Patent ID: 9127168
Filing Date: 2015-09-08
Classification: A61K,A61P,B82Y,C01G,C01P,C09C

Abstract:
1. A process for producing magnetic iron oxide fine particles, the magnetic iron oxide fine particles having a primary particle diameter of 5 to 15 nm and an average secondary particle diameter of 10 to 60 nm, a surface of the respective magnetic iron oxide fine particles being coated with a carboxyl group-containing polymer, the process comprising the steps of: heating an aqueous solution in which the carboxyl group-containing polymer is dissolved, to a temperature of 90 to 100° C. in a nitrogen atmosphere; adding a solution of a ferrous (II) salt and a ferric (III) salt and an alkali solution to the aqueous solution to react with each other at the same temperature; adding ethanol to the resulting solution to obtain a precipitate; removing a supernatant liquid from the solution, and then dispersing the precipitate in water and subjecting the resulting dispersion to dialysis to obtain a water dispersion comprising the magnetic iron oxide fine particles whose surface is coated with the carboxyl group-containing polymer; and freeze-drying the water dispersion to obtain the magnetic iron oxide fine particles.