Evaluation of ACE inhibitors lipophilicity using in silico and chromatographically obtained hydrophobicity parameters

Abstract

The aim of this study was to compare different calculation methods to determine lipophilicity, expressed as logP value, of seven ACE inhibitors (enalapril, quinapril, fosinopril, lisinopril, cilazapril, ramipril, and benazapril) with significantly different structure. Experimentally determined n-octanol/water partition coefficients, logPO/W values, were obtained from relevant literature. The correlations between all collected logP values were studied and the best agreements between calculated logP and experimentally determined logPO/W values, were observed for KOWWINlogP or MilogP values (r = 0.999 or r = 0.974, respectively). The correlations between all collected logP values and chromatographically (reversed-phase thin-layer chromatography) obtained hydrophobicity parameters, RM0 and C0, were established. The good correlations (r > 0.90) were obtained in the majority of relationships. The KOWWINlogP was established as the most suitable hydrophobicity parameter of investigated group of ACE inhibitors with r = 0.981 for correlation with RM0 and r = 0.977 for correlation with C0 parameters (water-methanol mobile phase). Using multiple linear regressions, it was established that application of two selected logP, calculated by different mathematical approaches, led to very good correlation due to the benefits of both calculation methods. The good relationships indicate that the computed logP, with careful selection of method calculation, can be useful in ACE inhibitors lipophilicity evaluation, as high-throughput screening technique.