AIMTo study the morphology, particle size distribution and biological reliability of the norcantharindin (NCTD)-loaded microemulsion and pharmacokinetics of the W/O norcantharidin-loaded microemulsion in mice.

METHODSThe concentration of NCTD in plasma and tissues were determined by GC method. The data obtained were processed using 3P87 program.

RESULTSThe mean particle diameter of microemulsion was (44 +/- 9) nm. The concentration-time curve of NCTD-loaded microemulsion and NCTD injection was fitted to a two-compartment model. At the same dosage, the pharmacokinetic study for NCTD-loaded microemulsion showed the NCTD microemulsion had relatively longer circulating time in mice. Area under the curve of concentration versus time (AUC), mean residence time (MRT) and half life (T1/2) for microemulsion and injection were (29.7 +/- 0.9) mg x h x L(-1), (9.25 +/- 0.09) mg x h x L(-1), (110 +/- 11) h, (86.7 +/- 0.8) h, (103 +/- 12) h, (42 +/- 4) h, respectively. Targeting index of NCTD microemulsion in liver and kidney in mice were 0.43 and 0.12 after iv NCTD-loaded microemulsion. The effects of biological reliability was not significantly different between NCTD microemulsion and NCTD injection in vivo and in vitro.

CONCLUSIONThe liver targeting absorptive capability of NCTD-loaded microemulsion was enhanced and the release time was extended compared with NCTD injection. While the microemulsion vehicles could decrease the kidney distribution of NCTD.