[Studies on anordrin injection for termination of early pregnancy in mice]

In order to increase the effectiveness on the termination of early pregnancy, anordrin injection was prepared. A nonaqueous solvent was selected as the parenteral solvent which was not irritating and toxic. The security test showed the injection was also not irritating and toxic. After the injection was heated for 76 h in 95 +/- 2 degrees C water or stored for 3 mon at 37 degrees C, the content of anordrin showed no change. The activation energy of the injection was 68.1 kJ/mol determined by thermogravimeter analysis. This also showed that the injection was steady. Results of termination of early pregnancy in mice showed that a single dose of anordrin injection (3 mg/kg) intraperitoneally was more effective than a single dose of anordrin tablet (3 mg/kg) orally (P less than 0.01). Histological studies showed that embryo, decidual cells and nutrient cells were markedly degenerated or dead when treated with the injection (3 mg/kg) intraperitoneally.