Encapsulation of caffeine in polysaccharide oil-core nanocapsules

Nanoemulsion droplets stabilized with a polysaccharide multilayer film were used as carriers for caffeine. Multilayered shells were formed through a subsequent layer-by-layer adsorption of oppositely charged chitosan and alginate (sodium salt) onto emulsion droplets or oil-core nanocapsules at low ionic strength. The hydrophilic positively charged molecules of the drug were impregnated into the film after each alginate layer. The experimental results showed dependence of the encapsulation efficiency of caffeine on the number of the adsorbed polymer layers and on the properties of chitosan used for formation of the film (molecular weight and degree of acetylation). Despite the low encapsulation efficiency of the drug into the capsules (~ 40%) compared with other encapsulation systems, the amount loaded into the film was high enough and pharmacological doses were achieved with very small volumes of the dispersion.