Ref.
Yang G, Ge S, Singh R, Basu S, Shatzer K, Zen M, et al. (May 2017). “Glucuronidation: driving factors and their impact on glucuronide disposition”. Drug Metabolism Reviews. 49 (2): 105–138.
AxisPharm offers 5000+ PEG Linkers with high purity. Different kinds of PEG Reagents may be available by custom synthesis.