Indomethacin-loaded polyisobutylcyanoacrylate nanocapsules were prepared by interfacial polymerization of the alkylcyanoacrylate monomer. Mean particle size of the nanocapsules ranged from 200 to 300 nm. Comparison of the results following intravenous infusion of indomethacin solution and nanocapsules to rats revealed that nanoencapsulation accelerated the extravascular distribution of indomethacin due partly to enhanced uptake of the colloidal carrier by the liver reticuloendothelial system. Following intragastric administration, the oral bioavailability of indomethacin in solution was 90%--indicating complete absorption of this drug from the gastrointestinal tract of the rat. Absorption of indomethacin nanocapsules by this route was more rapid. This was attributed either to an increase in the intensity and/or the duration of contact of the encapsulated drug with the gut wall, or to a more efficient absorption process involving paracellular pathways.