Alkyne-PEG-Hydrazide[2]

Updated: 2026-09-12

Overview

Alkyne-PEG-Hydrazide is a heterobifunctional polyethylene glycol (PEG) derivative featuring terminal alkyne and hydrazide groups. This compound serves as a versatile linker in bioconjugation chemistry, particularly for connecting carbonyl-containing molecules via hydrazone bond formation while enabling subsequent click chemistry modifications through its alkyne moiety. The PEG spacer enhances water solubility and reduces steric hindrance in conjugation reactions. This reagent finds particular utility in pharmaceutical research, biomaterial engineering, and diagnostic probe development where controlled molecular assembly is required.

Physical and Chemical Properties

The compound typically appears as a white to off-white powder with good solubility in both aqueous and organic solvents including DMSO, DMF, and dichloromethane. Its physical properties vary significantly with PEG chain length (commonly n=4 to n=24 ethylene oxide units), affecting molecular weight (typically 300-2000 Da) and hydrodynamic radius. The alkyne group enables copper-catalyzed azide-alkyne cycloaddition (CuAAC) reactions, while the hydrazide moiety forms stable hydrazone bonds with aldehydes and ketones under mild acidic conditions. The PEG backbone provides excellent water solubility, non-immunogenicity, and resistance to protein adsorption.

Main Applications

In drug development, Alkyne-PEG-Hydrazide serves as a crucial linker for antibody-drug conjugates (ADCs), allowing sequential conjugation of cytotoxic payloads to antibody scaffolds. The hydrazide group specifically targets oxidized carbohydrate moieties on glycoproteins, while the alkyne permits subsequent functionalization. Material scientists employ this reagent for surface functionalization of nanoparticles and hydrogels. It's also used in diagnostic assay development for creating stable reporter molecule conjugates. Recent applications include bioorthogonal labeling strategies for live-cell imaging and the construction of PEGylated prodrug systems with controlled release profiles.

Safety and Storage

As a hygroscopic compound, Alkyne-PEG-Hydrazide requires strict moisture control during handling and storage. Recommended storage conditions include sealed containers under inert gas (argon or nitrogen) at -20°C, with desiccant packs to prevent hydrolysis of the hydrazide group. Personal protective equipment including nitrile gloves and safety goggles should be worn during handling. While not classified as highly toxic, the powder may cause irritation upon contact with skin or eyes. Work should be conducted in a well-ventilated area or fume hood, particularly when handling larger quantities.

B2B Procurement Guide

When sourcing Alkyne-PEG-Hydrazide, buyers should specify: (1) PEG chain length (molecular weight), (2) purity level (typically >95% for research grade, >98% for pharmaceutical applications), (3) endotoxin levels if for biological use, and (4) packaging requirements (often 100mg to 1g increments under argon). Lead times for custom PEG lengths may extend to 6-8 weeks. Reputable suppliers provide detailed NMR and HPLC characterization data. For GMP applications, request full documentation including certificate of analysis, stability data, and regulatory support files. Bulk quantities (100g+) may require special manufacturing campaigns.