This paper is to establish a reversed-phase ion-pair chromatography (RP-IPC) method for universal estimation of the octanol/water partition coefficients (logP) of a wide range of structurally diverse compounds including acidic, basic, neutral and amphoteric species. The retention factors corresponding to 100% water (logk(w)) were derived from the linear part of the logk'/phi relationship, using at least four isocratic logk' values containing different organic compositions. The logk(w) parameters obtained were close to the corresponding logP values obtained with the standard "shake flask" methods. The mean deviation for test drugs is 0.31. RP-IPC with trifluoroacetic acid as non classic ion-pair agents can be applicable to determine the logP values for a variety of drug-like molecules with increased accuracy.
1-Octanol ; chemistry ; Chromatography, Reverse-Phase ; methods ; Hydrogen-Ion Concentration ; Octanols ; chemistry ; Trifluoroacetic Acid ; Water ; chemistry

AIMTo investigate the interaction between drugs and ordered phospholipid membrane using immobilized artificial membrane chromatography (IAMC).

METHODSIAMC was used to determine the interaction drugs with phospholipid membrane, expressed as membrane affinity (lg kIAM). An n-octanol/buffer system was also employed as the reference hydrophobicity (lg Do/w,7.4).

RESULTSWithin the range of used acetonitrile percentages (phi) 0-30% in mobile phase, retention index (lg kIAM) showed excellent correlation with phi. Intercepts of fitted straight lines between lg kIAM and phi were comparable but slopes were much different for the three organic modifiers (acetonitrile, ethanol and methanol). Effects by adding CH2 substituent on lipophilicity difference (delta lg kIAM and delta lg Do/w,7.4) were similar for p-hydroxyl benzoic methyl ester to butyl ester, whereas different for p-hydroxylbenzoic acid to methyl ester.

CONCLUSIONIAMC system is a convenient, efficient and rapid tool for determining membrane interaction.

Membranes, Artificial ; Octanols ; chemistry ; Pharmaceutical Preparations ; chemistry ; Phospholipids ; chemistry

The HPLC and TLC retention, n-octanol/water partition coefficients (log Kow), bioconcentration factors, and acute toxicity data of 29 heteroatomic polycyclic aromatic hydrocarbons and 7 parent polycyclic aromatics were determined experimentally. For the same set of compounds, molecular weights, fragmental log Kow values, and molecular connectivities were calculated. Quantitation of the mathematical relationships between the variables was used to validate the predictive potential of various parameters. The importance of log Kow in predictive studies is highlighted. It is concluded that the internal concentration of a pollutant in the organism should be used as a parameter in future QSAR work.
1-Octanol ; Animals ; Chromatography, High Pressure Liquid ; Chromatography, Thin Layer ; Daphnia ; drug effects ; Ecology ; Environmental Pollution ; prevention & control ; Octanols ; Photobacterium ; drug effects ; Poecilia ; metabolism ; Polycyclic Compounds ; metabolism ; toxicity ; Regression Analysis ; Solubility ; Structure-Activity Relationship ; Water

The national standards of biofuels specify the technique specification and analytical methods. A water content certified reference material based on the water saturated octanol was developed in order to satisfy the needs of the instrument calibration and the methods validation, assure the accuracy and consistency of results in water content measurements of biofuels. Three analytical methods based on different theories were employed to certify the water content of the reference material, including Karl Fischer coulometric titration, Karl Fischer volumetric titration and quantitative nuclear magnetic resonance. The consistency of coulometric and volumetric titration was achieved through the improvement of methods. The accuracy of the certified result was improved by the introduction of the new method of quantitative nuclear magnetic resonance. Finally, the certified value of reference material is 4.76% with an expanded uncertainty of 0.09%.
Biofuels ; standards ; Magnetic Resonance Spectroscopy ; methods ; Octanols ; chemistry ; Reference Values ; Water ; analysis

AIMTo compare lipophilicity measuring scale stemmed from immobilized artificial membrane chromatography and n-octanol/buffer systems.

METHODSA test set consisted of 27 structurally diverse compounds. The lipophilicity of these were evaluated by both immobilized artificial membrane chromatography (IAMC) and n-octanol/buffer systems, which were expressed as lg kIAM and lg DO/W,7.4, respectively.

RESULTSWith regard to each individual group, good correlation coefficient (r2) over 0.81 was obtained (0.82 for acid; 0.88 for neutral, 0.81 for base and 0.92 for ampholyte, respectively). However, a smaller r2 (0.62) was acquired for all compounds studied than that of each individual group.

CONCLUSIONIAMC and n-octanol/buffer systems were shown to be different in lipophilicity.

Buffers ; Chromatography, High Pressure Liquid ; methods ; Hydrophobic and Hydrophilic Interactions ; Lipids ; chemistry ; Membranes, Artificial ; Octanols ; chemistry ; Pharmaceutical Preparations ; chemistry ; Phospholipids ; chemistry

AIMTo analyze and compare the compositions in essential oils from branches and leaves of Rhododendron simsii Planch. and Rhododendron naamkwanense Merr.

METHODSEssential oils were extracted by water distillation according to Chinese Pharmacopoeia and analyzed by capillary gas chromatography-mass spectrometry as well as chemometrics resolution method and authentic compounds. The relative contents of each component in the essential oils were obtained by normalization of peak areas.

RESULTSA total of 124 components were identified, of which 48 compounds were existed in both of the samples. Ninety four compounds accounted for 84.47% of the essential oil from Rhododendron simsii Planch. and seventy eight components accounted for 90.25% of the total essential oil from Rhododendron naamkwanense Merr. were identified. 72.76% and 88.07% of the components in Rhododendron simsii Planch and Rhododendron naamkwanense Merr., respectively, included oxygen element. They are mainly terpenol, acids and esters. 1-octen-3-ol (4.00%, 7.90%), 1,6-octadien-3-ol, 3,7-dimethyl-(12.60%, 3.48%), 9,12,15-octadecatrienoic acid, [Z, Z, Z]- (1.15%, 45.34%), phytol (15.21%, 8.56%), p-menth-1-en-8-ol (2.15%, 3.29%), and 9,12,15-octadecatrienoic acid, ethyl ester, [Z,Z,Z]- (9.16%, 8.01%) were their common main compounds, which accounted for 44. 27% and 76.58% of the total amount of the two essential oil samples, respectively. In addition, n-hexadecanoic acid (7.73%), 9,12-octadecadienoic acid (1.85%) and tetracosanoic acid, methyl ester (1.38%) were also the main compounds in essential oil from Rhododendron simsii Planch.

CONCLUSIONMuch higher reliability and accuracy were obtained with the help of chemometrics resolution method and authentic n-alkane standard solutions than those of using GC-MS alone.

Linoleic Acid ; analysis ; Octanols ; analysis ; Oils, Volatile ; chemistry ; isolation & purification ; Palmitic Acid ; analysis ; Phytol ; analysis ; Plant Leaves ; chemistry ; Plant Oils ; chemistry ; isolation & purification ; Plant Stems ; chemistry ; Plants, Medicinal ; chemistry ; classification ; Rhododendron ; chemistry ; classification ; Terpenes ; analysis

OBJECTIVETo study the chemical constituents of the volatile oil from the aerial parts of Isodon eriocalyx var. laxiflora.

METHODThe oil was obtained by hydrodistillation. The chemical compositions were separated and identified by GC-MS. The relative contents in the oil were determined by area normalization.

RESULT163 peaks were separated and 105 compounds were identified, constituting 85.68% of the total peak area.

CONCLUSION105 compounds characterized by GC-MS analysis were found from I. eriocalyx var. laxiflora for the first time.

Gas Chromatography-Mass Spectrometry ; Hexanols ; analysis ; isolation & purification ; Isodon ; chemistry ; Octanols ; analysis ; isolation & purification ; Oils, Volatile ; chemistry ; isolation & purification ; Phytol ; analysis ; isolation & purification ; Plant Components, Aerial ; chemistry ; Plants, Medicinal ; chemistry

OBJECTIVETo investigate the role of connexin 43-formed hemichannels in cell volume regulation induced by simulated ischemia/reperfusion (SI/R).

METHODSMouse cardiomyocytes isolated on a Langendorff apparatus with enzyme solution were aliquoted into control, SI/R and SI/R +octanol groups. Calcein-AM was used to stain the cells and the cell volume was measured with confocal microscope by stack scanning. Trypan blue was used to measure the cell viability after the treatments.

RESULTSCalcein-AM staining and cofocal microscopy yielded stable and reproducible results for cell volume measurement. Mouse cardiomyocytes subjected to simulated SI/R showed obvious cell swelling as compared with the control cells [(126∓6)% vs 100%, P<0.05], and octanol preconditioning significantly attenuated the cell swelling [(113∓6)%, P<0.05]. SI/R caused a significant reduction of the cell viability compared to the control cells [(19∓2)% vs (45∓3)%, P<0.01], and octanol preconditioning obviously reduced the viability of the cells with SI/R challenge [(31∓2)%, P<0.01].

CONCLUSIONConnexin 43-formed hemichannels are involved in the regulation of cardiomyocyte volumes induced by SI/R challenge, and octanol can alleviate the cell swelling to enhance the viability of the cardiomyocytes following SI/R.

Animals ; Cell Line ; Cell Size ; Cell Survival ; Connexin 43 ; metabolism ; Ischemic Preconditioning, Myocardial ; methods ; Mice ; Mice, Inbred C57BL ; Myocardial Reperfusion Injury ; metabolism ; pathology ; Myocytes, Cardiac ; drug effects ; pathology ; Octanols ; pharmacology

BACKGROUND AND OBJECTIVES: Using n-aliphatic alcohols whose physical properties change gradually as their length increases, we investigated the changes of olfactory threshold and trigeminal pungency threshold with the increase of carbon chain length. MATERIALS AND METHOD: Olfactory and trigeminal pungency thresholds were measured in ethanol (C2), 1-butanol (C4), 1-hexanol (C6) and 1-octanol (C8) in 40 normal adults using a two-alternative forced-choice modified by the ascending method of limit (CCCRC) test. Plastic bottles with 30 ml of four n-aliphatic alcohols were diluted threefold successively by mineral oil. Plastic bottles containing only mineral oil were used as controls. RESULTS: The olfactory and trigeminal pungency thresholds decreased and the ratio of olfactory threshold/trigeminal pungency threshold increased with the length of carbon chain in n-aliphatic alcohols. The correlation coefficients among olfactory thresholds in each alcohol were higher than those among trigeminal pungency thresholds. CONCLUSION: Alcohol with long carbon chains showed low olfactory and trigeminal pungency thresholds, indicating that high lipid solubility is an important factor in olfaction and trigeminal chemosensitivity.
1-Butanol ; 1-Octanol ; Adult* ; Alcohols* ; Carbon* ; Ethanol ; Humans ; Mineral Oil ; Plastics ; Smell ; Solubility

Bicyclol with benzyl alcohol structure, is a poorly water-soluble drug, used for the treatment of chronic hepatitis B. To increase the drug solubility and oral bioavailability, a Bicyclol-phospholipid complex was studied on its preparation, formation mechanism, and the influence on drug physicochemical properties and oral absorption. The complex was prepared by a solvent evaporation method. The optimal formulation was selected by orthogonal experimental design, and a reasonable evaluating method of the complexation rate was established. Various methods, such as differential scanning calorimetry (DSC), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and 31P nuclear magnetic resonance (31P-NMR), were used to explore the phase state and formation mechanism of the complex. The solubility of drug in complex was investigated in water/n-octanol. Preliminary study of its absorption and liver tissue distribution in rats was also carried out. The results showed that Bicyclol and phosphatidylcholine can be complexed entirely in the molar ratio 1 : 2. Bicyclol was dispersed in phospholipids as amorphous state. They were combined by intermolecular hydrogen bond due to charge transfer effect which occurred between the two polarities of the double bond between phosphorus and oxygen (P=O) of phosphatidylcholine and benzalcohol group of Bicyclol. The solubility of the complex compared to the active pharmaceutical ingredient (API) was effectively enhanced 5.75 times in water and 7.72 times in n-octanol, separately. In addition, drug concentrations were also enhanced 43 times in plasma and 13 times in liver with one hour after administering the complex to rats via oral gavage. All of these indicated that Bicyclol with benzalcohol group can interact with phospholipids to form complex, improving drug's physicochemical properties, thus further increasing its absorption and target tissue distribution. This study also provided theoretical reference for the research of other benzalcohol derivatives complexed with phospholipids.
1-Octanol ; Animals ; Biological Availability ; Biphenyl Compounds ; pharmacokinetics ; Calorimetry, Differential Scanning ; Chemistry, Pharmaceutical ; Phospholipids ; pharmacokinetics ; Rats ; Solubility ; Spectroscopy, Fourier Transform Infrared ; Tissue Distribution ; X-Ray Diffraction