Abstract
Purpose. The objective of the work was to study the factors influencing the crystallisation of α-lactose monohydrate from aqueous solution using the Solution Enhanced Dispersion by Supercritical Fluids (SEDS) technique.
Methods. An aqueous solution of α-lactose monohydrate is dispersed with a homogeneous mixture of carbon dioxide-ethanol/methanol using a co-axial nozzle. Crystallised lactose particles were analysed for water content by Karl-Fisher analysis, anomeric composition by Differential Scanning Calorimetry (DSC) and characterised for crystallinity by powder X-ray diffraction and morphology by scanning electron microscopy.
Results. Water content in the lactose recrystallised with ethanol was higher compared to the product obtained with methanol as cosolvent. Rate of crystallisation could be altered by varying the CO2 flow thereby modifying the water content in the lactose. At low flow rates of CO2, the crystallisation occurred in a cosolvent rich antisolvent phase causing rapid crystallisation whereas high flow rates of CO2 favoured a much slower crystallisation mechanism in the water rich phase. As a consequence, the morphology changed from thin long bands to large agglomerated chunks with mean particle size between 5 and 31 microns.
Conclusions. The SEDS process is an efficient method for forming micron sized particles of water-soluble compounds with controlled physico-chemical properties.
Similar content being viewed by others
REFERENCES
M. McHugh and V. Krukonis. Special Applications. In Supercritical fluid extraction. Principles and practice. 2nd Edition. Butterworth-Heinemann, USA, 1994.
B. W. Muller and W. Fischer. German Patent No. DE 3744329 A1, (1989).
D. J. Dixon and K. P. Johnston. Formation of microporous polymer fibres and oriented fibrils by precipitation with a compressed fluid antisolvent. J. Appl. Polym. Sci. 50:1929–1942 (1993).
Yeo Sang-Do, Lim Gio-Bin, P. G. Debendetti, and B. Howard. Formation of microparticulate protein powders using a supercritical fluid antisolvent. Biotechnol. Bioeng. 41:341–346 (1993).
M. Hanna and P. York. Patent Application PCT/GB94/01426 (1994).
S. Palakodaty, M. Hanna, P. York, D. Rudd, and J. Pritchard. Particle formation using supercritical fluids—A novel approach. In Proc. 1997 ICheME Event, UK. ISBN: 0 85295 389 5, 1:501–504 (1997).
A. I. Semenova, E. A. Emel'yanova, S. S. Tsimmerman, and D. S. Tsiklis. Phase equilibria in the methanol-carbon dioxide system. Russ. J. Phys. Chem. 53:1428–1430 (1979).
M. L. McGlashan and A. G. Williamson. Isothermal vapourliquid equilibria for system methanol-water. J. Chem. Eng. Data. 21:196–199 (1976).
A. Z. Panagiotopoulos and R. C. Reid. High Pressure Phase Equilibria in Ternary Fluid Mixtures with a Supercritical Fluid. ACS Division of Fuel Chemistry Preprints. 30:46–56 (1985).
R. C. Pemberton and C. J. Mash. Thermodynamic properties of aqueous non-electrolyte mixtures II. Vapour pressures and excess Gibbs energies for water + ethanol at 308.15 to 363.15 K determined by an accurate static method. J. Chem. Therm. 10:867–888 (1978).
R. Wiebe. The binary system carbon dioxide-water under pressure. Chem. Rev. 29:475–481 (1941).
T. Sukune and G. C. Kennedy. The binary system H2O-CO2 at high temperatures and pressures. Amer. J. Sci. 262:1055–1074 (1964).
M. L. Gilbert and M. E. Paulaitis. Gas-liquid equilibrium for ethanol-water-carbon dioxide mixtures at elevated pressures. J. Chem. Eng. Data. 31:296–298 (1986).
J. S. Lim, Y. Y. Lee, and H. S. Chun. Phase equilibria for carbon dioxide-ethanol-water system at elevated pressures. J. Supercrit. Fluids. 7:219–231 (1994).
T. E. Chang and R. W. Rousseau. Solubilities of carbon dioxide in methanol and methanol-water at high pressures. Experimental data and modeling. Fluid Phase Equilibria. 23:243–258 (1985).
D. Y. Peng and D. B. Robinson. A new two constant equation of state. Ind. Eng. Chem. Fundam. 15:59–64 (1976)
R. E. Treybal. Mass-Transfer Operations, McGrawHill, USA, 1980.
M. Bichari, C. Roizard, A. Laurent, and N. Midoux. Determination of the volumetric gas-liquid mass transfer coefficients at pressures up to 5 MPa. In Ph. Rudolf von Rohr and Ch. Trepp (eds.), High Pressure Chemical Engineering, Process Technology Proceedings 12, Elsevier, 1996, pp. 169–174.
B. L. Herrington. Some physico-chemical properties of lactose. I The spontaneous crystallisation of supersaturated solutions of lactose. J. Diary Science. 17:501–534 (1934).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Palakodaty, S., York, P. & Pritchard, J. Supercritical Fluid Processing of Materials from Aqueous Solutions: The Application of SEDS to Lactose as a Model Substance. Pharm Res 15, 1835–1843 (1998). https://doi.org/10.1023/A:1011949805156
Issue Date:
DOI: https://doi.org/10.1023/A:1011949805156