Biodistribution of PLGA and PLGA/chitosan nanoparticles after repeat-dose oral delivery in F344 rats for 7 days

Aim: To quantify in vivo the biodistribution of poly(lactic-co-glycolic) acid (PLGA) and PLGA/chitosan nanoparticles (PLGA/Chi NPs) and assess if the positive charge of chitosan significantly enhances nanoparticle absorption in the GI tract. Material & methods: PLGA and PLGA/Chi NPs covalently linked to tetramethylrhodamine5- isothiocyanate (TRITC) were orally administered to F344 rats for 7 days, and the biodistribution of fluorescent NPs was analyzed in different organs. Results: The highest amount of particles (% total dose/g) was detected for both treatments in the spleen, followed by intestine and kidney, and then by liver, lung, heart and brain, with no significant difference between PLGA and PLGA/Chi NPs. Conclusion: Only a small percentage of orally delivered NPs was detected in the analyzed organs. The positive charge conferred by chitosan was not sufficient to improve the absorption of the PLGA/Chi NPs over that of PLGA NPs.