Nano Archive

New magnetic nano-absorbent for the determination of n-octanol/water partition coefficients

Gao, X and Yu, C. H. and Tam, K. Y. and Tsang, S. C. (2005) New magnetic nano-absorbent for the determination of n-octanol/water partition coefficients. Journal of Pharmaceutical and Biomedical Analysis, 38 (2). 197 - 203.

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A novel and generic miniaturization methodology for the determination of partition coefficient values of organic compounds in n-octanol/water by using magnetic nanoparticles is, for the first time, described. We have successfully designed, synthesised and characterised new colloidal stable porous silica-encapsulated magnetic nanoparticles of controlled dimensions. These nanoparticles absorbing a tiny amount of n-octanol in their porous silica over-layer are homogeneously dispersed into a bulk aqueous phase (pH 7.40) containing an organic compound prior to magnetic separation. The small size of the particles and the efficient mixing allow a rapid establishment of the partition equilibrium of the organic compound between the solid supported n-octanol nano-droplets and the bulk aqueous phase. UV–vis spectrophotometry is then applied as a quantitative method to determine the concentration of the organic compound in the aqueous phase both before and after partitioning (after magnetic separation). log D values of organic compounds of pharmaceutical interest (0.65–3.50), determined by this novel methodology, were found to be in excellent agreement with the values measured by the shake-flask method in two independent laboratories, which are also consistent with the literature data. It was also found that this new technique gives a number of advantages such as providing an accurate measurement of log D value, a much shorter experimental time and a smaller sample size required. With this approach, the formation of a problematic emulsion, commonly encountered in shake-flask experiments, is eliminated. It is envisaged that this method could be applicable to the high throughput log D screening of drug candidates.

Item Type:Article
Uncontrolled Keywords:Magnetic nanoparticle; Partition coefficient; Magnetic separation
Subjects:Material Science > Nanofabrication processes and tools
Physical Science > Nanomagnetics
Material Science > Nanostructured materials
Biomedical Science > Nanomedicine
ID Code:5821
Deposited By:SPI
Deposited On:07 Jul 2009 16:47
Last Modified:07 Jul 2009 16:47

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