Measurement and prediction of hydrophobicity parameters for highly lipophilic compounds: Application of the HPLC column-switching technique to measurement of log P of diarylpyrazines

Abstract

In the preparatory stage of structure-activity relationship (QSAR) studies of anti-platelet aggregant pyrazine derivatives, log P values (P: 1-octanol/water partition coefficient) of diarylpyrazines were measured by a newly developed HPLC column-switching technique. The system consists of two processes: (1) adsorption of the sample at the top end of a short precolumn, and then (2) quantifying the enriched analyte by a conventional analytical column. By using the log P values thus obtained, the correction factor for the steric hindrance caused by the vicinal diphenyl groups was estimated. The log k values (k; retention factor) were also measured with methanol-buffer (pH 7.4) eluents and related to log P. The eluent of 50% methanol content (M50) gave a good linear relationship over a wide range of log P (-0.3< log P < 5.2), indicating that log k(M50) parameter is useful for predicting the log P value.

Lipophilicity of some GABAergic phenols and related compounds determined by HPLC and partition coefficients in different systems

“…Nevertheless, log k C18 values correlated very well with all log k IAM values and with the partition coefficients in all systems including log P o/w . Some previous studies have revealed that the relationship between log P o/w and log k C18 usually requires some correction terms for hydrogenbonding effects [34]. It was observed that the hydrogen bond acidity strongly affects the reversed phase retention, but it does not have a significant effect on the n-octanol/water partition [12].…”

RP-HPLC determination of lipophilicity in series of quinoline derivatives

“…Molecules are transported through cellular membranes in organisms in similar environments. The lipophilicity data can be strongly influenced by intramolecular interactions under the applied chromatographic conditions [44][45][46][47]. Therefore, in this study, the measurements were performed using methanol to water (55:45) as the mobile phase.…”

“…The electronic effects from the bromine atom in the C (7) position compared to the electronic effects of bromine in the C (5) position differ in their influence on the vicinal phenolic oxygen [45][46] and influence the resultant lipophilicity of compound 11. These differences cannot be explained more precisely on the basis of the results presented here.…”

Design and Optimization of Self Nano-Emulsifying Drug Delivery System Containing a New Anti-inflamatory Agent Pentagamavunon-0

“…Although the solubility of PGV-0 in oleic acid was highest among the tested oils, it is still classified as very slightly soluble [14]. The solubility in oil is reflected by partition coefficient, logP, where logP > 3 means the compound is highly lipophilic [15]. Yuwono reported that apparent logP of PGV-0 was 1.84, so the solubility of PGV-0 in oils was low [16].…”