Influence of solubility and partition coefficient on the loading of combined poly(isobutylcyanoacrylate) and hydroxypropyl-beta-cyclodextrin nanoparticles by steroids

Combined poly(isobutylcyanoacrylate) and cyclodextrin nanoparticles have re cently been prepared by polymerization of the monomer in the presence of cy clodextrins. The association of large amounts of cyclodextrins with particl es was likely to modify not only loading of the particles during the polyme rization process but also the lipophilicity of the polymer, because of intr oducing numerous lipophilic sites into the particle structure. In a series of corticosteroids spanning a broad range of water solubility and lipophili city values, it has been shown that drug loading of combined nanoparticles were increased up to 120-fold when compared to standard poly(isobutylcyanoa crylate) particles. The ability of the drug to achieve a high level of part icle loading depended both on the drug concentration in the polymerization medium and on the octanol-water partition coefficient. It was therefore con cluded that the drug loading of the combined nanoparticles was driven by th e partition equilibrium between the polymeric structure and the polymerizat ion medium.