Dynamics of polyelectrolyte complex formation and stability as a polyanion is progressively added to a polycation under modeled physicochemical blood conditions

Abstract

To understand the fate of anionic macromolecular species when injected into blood, poly(acrylic acid) and poly(L-lysine citramide) polyanions, with better charge densities, and the poly(L-lysine) polycation were used as models of negatively charged polymer—drug conjugates and positively charged blood proteins, respectively. To mimic an intravenous injection, the polyanion was added to the poly(L-lysine) stepwise at room temperature. The polyelectrolyte complexes formed as precipitates and the molar mass fractionation was observed from one fraction to the other, especially in the case of largely polydispersed poly(L-lysine). The salt concentration necessary to return each fraction of complexed polyelectrolyte back to solution varied linearly with the logarithm of the molar mass of the polycation component. The physicochemical characteristics data of the polyelectrolytes and the media are compared to previously reported reverse mixing mode when the polycation is introduced into a solution of polyanions.