novel materials are needed that have improved water retention, stability at higher temperatures, flexibility, conductivity, and the ability to function at low humidity. This work focuses on polyimide-poly(ethylene glycol) (PI-PEG) segmented block copolymer (SBC) membranes with high conductivity and mechanical strength. Membranes were prepared with one of two ionic liquids (ILs), either ethylammonium nitrate (EAN) or propylammonium nitrate (PAN), incorporated within the membrane structure to enhance the proton exchange capability. Ionic liquid uptake capacities were compared for two different temperatures, 25 and 60 °C. Then, conductivities were measured for a series of combinations of undoped or doped unannealed and undoped or doped annealed membranes. Stress and strain tests were performed for unannealed and thermally annealed undoped membranes. Later, these experiments were repeated for doped unannealed and thermally annealed. Mechanical and conductivity data were interpreted in the context of prior small angle X-ray scattering (SAXS) studies on similar materials. We have shown that varying the compositions of polyimide-poly(ethylene glycol) (PI-PEG) SBCs allowed the morphology in the system to be tuned. Since polyimides (PI) are made from the condensation of dianhydrides and diamines, this was accomplished using components having different functional groups. Dianhydrides having either fluorinated or oxygenated functional groups and diamines having either fluorinated or oxygenated diamines were used as well as mixtures of these species. Changing the morphology by creating macrophase separation elevated the IL uptake capacities, and in turn, increased their conductivities by a factor of three or more compared to Nafion 115. The stiffness of the membranes synthesized in this work was comparable to Nafion 115 and, thus, sufficient for practical applications.

Dataset Information

Preparation of exenatide-loaded linear poly(ethylene glycol)-brush poly(l-lysine) block copolymer: potential implications on diabetic nephropathy.

Publications

Preparation of exenatide-loaded linear poly(ethylene glycol)-brush poly(l-lysine) block copolymer: potential implications on diabetic nephropathy.

Similar Datasets

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