Distribution of a lipidic 2.5 nm diameter dendrimer carrier after oral administration

The biodistribution of a lipidic peptide dendrimer has been studied after o ral administration to female Sprague-Dawley rats (180 g, 9 weeks old). Upta ke by gut epithelial tissue of the radiolabelled dendrimer molecule (mol. w t. 6300; diameter 2.5 nm; log P = 1.24) was studied in rats after a single oral dose by gavage (14 mg/kg). The maximum levels of dendrimer observed we re 3% (blood), 1.5% (liver), 0.1% (spleen), 0.5% (kidneys), 15% (small inte stine) and 5% (large intestine). Approximately 6% of a single administered dose (28 mg/kg) was recovered from the entire gastrointestinal tract while 1% was absorbed via the small intestine lymphoid tissue after 3 h; after 12 h, 0.1% was detected. The maximum uptake by the non-lymphoid small intesti ne was 4% of the dose after 3 h. After 12 h, 0.3 and 4% dendrimer was measu red in the lymphoid large intestine and the non-lymphoid large intestine, r espectively. The total percentage of the administered dose absorbed through the lymphoid tissue was comparatively greater than through the non-lymphoi d tissue of the small intestine with respect to organ weight after 3 and 24 h. (C) 1999 Elsevier Science B.V. All rights reserved.