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Updated: Oct 17, 2025

Fabrication of Pulsatile Polymeric Microparticles Encapsulating Rabies Antigen
Published on: May 12, 2023
Application of a caprylate/chromatography purification process for production of a high potency rabies immune
Michelle Woznichak1, Pete Vandeberg1, Catherine Russ1
1Grifols Bioscience Research & Development, Scientific Innovation Office, 85 TW Alexander Drive, Research Triangle Park, NC 27709, USA.
Background:
Human rabies immunoglobulin (RIG) is an integral part of post-exposure prophylactic treatment of rabies (along with rabies vaccination). Infiltration of most, if not all, of the RIG dose at the wound site is recommended. RIG produced by a caprylate/chromatography manufacturing process (RIG-C; HyperRAB) increased the potency and purity of this product over the existing licensed RIG from a solvent/detergent process (RIG-S/D; HyperRAB-S/D).
Methods:
A series of studies were conducted to characterize the content and purity of RIG-C. A single-dose pharmacokinetic study in rabbits was performed to compare intramuscular (IM) immunoglobulin products manufactured by two different purification processes, solvent/detergent (IGIM-S/D) and caprylate/chromatography (IGIM-C).
Results:
RIG-C was found to be a highly purified IgG formulation with high monomer content and formulated with twice the anti-rabies potency of RIG-S/D while maintaining the same overall protein concentration. RIG-C facilitates IM administration at the wound site by halving the injection volume. The new caprylate/chromatography process eliminated detectible levels of pro-coagulant impurities and IgA that were carried through in the prior S/D process. These impurities have been associated with thrombotic complications and allergic reactions in susceptible patients. After single dose administration, IGIM-C was pharmacokinetically equivalent to IGIM-S/D in rabbits.
Conclusion:
RIG-C is a more potent RIG formulation with less impurities yielding a safer and more convenient product with similar pharmacokinetic profile.

