[Studies on lung targeting gelatin microspheres of mitoxantrone]

Lung targeting gelatin microspheres of mitoxantrone (DHAQ) were prepared by a two-step method. The diameter of 87.36% of the DHAQ gelatin microspheres (DHAQ-GMS) was in the range of 5.1 to 25.0 microns. Release of the drug from the DHAQ-GMS in vitro became much slower and its t1/2 was 4 times longer than that of pure DHAQ. The characteristic peak of heat absorption on the differential thermal analysis curve was at 133 degrees C and almost no change was observed after the DHAQ-GMS were stored for 3 months at 37 degrees C (relative humidity 75%). The distribution test in vivo in mice indicated that the lung targeting effect of the DHAQ-GMS was obvious and that the targeting efficiency of the lung compared to other organs and blood increased 3 to 35 times. Kinetic behavior of the drug in mouse lung could be described by one open compartment model, and the average residual time increased by 10 h.