Interactions of sol-gel encapsulated acyclovir with silica matrix.

Encapsulation of drugs is promising strategy to improve their pharmacological and consumer properties. The functional properties of the encapsulated drug depend on interactions between the drug and capsule material. Antiviral drug acyclovir (ACV) was encapsulated in silica matrixes using sol-gel technology. The effects of synthesis pH and the silica matrix functionalization by organic groups on the drug - silica matrix interaction were studied. The interactions were investigated using UV/VIS spectroscopy and Fourier-transform infrared (FTIR) spectroscopy. The nature of the interactions in the obtained composites was discussed. It was found that the drug self-association in some composites can be provoked by electrostatic repulsion between the drug and the silica matrix.