| abstract |
A sterile product containing a substance embedded in a carrier is produced by use of a supercritical gas. In one embodiment, a mixture is formed of a substance, carrier and supercritical gas such as nitrous oxide or carbon dioxide, and the supercritical gas is separated from the substance and carrier to obtain the product. In another embodiment, the supercritical gas contains the substance, and is mixed with an atomized organic solvent containing the carrier to form a mixture. The supercritical gas extracts the solvent, and is separated from the substance and carrier to produce the product. Alternatively, the carrier can be in the supercritical gas and the substance in the solvent, or both the substance and carrier can be in the solvent. Atomization and formation of the mixture can be carried out by feeding the supercritical gas and solvent through a nozzle into a spray tower or column. The supercritical gas containing the solvent is separated to obtain the product in the form of a dry powder containing spheres of the carrier having the substance embedded therein. The carrier can be polymers, lipids, lecithins or waxes, and the substance can be medicines, toxins, viruses, diagnostic materials, herbicides, insecticides or pesticides. An apparatus for carrying out the method contains a spray tower and other means for performing the method steps. |