Aqueous suspension of nanoscale drug particles from supercritical fluid processing
Document Type Patent
The present invention is directed to an improved supercritical fluid processing technique that can be used to form particulate suspensions of biologically useful materials. The disclosed processes include variations of RESS processes. The disclosed processes do not form micelles of any stabilizing agents in the aqueous solution that receives the product materials following rapid expansion through a nozzle. In particular, stabilizing agents in the aqueous solution are either materials that will not form micelles in aqueous environments, or else they are materials that can form micelles, but are utilized at conditions that are insufficient for the formation of micelles or at least not suitable for any significant presence of micelles in the product. Through utilization of the disclosed process, particulate suspensions can be formed exclusively of very small particles, for example, particulate suspensions in which all of the particles formed are less than 100 nm in size. Moreover, the product suspension of particles can be very homogeneous, with particle size distribution standard deviations of less than about 15 nm.