PEG-PGA Polyglutamic Acid

The structure of PEG-PGA (polyglutamic acid) enables controlled release of drugs. By adjusting the ratio and molecular weight of PEG to PGA, the rate and duration of drug release can be controlled to provide long-lasting drug delivery. BOC Sciences offers PEG-PGA products with a wide range of linkable groups, including COOH, NH₂, NHS, FA, and more.

What is PEG-PGA?

PEG-PGA is a grafted polymer and a new class of biodegradable polymers that are non-toxic and non-immunogenic to living organisms. It has no side effects and has good biocompatibility. Highly hydrophobic PGA combined with water-soluble PEG can form excellent drug delivery carriers. PEG-PGA derivatives are good drug cross-linking agents and drug delivery carriers, which can form a spatial barrier around the drug to reduce enzymatic hydrolysis of the drug, to avoid rapid elimination from the kidneys, metabolism, and to allow the drug to be recognized by the cells of the immune system.

Fig. 1. Synthetic route of γ-PGA-g-PLGA copolymer (European Polymer Journal, 2019, 110: 283-292).

Examples of PEG-PGA

(γ)PGA-PEG-(γ)PGA

(γ)PGA-PEG-(γ)PGA is a linear amphiphilic triblock copolymer containing carboxyl groups at both ends of the molecular chain. Poly-γ-glutamic acid (γ-PGA) is a polymer biopolymer consisting of glutamic acid repeating units with γ-amide bonds. γ-PGA is biodegradable, edible, water-soluble, and non-toxic to humans and the environment. (γ)PGA-PEG-(γ)PGA is a white powder or viscous liquid, depending on its molecular weight. The higher the molecular weight, the more likely it is to be a solid.

HS-PEG-(γ)PGA

HS-PEG-(γ)PGA is a linear amphiphilic block copolymer that can self-assemble into micelles. Among them, poly-L-glutamate serves as the hydrophobic part, and thioglutamyl-functionalized PEG serves as the hydrophilic part. The -SH group on the PEG chain can be reacted with biomolecules or small molecules containing the -MAL group. HS-PEG-(γ)PGA can be widely used as a drug carrier in targeted drug delivery systems.

MAL-PEG-(γ)PGA

MAL-PEG-(γ)PGA is a copolymer with MAL at one end and PGA at the other. MAL-PEG-(γ)PGA can be used to prepare drug-carrying microspheres, microcapsules, vesicles, and micelles, which enable slow controlled release of drugs. Polyglutamic acid polymerized with methionine, a drug used in the treatment of leukemia and tumors, can improve the efficacy of the drug. Thioether bonds formed by the reaction of maleimide and sulfhydryl groups at pH 6.5-7.5.

Modification of PEG-PGA

• Esterification Modification. Esterification modification involves the reaction of the carboxylic acid, hydroxyl group of PEG or PGA, which can be achieved by using an esterification reagent in a suitable solvent.
• Amine Modification. Amination modification uses a PEG molecule containing an amine functional group to react with a carboxylic acid functional group to form an amide bond linkage. Common amination reagents include diethylenediamine (DEA) and N,N'-bis(3-dimethylaminopropyl)carbodiimide (EDC).
• Thiolation Modifications. Thiolation modification involves the use of thiolating reagents to react with the carboxylic acid functional groups in PGA to form disulfide bond linkages.

Applications of PEG-PGA

• Anti-tumor Therapy. PEG-PGA can improve the efficacy of antitumor drugs by targeting tumor cells, increasing drug stability and improving drug bioavailability.
• Immunomodulation. The PGA segment of PEG-PGA enhances immune response by activating the immune system and promoting antigen presentation. This makes PEG-PGA copolymers promising for applications in immunotherapy and vaccine development.
• Bionanomaterials. The special structure and functionality of PEG-PGA makes it ideal for the preparation of bionic materials. The copolymer can be used to prepare artificial blood vessels, artificial organs, tissue repair membranes and other bionic materials to meet clinical needs.

BOC Sciences has strong manufacturing capabilities for PEG-PGA. We offer PEG-PGA derivatives with various linking groups to meet specific customer needs. We also provide technical support and expertise to help customers with PEG-PGA applications.

Reference

1. Hou, K.T. et al. DOX/ICG-carrying γ-PGA-g-PLGA-based polymeric nanoassemblies for acid-triggered rapid DOX release combined with NIR-activated photothermal effect. European Polymer Journal, 2019, 110: 283-292.