Molecular imaging techniques to study the biodistribution of orally administered (99m)Tc-labelled naive and ligand-tagged nanoparticles.

<bold>Purpose: </bold>Study by molecular imaging the biodistribution of poly(anhydride) nanoparticles after oral administration.<bold>Procedures: </bold>Poly (anhydride) nanoparticles (NP) and cyclodextrin-tagged nanoparticles (CD-NP) were radiolabelled with (99m)Tc. Radiochemical purity was measured with a double-solvent chromatography system and the absence of undesirable components was confirmed by size and polydispersion measurement of the technetium-labelled nanoparticles by photon correlation spectroscopy. Single photon emission computed tomography (SPECT) fused computed tomography (CT) in vivo molecular imaging was used for biodistribution studies in small animals.<bold>Results: </bold>SPECT-CT images revealed activity only in the gastrointestinal tract. Thirteen percent of the given dose of CD-NP and 3% of the given dose of conventional NP were found in the stomach at 8 h.<bold>Conclusion: </bold>No evidence of translocation or distribution out of gastrointestinal tract was found. CD-NP moved significantly more slowly inside the gut than conventional NP, probably due to their physico-chemical structure that allows stronger interactions with the gut mucosa. [ABSTRACT FROM AUTHOR]