Using RESS to Make Particles | Supercritical Fluid

The formation of small nano or micro particles is an area of intense research. Small particles may possess different characteristics than larger molecules of the same substance. For example large ibuprofen particles in a crystalline form are difficult to absorb and are less bio available than smaller particles that can be created using supercritical fluids.

Supercritical fluids are used to create nano particles of drugs and other compounds using several techniques. The RESS technique (Rapid Depressurization of a Supercritical Solution) is used when a compound is soluble in supercritical CO₂. The compound is dissolved in supercritical CO₂ in a pressure vessel and subsequently discharged to atmospheric pressure through a nozzle into a collection chamber. During the rapid depressurization, the compounds are no longer soluble in gaseous CO₂, and they nucleate and precipitate forming many small particles. The particles are separated from the CO₂ gas at atmospheric pressure when the CO₂ gas passes through a filter inside the collector vessel.

Using the RESS technique large crystalline particles of Ibuprofen can be dissolved in supercritical CO₂ and reduced to a multitude of small non crystalline amorphous particles increasing their bio availability without the use of hazardous solvents.

For more information, see the Particles section of the website.