Gold Nanoparticles with Immobilized β-cyclodextrin-capsaicin Inclusion Complex for Prolonged Capsaicin Release

Abstract

Inclusion complexes of capsaicin with β-cyclodextrin (prepared at three different concentrations of β-cyclodextrin) were immobilized onto the surface of concentrated gold nanoparticles synthesized using the Frens method. Capsaicin release for 2 days into pure water and acetonitrile was recorded. The nanoparticles were characterized with absorbance spectra and transmission electron microscopy images. An inclusion complex without gold nanoparticles also displayed capsaicin release with a lag period of 1.5 days that suggested capsaicin release from gold nanoparticles was due to decomposition of the inclusion complex. Neither the inclusion complex nor the free capsaicin formed nanoparticles themselves. It was shown that physical immobilization of capsaicin onto the surface of gold nanoparticles without the aid of β-cyclodextrin did not lead to prolonged release. For comparison, inclusion complex encapsulation into chitosan nanoparticles was also carried out, but the release kinetics was less pronounced compared to that of gold nanoparticles.