Application of supramolecular technology for the delivery of erythropoietin: Synthesis of β-cyclodextrin-Erythropoietin inclusion complex via a host-guest interaction

Recombinant human erythropoietin (rhEPO) is an important therapeutic protein that is used to treat anemia. To improve the pharmacokinetic properties of proteins, structure modification with PEG molecules has been considered as a promising approach. However, PEGylation has been found to reduce the bioactivity of proteins. To overcome this challenge, a recently developed Self-assembly PEGylation Retaining Activity (SPRA) technology has been proposed to increase the blood retention of proteins without loss of activity. In this investigation, we used this approach and synthesized SPRA-rhEPO inclusion complex via a host-guest interaction. The inclusion complex was prepared by reacting adamantane (AD) modified rhEPO and monoPEGylated beta-cyclodextrin (beta-CD) with a molar ratio of 1:1. Different analytical techniques including FT-IR, powder XRD, 1H NMR spectroscopy, TGA, DSC, and MALDI-TOF mass spectrometry were employed and the results confirmed the formation of the inclusion complex.