Nanoparticles derived from amphiphilic γ-cyclodextrins

Three alkylcarbonates of γ-cyclodextrin, i.e. hexyl, octyl and dodecylcarbonate, were synthesized and characterized, with the goal of formulating solid nanoparticles. The series of alkylcarbonates showed amphiphilic properties and were capable of forming micelles and nanoparticles. Blank and drug-loaded alkylcarbonate nanoparticles were prepared with each alkylcarbonate, using the solvent injection technique. Progesterone was chosen as model drug. The sizes of both unloaded and loaded nanoparticles were in the 80–200 nm range, with narrow size distribution and spherical shape, as shown by TEM analysis. The zeta potentials of unloaded nanoparticles were in the −20 to −24.0 mV range, and were slightly decreased in loaded nanoparticles. Drug-loading capacity was good; DSC analysis did not detect the progesterone melting peak, indicating the drug had interacted with the cyclodextrin alkylcarbonates. In vitro release kinetics of progesterone from the three types of nanoparticles were slow. These results indicate that γ-CD alkylcarbonate nanoparticles might be used as prolonged drug delivery system.