Organ distribution of 5-fluorouracil loaded gelatine microspheres in mice

The aim of this study was to investigate the organ distribution characteristics of 5-fluorouracil (5-Fu) loaded crosslinked gelatine microspheres (5-Fu-MS) after intravenous (i.v.) injection compared to 5-Fu solution in mice, and to evaluate the targetability of 5-Fu-MS. The concentrations of 5-Fu in mice plasma, heart, liver, lung, kidney, spleen and brain were determined by HPLC. The parameters drug targeting index C-e, time-averaged relative drug exposure values r(e), drug targeting efficiency t(e), and drug distributed to target-tissue (%) were used to evaluate the targetability of the 5-Fu-MS delivery system. The results showed that the concentration of 5-Fu in the lung was significantly higher than after application of 5-Fu solution, and that the maximum concentration of 5-Fu, 72.8 mug (.) g organ(-1), was reached in the lung at 15 min after i.v. administration. As for 5-Fu-MS, r(e) was calculated to be 2.2, and t(e) was considerably higher than after application of 5-Fu in solution. Furthermore, the percentage of drug distributed to the lung was 2 times as high as after application in solution. Accordingly, 5-Fu-MS were capable of effectively delivering 5-Fu to the lung and possessed specific targetability towards the lung compared to 5-Fu solution.