Self-Assembly of Colloidosome Shells on Drug-Containing Hydrogels

Abstract

Colloidosomes are composed of an aqueous or hydrogel corethat is coated by a semi-permeable colloidal shell. The properties of the shell can be varied to control the rate of release of encapsulated components such as drugs. Specifi-cally, the pores formed between the colloidal particles suppress transport of large components, while allowing diffusion of smaller ones. Self-assembly of colloidal particles on hydrogel films is a convenient method forcolloidosome synthesis, but to date little is known regarding the effect (if any) of the encapsulated drug on the shell packing density. In this paper we examined self-assembly of colloidal shells on alginate films containing four model drugs: aspirin, caffeine, theophylline and theobromine. We find that the packing density in the colloidal shells is low for all drugs, and ranges between 0.16 and 0.3. There is no clear correlation between drug properties (in particular, water solubility) and the packing density of the self-assembled colloidal shell.