Particle generation, crystallization, encapsulation

Photo 1 : Active ingredient (rifampicin) precipitated using supercritical CO2 as an anti-solvent

The use of supercritical fluids (SCF) enables the development of clean and generally compact processes.

Among the various fields of application of SCFs, particle generation using supercritical CO2 (SC CO2) is a technique that has been studied for some thirty years and is already used in industry for certain applications. Compared with techniques using conventional solvents, the use of CO2 SC offers a number of advantages. It is a clean compound, whose specific properties (high density, low viscosity, low interfacial tension and higher diffusivity than liquids) are exploited for the recrystallization of compounds, enabling powders with controlled characteristics to be obtained. In addition, the use of CO2 SC simplifies the recrystallization process, as it separates spontaneously from the treated compounds by simple depressurization. Another advantage of CO2 is its low critical temperature (Tc=31.06°C), making it possible to operate in the supercritical phase under mild temperature conditions.

Photo 2 : Polymeric excipient (ethyl cellulose) precipitated using supercritical CO2 as an anti-solvent
The M2P2 Laboratory develops innovative processes for shaping active pharmaceutical ingredients (see photo 1), with the aim of forming controlled-release systems. Numerous academic (CSIR South Africa, University of Cadiz-Spain, University of Barcelona-Spain, University of Greenwich-UK) and industrial (MERCK Santé, FORMAC Pharmaceuticals, UCB Pharma) collaborations have enabled us to acquire real expertise in this field. The supercritical treatment of a large number of polymeric pharmaceutical excipients has been studied (see photo 2).

The Laboratory has recently initiated a new line of research involving the study of crystallization mechanisms in supercritical media, using molecular modeling software. The ultimate aim of this approach is to predict the characteristics of the powders formed as a function of the chosen operating conditions.