Continuous Supercritical Fluid Emulsion Extraction: A Low Impact Route for Biopolymer Microspheres Production

Continuous Supercritical Fluid Emulsion Extraction: A Low Impact Route for Biopolymer Microspheres Production

N. Falco * ^(a,b), E. Reverchon^(a) , G. Della Porta ^(a,c)

<>^(a) Dipartimento di Ingegneria Chimica e Alimentare, Università di Salerno, Fisciano (SA), Italy.

<>^(b) Department of Chemical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA, USA

^(c) Laboratorio di Ingegneria Cellulare e Molecolare, DEIS (sede di Cesena), Università di Bologna, Cesena (FC), Italy.

* Email: nfalco@unisa.it

ABSTRACT

Supercritical fluids can be used for extraction of the solvent from single and double emulsions such as oil-water (o-w) and water-oil-water (w-o-w), as a low environmental impact technology for the production of biopolymer microspheres with a controlled and narrow particle size. In particular, supercritical carbon dioxide (SC-CO₂) can diffuse and dissolve in the organic phase of the droplets and thereby function as an extracting solvent for the emulsion oily phase [1-4].  Supercritical emulsion extraction process, when carried out in a continuous operating mode (known as the SEE-C Process), is much faster than the conventional solvent evaporation/extraction processes. The process leads to the production of spherical microspheres with a controlled particle size distribution. The continuous extraction process eliminates the batch-to-batch variability and reduces the extraction time. Furthermore, it can be carried out at lower temperatures [5].

In this research, we are exploring the SEE-C technology for the production of biopolymer microparticles loaded with drug molecules. Poly(lactic-co-glycolic acid) (PLGA) microspheres charged with corticosteroid molecules using different o-w emulsions formed by ethyl acetate (EA) and water/polyvinyl alcohol (PVA) solutions have been prepared. PLGA microspheres with mean diameters between 3-5 mm were obtained at 80 bar and 38°C, operating with a flow-rate ratio of 1/10 for the liquid emulsion and supercritical carbon dioxide. At these conditions EA was completely miscible and extracted with SC-CO_2, whereas water was practically not soluble in SC-CO₂.

In this paper, we will present data on the particle size distributions, morphology and the properties of the drug loaded polymer microparticles, and discuss also the influence of supercritical carbon dioxide on the phase stability of the emulsion.

REFERENCES

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[2] B.Y. Shekunov, P. Chattopadhyay,  J. Seitzinger, R. Huff, Pharm. Res., Vol. 23(1), 2006, p. 196.

[3] G. Della Porta and E. Reverchon, Biotech. Bioeng., 2008, Vol. 100(5), p. 1020.

[4] G. Della Porta, N. Falco, E. Reverchon, J. Pharm. Sci., 2010, Vol. 99(3), p. 1484.

[5] G. Della Porta, N. Falco, E. Reverchon, Biotech. Bioeng, 2010, DOI 10.1002/bit.22972.