We wanted to present a proof of concept that the disulfide bond can be reduced in the presence of a reducing agent, while also identifying the resulting degradation products. hPG10-DTDPA, referred to as SS-hPG throughout the remainder of this manuscript, was incubated in an aqueous solution containing 10 mM of 3,3′,3′′-Phosphanetriyltripropanoic acid (TCEP) as reducing agent to cleave the disulfide bonds. After 3 days, 1 H NMR was used to identify the resulting degradation products (Figure ). In the 1 H NMR of degradation products, the peak at 3.0 ppm, assigned to the methylene protons adjacent to the disulfide bond, disappeared, while a new peak appeared at 2.9 ppm, which is assigned to the methylene protons adjacent to thiol groups. Hence, our degradation products are a polyglycerol chain with a free thiol group, a polyglycerol chain completely detached from DTDPA due to the ester cleavage, and 3-mercaptopropanoic acid resulting from the cleavage of both ester and disulfide groups.