Characterization and Prediction of Partition Coefficients of Uncharged Solutes into Micelles and Liposomes using Electrokinetic Chromatography

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2002-12-06

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Abstract

Liposome and micelle electrokinetic chromatography (EKC) were used to determine retention factors (k) that are directly related to partition coefficients (K) and the phase ratio (φ) as: k = K*φ. Linear solvation energy relationship (LSER) models were used to elucidate the contributions of solute partitioning into liposomes. In addition, an LSER model for both MEKC and LEKC was used to determine partition coefficients for solutes without observed partition coefficients. The observed partition coefficients and those determined from LSER were then used to predict partition coefficients with the group contribution approach (GCA) and the fragmental constant approach (FCA) from solute structure. In the GCA, a relatively small number of key monosubstituted aromatic and aliphatic solutes are used to determine the substituent constants of functional groups. These substituent constants as well as the contributions from aromatic and aliphatic carbon plus hydrogen are used to predict partition coefficients of other solutes. Though the GCA is able to predict partition coefficients for simple di-substituted aromatics, predictions for more complicated solutes such as drugs are considerably less accurate. In the FCA, a large database of aromatic and aliphatic solutes is used to determine the fragmental constants of various functional groups as well as carbon and hydrogen. Overall, the FCA was able to predict partition coefficients for more complicated solutes like drugs with more accuracy than the GCA. However, with both the GCA and FCA large solute databases are needed because they are relatively small (˜ 500) in comparison to the 8,000 aromatic and aliphatic solutes analyzed with the octanol-water system.

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MEKC, LEKC, LSER, SDS

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http://www.lib.ncsu.edu/resolver/1840.16/4568

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PhD

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Chemistry

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