Polyelectrolyte Complexes of Chitosan with Sodium Carboxymethyl Cellulose in Water–Alcohol Media and Microcapsules Based on Them

The formation of polyelectrolyte complexes between natural polysaccharides, chitosan and carboxymethyl cellulose sodium salt, in water–ethanol media was studied. It was found that, with an increase in the content of ethanol in the solvent to 50 vol %, the intensity of the Coulomb interactions between oppositely charged groups of polyelectrolytes gradually weakens and, as a consequence, the complexing ability of polymers decreases. The layer-by-layer adsorption of polyelectrolytes onto calcium carbonate microparticles yielded microcapsules with a different number of layers. An approach is proposed to control the permeability of polyelectrolyte microcapsule walls by changing the solvent polarity upon addition of 50 vol % ethanol to an aqueous solution. Microcapsules with a high efficiency of inclusion of a model drug substance, acetylsalicylic acid, were obtained using this approach.