Determination Of Lipophilicity Research Articles

New challenge in the lipophilicity determination and separation of biologically active 16,17-secoesterone derivatives by HPLC – Use of pentafluorophenyl-propyl column

The retention behavior, lipophilicity of 16,17-secoestrone derivatives and efficiency in the separation of halogenated derivatives by HPLC with pentafluorophenyl-propyl stationary phase (F5) were studied. Methanol-water (MeOH-W) and acetonitrile-water (ACN-W) were used as mobile phases in proportions according to nomograph of iso-eluotropic binary solvent mixtures. Since mobile phase ACN-W was more effective eluent, the retention behavior of 16,17-secoesterone derivatives has further been evaluated, with water content increasing in increments of 5%. The retention constants log k for mobile phases MeOH-W and ACN-W, have been compared by applying Student’s paired t-test and Fisher’s F-test to determine the applicability of the nomograph to this column. Linear correlations were obtained between parameters log k0 and log P, as well as φ0 and log P, for both MeOH-W and ACN-W eluents. Compared with log k0, the hydrophobicity index φ0 proved to be better parameter for lipophylicity estimation of these compounds. According to the separation efficacy of individual components, as well as mixtures of halogenated secoestone compounds, chromatographic columns can be placed in the following order: C18> F5> C8. This result is of huge importance for the field of synthesis, purification and characterization of novel biologically and pharmacologically active compounds and steroids among them.

Lipophilicity and bio-mimetic properties determination of phytoestrogens using ultra-high-performance liquid chromatography.

This paper presents lipophilicity and bio-mimetic property determination of 15 phytoestrogens, namely biochanin A, daidzein, formononetin, genistein, genistein-4,7-dimethylether, prunetin, 3,4,7-trihydroxyisoflavon, 4,6,7-trihydroxyisoflavon, 4,6,7-trimethoxyisoflavon, daidzin, genistin, ononin, sissotrin, coumestrol and coumestrol dimethylether. High-performance liquid chromatography with fast gradient elution and Caco-2 cell line were used to determine the physicochemical properties of selected phytoestrogens. Lipophilicity was determined on octadecyl-sylane stationary phase using pH 2.0 and pH 7.4 buffers. Immobilized artificial membrane chromatography was used for prediction of interaction with biological membranes. Protein binding was measured on human serum albumin and α-1-acid-glycoprotein (AGP) stationary phases. Caco-2 assay was used as a gold standard for assessing in vitro permeability. The obtained results differentiate phytoestrogens according to their structure where aglycones show significantly higher lipophilicity, immobilized artificial membrane partitioning, AGP binding and Caco-2 permeability compared with glucosides. However, human serum albumin binding was very high for all investigated compounds. Furthermore, a good correlation between experimentally obtained chromatographic parameters and in silico prediction was obtained for lipophilicity and human serum albumin binding, while the somewhat greater difference was obtained for AGP binding and Caco-2 permeability.

Discovery of tropinone-thiazole derivatives as potent caspase 3/7 activators, and noncompetitive tyrosinase inhibitors with high antiproliferative activity: Rational design, one-pot tricomponent synthesis, and lipophilicity determination

We have designed novel tropinone-thiazole derivatives that showed high antiproliferative activity against a variety of cancer cell lines via caspase 3/7 activation mechanism. Among the derivatives, compounds 3b-3h were found to exhibit high activity against human leukemia (MV4-11), human lung carcinoma (A549), human breast carcinoma (MCF-7), and skin melanoma (B16–F10) cancer cell lines, with IC50 values of 5.43–11.06 μM. The lead compound 3g increases caspase 3/7 activity in A549 cells 25 times more than the control, and 2 times more than reference drug camptothecin. We have also found that tropinone-thiazole derivatives exhibit high tyrosinase inhibitory activity. The lead compounds 3g and 3h showed tyrosinase inhibition effect, with IC50 values 3.22 and 3.51 μM, respectively. These inhibitory activities are 22 times higher than the activity of kojic acid (IC50 72.27 μM) and 120 times higher than activity of ascorbic acid (IC50 386.5 μM). For compounds 3g and 3h, the experimentally determined lipophilicity correlates very well with their enzymatic activities. These data suggest that presented compounds could constitute lead anticancer drug candidates.

Thin-layer chromatography in medicinal chemistry

Among widely used chromatographic methods modern thin-layer chromatography is not only the simplest to perform but is also considered as respectable analytical method in various phases of drug discovery and development processes such as monitoring of synthesis, identification of bioactive substances from various natural sources and their isolation and purification, determination of lipophilicity and other physico-chemical parameters, quantitative structure-activity relationship studies, bioautography, as well as qualitative and quantitative analysis of drugs and their metabolites. An overview of recently published papers dealing with application of thin-layer chromatography in medicinal chemistry is presented.

Application of TLC for Evaluation of the Lipophilicity of Newly Synthetized Esters: Betulin Derivatives.

The problem of designing a new drug is nowadays very important for researches representing many branches of science. This work considers the usefulness of the analytical method such as thin-layer chromatography for the lipophilicity of newly synthesized compounds, betulin derivatives, which could be potential drugs with anticancer activity. The two mobile phases were used for the purpose of experimental determination of lipophilicity for mono- and diesters investigated. The first mobile phase consists of acetate and Tris buffer, whilst the second consists of 1,4-dioxane and acetate buffer. The value of the retardation factor was recalculation into the RM value, and then RM0 values were obtained by extrapolating acetone or 1,4-dioxane concentration to zero. The chromatographic data of lipophilicity were correlated with theoretically obtained values of ALOGPS, AClogP, miLogP, ALOGP, MLOGP, XLOGP2, and XLOGP3. The particular correlation equations were obtained. The cluster analysis was also used to find similarity between the esters investigated on the basis of the experimental or theoretical value of lipophilicity obtained. The good correlation between experimentally and theoretically calculated lipophilicity gives the possibility of prediction of this value on the basis of the correlation equation. On the basis of similarity analysis was stated strong connections between the structure and the value of lipophilicity, for both experimental and theoretical values.

Microplate assay for lipophilicity determination using intrinsic fluorescence of drugs: Application to a promising anticancer lead, pyridoclax

Lipophilicity must be necessarily determined in drug discovery since this physicochemical property will directly influence the pharmacokinetics of a drug as its pharmacodynamics profile. Pyridoclax is an original lead, recently identified as very promising in treatment of chemoresistant cancers. The partition coefficient (Kp) of this anticancer drug was determined by microplate assays, well adapted in drug discovery, since being rapid, and requiring only poor drug amounts. The analytical approach was performed either by UV derivative spectrophotometry after validation thanks to a set of basic, neutral and acid reference substances, or originally, by raw fluorescence spectrophotometry by taking advantage of the pyridoclax intrinsic fluorescence. Large unilamellar vesicles (LUVs) were formulated from soybean-, egg-, or dipalmitoyl-phosphatidylcholine, characterized in terms of granulometric properties, ζ potential (determined by DLS), and of phospholipid content (quantified by 1H NMR, also in presence of cholesterol). Whatever the detection method used, log Kp of pyridoclax were in the same magnitude order, and pyridoclax appeared as a lipophilic compound. It was also established that interactions between this lead and biomimetic membranes were influenced by the relative fluidity of the membranes, as confirmed by results of a liposome leakage assay.

A New Straightforward Method for Lipophilicity (logP) Measurement using 19F NMR Spectroscopy.

Fluorination has become an effective tool to optimize physicochemical properties of bioactive compounds. One of the applications of fluorine introduction is to modulate the lipophilicity of the compound. In our group, we are interested in the study of the impact of fluorination on lipophilicity of aliphatic fluorohydrins and fluorinated carbohydrates. These are not UV-active, resulting in a challenging lipophilicity determination. Here, we present a straightforward method for the measurement of lipophilicity of fluorinated compounds by 19F NMR spectroscopy. This method requires no UV-activity. Accurate solute mass, solvent and aliquot volume are also not required to be measured. Using this method, we measured the lipophilicities of a large number of fluorinated alkanols and carbohydrates.

Triazene salts: Design, synthesis, ctDNA interaction, lipophilicity determination, DFT calculation, and antiproliferative activity against human cancer cell lines

Synthesis, characterization and investigation of antiproliferative activity of nine triazene salts against human cancer cells lines (MV-4-11, MCF-7, JURKAT, HT-29, Hep-G2, HeLa, Du-145 and DAUDI), and normal human mammary epithelial cell line (MCF7-10A) is presented. The structures of novel compounds were determined using 1H and 13C NMR, and GC-APCI-MS analyses. Among the derivatives, compound 2c, 2d, 2e and 2f has very strong activity against biphenotypic B myelomonocytic leukemia MV4-11, with IC50 values from 5.42 to 7.69 µg/ml. The cytotoxic activity of compounds 2c-2f against normal human mammary gland epithelial cells MCF-10A is 6–11 times lower than against cancer cell lines. Our results also show that compounds 2c and 2f have very strong activity against DAUDI and HT-29 with IC50 4.91 µg/ml and 5.59 µg/ml, respectively. Their lipophilicity was determined using reversed-phase ultra-performance liquid chromatography and correlated with antiproliferative activity. Our UV–Vis spectroscopic results indicate also that triazene salts tends to interact with negatively charged DNA phosphate chain. To support the experiment, theoretical calculations of the 1H NMR shifts were carried out within the Density Functional Theory.

Incorporating physiologically relevant mobile phases in micellar liquid chromatography for the prediction of human intestinal absorption.

Micellar liquid chromatography is a popular method used in the determination of a compound's lipophilicity. This study describes the use of the obtained micelle–water partition coefficient (log P mw) by such a method in the prediction of human intestinal absorption (HIA). As a result of the close resemblance of the novel composition of the micellar mobile phase to that of physiological intestinal fluid, prediction was deemed to be highly successful. The unique micellar mobile phase consisted of a mixed micellar mixture of lecithin and six bile salts, i.e. a composition matching that found in the human intestinal environment, prepared in ratios resembling those in the intestine. This is considered to be the first method to use a physiological mixture of biosurfactants in the prediction of HIA. As a result, a mathematical model with high predictive ability (R 2 PRED = 81%) was obtained using multiple linear regression. The micelle–water partition coefficient (log P mw) obtained from micellar liquid chromatography was found to be a successful tool for prediction where the final optimum model included log P mw and polar surface area as key descriptors with high statistical significance for the prediction of HIA. This can be attributed to the nature of the mobile phase used in this study which contains the lecithin–bile salt complex, thus forming a bilayer system and therefore mimicking absorption across the intestinal membrane.

Synthesis, lipophilicity determination, DFT calculation, antifungal and DPPH radical scavenging activities of tetrahydrothiophen-3-one based thiazoles

Synthesis and investigation of antifungal activity of ten novel thiazoles derived from tetrahydrothiophen-3-one are presented. Among the derivatives, (E/Z)-2-(2-(dihydrothiophen-3(2H)-ylidene)hydrazinyl)thiazoles 3a-3d and 3h had very strong activity against reference strains of Candida albicans and Candida krusei with MIC = 0.24–3.91 μg/ml. Their lipophilicity was determined using reversed-phase high performance liquid chromatography and correlated with antifungal activity. Additionally, their DPPH radical scavenging activities was evaluated by spectrophotometric method. According to our results, compounds 3b, 3h and 3j have very strong antioxidant activities with IC50 values from 3.0 to 9.5 μg/ml. The antioxidant activity of these compounds is 5–17 times higher than butylated hydroxytoluene. The RP HPLC analysis revealed that the products are obtained as E/Z mixture in approximately 60:40 ratio, in good agreement with DFT predictions.

Lipophilicity determination of acidic compounds: MEEKC as a reliable high-throughput methodology

In the present study a pressure-assisted MEEKC method with reversed-polarity using a conventional CE instrument with UV detection and uncoated fused silica capillaries is validated as a high-throughput methodology for the lipophilicity determination of the neutral species of acidic compounds (pK<sub>a</sub> > 3.5). After the calibration of the system with four standard compounds of known log P<sub>o/w</sub>, mass distribution ratios (log k<sub>MEEKC</sub>) of new molecules can be directly converted into log P<sub>o/w</sub> values by means of a simple linear equation (log P<sub>o/w</sub>=a·log k<sub>MEEKC</sub>+b). The method was internally and externally validated for a log P<sub>o/w</sub> range between -1.54 and 4.75, with higher accuracies than conventional liquid chromatographic methods.

Prediction of in vivo Bioavailibility by in vitro Characterization of Ethylenediamine Dipropanoic Acid Derivatives with Cytotoxic Activity

O,O'-diethyl-(S,S)-ethylenediamine-N,N'-di-2-(3-cyclohexyl)propanoate (DE-EDCP) is novel substance with cytotoxic activity in human leukemic cells. The aim of this study has been to predict in vivo bioavailability of the DE-EDCP and its potential metabolite (S,S)-ethylenediamine-N,N'-di-2-(3-cyclohexyl)propanoic acid (EDCP) by in vitro characterization which includes determination of lipophilicity and passive membrane permeability. There has also been evaluated inter-laboratory reproducibility of the bio-analytical method which was previously developed and validated for non-clinical study of the DE-EDCP and EDCP. Distribution coefficient n-octanol/water was 1.68 and 0.03, and apparent permeability coefficient was 4 × 10-4 cm/s and 20 × 10-4 cm/s, for the DE-EDCP and EDCP, respectively. Observed results have shown that the DE-EDCP is more lipophilic with better membrane retention, but the EDCP has better pass through the membrane. Also, there has been demonstrated a reproducibility and robustness of the proposed bio-analytical method.

Synthesis and Determination of Lipophilicity, Anticonvulsant Activity, and Preliminary Safety of 3-Substituted and 3-Unsubstituted N-[(4-Arylpiperazin-1-yl)alkyl]pyrrolidine-2,5-dione Derivatives.

A new series of 1,3-substituted pyrrolidine-2,5-dione derivatives as potential anticonvulsant agents are described. Initial pharmacological screening of these compounds was performed by using acute models of seizures (MES and scPTZ tests) in mice after intraperitoneal administration. Quantitative pharmacological research revealed that the most promising compounds were N-[{4-(3-trifluoromethylphenyl)piperazin-1-yl}propyl]-3-benzhydrylpyrrolidine-2,5-dione monohydrochloride (11) with a ED50 value of 75.9 mg kg-1 (MES test) and N-[{4-(3,4-dichlorophenyl)piperazin-1-yl}ethyl]-3-methylpyrrolidine-2,5-dione monohydrochloride (18) with ED50 =88.2 mg kg-1 (MES test) and ED50 =65.7 kg mg-1 (scPTZ test). These compounds displayed a more beneficial protective index than well-known antiepileptic drugs. A plausible mechanism of action of compounds 11 and 18 [molecule 11 blocked the sodium channel (site 2) and 18 blocked both the sodium (site 2) and L-type calcium channels] and their preliminary safety in vitro were evaluated. Besides, the lipophilicity of all synthesized compounds was determined by using UPLC-MS.

The comparative study of micellar TLC and RP-TLC as potential tools for lipophilicity assessment based on QSRR approach

Lipophilicity of compound is well known as vital physicochemical property of a molecule, which determines its biological activity. Nonetheless, the assessment of a lipophilicity is still problematic and focuses attention of scientists. Although, the shake-flask method is still considered as a gold standard for experimental determination of lipophilicity, currently the chromatographic approach is mostly used. Among chromatographic methods used for lipophilicity assessment, thin layer chromatography (TLC) is still one of the most popular tools. The main goal of this study was to compare classical reversed-phase thin layer chromatography (RP-TLC) and micellar TLC as potential tools for lipophilicity assessment. Micellar liquid chromatography has significantly lover environment impact than classical reversed-phase liquid chromatography. Additionally comparison of cationic and anionic surfactants (CTAB and SDS), which have different chemical properties, as modifiers of mobile phase in micellar TLC were investigated. The Quantitative Structure–Retention Relationships (QSRR) approach was used in order to present molecular mechanisms of retention in investigated chromatographic systems. The study was based on chemically diverse model set compounds, with a proved therapeutic or toxic potential. According to obtained results the micellar TLC with CTAB as surfactant can be recommended to logP prediction. The obtained QSRR models indicated that adsorption of CTAB monomers on CN modified surface of silica gel and the silanol–quaternary ammonium interactions are possible. Consequently, the reduction of interaction between molecules and free silanol, contributes to the improvement of logP predictions. These result were confirmed by regression and classification methods.

Chemometrics approach based on chromatographic behavior, in silico characterization and molecular docking study of steroid analogs with biomedical importance

Physicochemical characterization of steroid analogs (triazole, tetrazole, toluenesulfonylhydrazide, nitrile, dinitrile and dione) is considered to be a very important step in further drug selection. This study applies to the determination of lipophilicity of previously synthesized steroid derivatives using reversed-phase high-performance liquid chromatography (RP HPLC). Chemometric aspect of chromatographic lipophilicity is given throughout multiple linear regression (MLR) quantitative structure-retention relationships (QSRR) approach. Minimal inhibitory concentration (MIC) is determined for two steroid derivatives possessing antimicrobial activity against Staphylococcus aureus. Molecular docking study was performed in order to identify the compound with the most promising potential as human cytochrome P450 CYP17A1inhibitor. Identified 3β-hydroxyandrost-5-eno[16,17-d]-1,2,3-triazole (I.2.) could be recommended for further trials for anticancer drugs and subjected to the absorption, distribution, metabolism, excretion and toxicity (ADMET) evaluation.

Unconventional TLC systems in lipophilicity determination: A review

ABSTRACTThis review focuses on four unusual thin-layer chromatography (TLC) approaches for the determination of lipophilicity: (1) the use of medium-polar stationary phases: CN, NH2, and DIOL instead of RP plates, together with water-based mobile phase; (2) the use of silica gel in a typical normal-phase manner and treating extrapolated retention indices as the “reversed lipophilicity”; (3) the use of oil impregnated silica gel in the reversed-phase manner; and (4) the use of salting-out mobile phases. The chromatographic indices obtained in these systems are numerously reported as well correlated with lipophilicity and they are an interesting alternative to classical RP systems approaches.

SYNTHESIS, CHARACTERIZATION, BIOLOGICAL EVALUATION AND DOCKING OF SOME NOVEL SUBSTITUTED 1, 3-THIAZINE DERIVATIVES

Objective: Chalcones and their heterocyclic analogs represent an important class of small molecules which have a wide range of pharmacological activities. Therefore, in this study, synthesis and anticonvulsant and antimicrobial activities of some new 1, 3-thiazines have been extensively discussed.Methods: The reaction mixture of 4-tert-butylcyclohexanone on Claisen-Schmidt condensation with various aromatic aldehydes in the presence of dilute sodium hydroxide afforded the corresponding chalcones. Further, these compounds were subjected to cocondensation with thiourea, in the presence of isopropanol, catalyzed by aqueous potassium hydroxide to form 4-aryl 8-arylidene-5, 6-dihydro-2-imino-6-methyl-4H, 7H-(1, 3) benzothiazines. The structures of the newly synthesized compounds have been established on the basis of their spectral analysis. The newly synthesized compounds have been tested for their biological screening. Antimicrobial activity by cup plate agar diffusion method and antiepileptic activity by pentylenetetrazole (PTZ) induced seizures model, using diphenyl hydantain as standard, and also they are subjected to molecular properties prediction, toxicity, drug-likeness, lipophilicity and solubility parameters determination were done by using Osiris program, Molsoft, Prototox and ALOGPS 2.1 software. The binding mode of the synthesized compounds with active protein site has been predicted using docking method.Results: Most of the compounds have shown good anticonvulsant as well as antimicrobial activities, but it is less than the standard drugs. 1, 3-thiazines derivatives were more potent, and among them, compounds TB5 andTB7 were the most active compounds in these series; TB5 whichcontains isopropyl phenyl moiety, was shown moderate potent activity with onset of convulsion at 14.1 min and TB7 containing 3, 4, 5-trimethoxyphenyl substituents on the thiazine moiety was more potent as it has prolonged the onset of convulsions by 18.7 min. Whereas in the case of antimicrobial activity of the compounds, from the results we have observed that TB5 have been shown greatest antimicrobial activity in all the bacterial and fungal strains, TB2 also shown superior activity, the others have been shown good antimicrobial activity.Conclusion: According to the activity studies, it is observed that the synthesis and antimicrobial as well as anticonvulsant activities of novel 1, 3-thiazine derivatives have been shown better activity. Moreover molecular docking results give an insight into how further modification of the lead compound can be carried out for higher inhibitory activity. In particular, compounds with electron withdrawing substituents along with lipophilic methoxyl and isopropyl groups were more potent.

Density functional theory calculation of lipophilicity for organophosphate type pesticides

Density functional method with continuum solvation model is used for calculation of partition coefficient logKOW and determination of lipophilicity of 22 most frequently used organophosphate type pesticides. Excellent agreement with experimental data is obtained using three different density functional approximations (one local, one general gradient and one hybrid), and our result highlights DFT as a reliable and trustworthy method for calculation and of lipophilicity for this important class of molecules. Furthermore, calculated lipophilicity results are associated with experimentally determined LD50 and LC50 values, showing that the most toxic pesticides are these with transient characteristics (medium lipophilicity), although this concussion must be taken with a caution due to the many factors influencing the ingestion and action of a certain substance in the body beside lipophilicity.

HPTLC and magnetochromatography of new complexes of carboxylates with transition metals or rare earth elements and their ligands - study of lipophilicity.

Nineteen new complexes of carboxylates with transition and rare elements as central ions and their ligands were characterized by chromatographic analyses. The parameter of relative lipophilicity (RM0 ) of the tested compounds was determined experimentally by the reversed-phase high-performance thin layer chromatography method with mixtures of various organic modifiers (acetonitrile, acetone, dioxane) and water as a mobile phase. The extrapolated RM0 values were compared with the logP values calculated from the molecular structures of tested solutes. Similarities between the lipophilicity indices were analysed by principal component analysis and linear regression. Thin-layer chromatography combined with a magnetic field has been proposed as a complementary method for determination of lipophilicity of the investigated compounds. The chromatograms in the field and outside it were developed simultaneously in two identical chromatographic chambers. One of them was placed in the external magnetic field of 0.4 T inductivity. We proved that chelation causes a drastic change in compound lipophilicity, but all complexes did not exhibit enhanced activity as compared with the parent ligand. Also in the magnetic field the retention of some complexes changed, which means that the presence of the field influences the physicochemical properties of the compounds and their interactions with the stationary phase.

Lipophilicity estimation and characterization of selected steroid derivatives of biomedical importance applying RP HPLC

The present paper deals with chromatographic lipophilicity determination of twenty-nine selected steroid derivatives using reversed-phase high-performance liquid chromatography (RP HPLC) combined with two mobile phase, acetonitrile-water and methanol-water. Chromatographic behavior of four groups (triazole and tetrazole, toluenesulfonylhydrazide, nitrile and dinitrile and dione) of selected steroid derivatives was studied. Investigated compounds were grouped using principal component analysis (PCA) according to their logk values for both mobile phases. Grouping was in the very good accordance with the polarity and lipophilicity of the investigated compounds. QSRR (quantitative structure-retention relationship) approach was used to model chromatographic lipophilicity behavior using molecular descriptors. Modeling was performed using linear regression (LR) and multiple linear regression (MLR) methods. The most influential molecular descriptors were lipophilicity descriptors that are important for molecules ability to pass through biological membranes and geometrical descriptors. All established LR-QSRR and MLR-QSRR models were statistically validated by standards, cross- and external validation parameters as well as with two graphical methods. According to all these assessments, MLR models were better for chromatographic lipophilicity prediction. It was shown that chromatographic systems with methanol-water were better for modeling of logk than systems with acetonitrile-water, as well as the systems that contained lower volume fractions of organic component in mobile phase. Modeling was performed in order to obtain lipophilicity profiles of investigated compounds as future drug candidates of biomedical importance.