Azido-PEG-acid(Acid-PEG-Azide) is a type of compound that contains functional groups, specifically azido and carboxylic acid groups. These groups make it useful in pharmaceutical research and development as it can be used for a variety of applications such as drug delivery and bioconjugation. The azido group allows for facile click chemistry reactions with alkyne-containing molecules, while the carboxylic acid group can be used to conjugate to amine-containing molecules through peptide bond formation. Additionally, the presence of the PEG (polyethylene glycol) linker provides improved solubility and biocompatibility. Azido-PEG-acid is a versatile compound that can be used for various applications in pharmaceutical research and development.