CHARACTERIZATION OF COLLOIDAL DRUG CARRIERS - DETERMINATION OF SURFACE HYDROPHOBICITY BY HYDROPHOBIC INTERACTION CHROMATOGRAPHY

Hydrophobic interaction chromatography (HIC) is presented as a suitabl e method to determine the surface hydrophobicity of colloidal drug car riers. The experimental design is described in great detail. Results o btained with surface-modified polystyrene particles as model carriers and parenteral fat emulsions are discussed as examples. HIC was able t o distinguish between particles chemically modified by the introductio n of functional groups. Polystyrene particles of various size were sur face-modified by adsorption of the block-polymer Poloxamine 908. HIC d istinguished between the hydrophobicities of these adsorption layers. The measured surface hydrophobicities of particles and fat emulsions w ere well in agreement with the in vivo organ distribution data obtaine d after i. v. injection of the carriers.