RESS procedure

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The RESS process (Rapid Expansion of a Supercritical Solution) is a method for producing particles in the low micrometer range from organic and inorganic substances. Here, the substrate is dissolved in supercritical gas (mostly carbon dioxide ) and sprayed into a collecting container through a nozzle, where it is suddenly relaxed. Due to the pressure drop which is the limit of solubility of the substrate in the sc (supercritical) fluid sharply exceeded, because the fluid thereby passes out of the supercritical into the subcritical range, and falls out . This creates particles with a diameter of two to three µm.

Scheme of an RESS system. 1: compressor, 2: storage tank, 3: nozzle, 4: pressure equalization opening

The main advantage of this process is that a non-toxic, readily available and cheap solvent (CO 2 ) can be used. Since CO 2 has very favorable critical data (T C = 31 ° C, p C = 73.8 bar), the operating conditions for the RESS process are relatively moderate. Therefore, even thermally less resistant materials can be processed. In contrast to the PGSS process , the substrate does not have to be melted, but only has to be soluble in the sc fluid.

literature

  • PG Debenedetti et al .: Rapid expansion of supercritical solutions (ress): fundamentals and applications. In: Fluid Phase Equilibria. Volume 82, February 1993, pp. 311-321, doi : 10.1016 / 0378-3812 (93) 87155-T .
  • M. Türk et al .: Micronization of pharmaceutical substances by the Rapid Expansion of Supercritical Solutions (RESS): a promising method to improve bioavailability of poorly soluble pharmaceutical agents. In: The Journal of Supercritical Fluids. Volume 22, Issue 1, January 2002, pp. 75-84, doi : 10.1016 / S0896-8446 (01) 00109-7 .
  • Peter Hils: Production and stabilization of submicron organic active ingredients with the RESS process. Dissertation, University of Fridericiana Karlsruhe, 2009, urn : nbn: de: swb: 90-117255 , (PDF; 5.95 MB).

Individual evidence

  1. ↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics. 85th edition, CRC Press, 2004, ISBN 0-8493-0485-7 , pp. 6-53, ( limited preview in Google book search).