Search results for "hydrophobic"
showing 10 items of 332 documents
Penetration enhancer containing vesicles as carriers for dermal delivery of tretinoin.
2011
The ability of a recently developed novel class of liposomes to promote dermal delivery of tretinoin (TRA) was evaluated. New penetration enhancer-containing vesicles (PEVs) were prepared adding to conventional phosphatidylcholine vesicles (control liposomes) different hydrophilic penetration enhancers: Oramix® NS10 (OrNS10), Labrasol® (Lab), Transcutol® P (Trc), and propylene glycol (PG). Vesicles were characterized by morphology, size distribution, zeta potential, incorporation efficiency, stability, rheological behaviour, and deformability. Small, negatively charged, non-deformable, multilamellar vesicles were obtained. Rheological studies showed that PEVs had fluidity higher than conven…
Making Broad Proteome Protein Measurements in 1−5 min Using High-Speed RPLC Separations and High-Accuracy Mass Measurements
2005
The throughput of proteomics measurements that provide broad protein coverage is limited by the quality and speed of both the separations as well as the subsequent mass spectrometric analysis; at present, analysis times can range anywhere from hours (high throughput) to days or longer (low throughput). We have explored the basis for proteomics analyses conducted on the order of minutes using high-speed capillary RPLC combined through on-line electrospray ionization interface with high-accuracy mass spectrometry (MS) measurements. Short 0.8-microm porous C18 particle-packed 50-microm-i.d. capillaries were used to speed the RPLC separations while still providing high-quality separations. Both…
Ferrocene-functionalized anilines as potent anticancer and antidiabetic agents: Synthesis, spectroscopic elucidation, and DFT calculations
2022
Abstract Ferrocene derivatives have attracted significant interest as potent biological agents and novel drug candidates. Hence, the present research work was focused on the synthesis and characterization of ferrocene-integrated anilines (FB1-FB4) through different spectroscopic techniques such as: FT-IR, multinuclear (1H and 13C) NMR, Raman, atomic absorption spectroscopy, elemental analysis, and single-crystal X-ray crystallography. The crystallographic analysis revealed a supramolecular structure mediated by secondary non-covalent interactions (π—H and π—π). These ferrocenyl derivatives demonstrated a quasi-reversible electrochemical behavior with one electron transfer from Fe(II) to Fe(…
Sample streaks and smears in immobilized pH gradient gels
1996
In immobilized pH gradient (IPG) gel formulations as wide as pH 4-9, encompassing neutrality and containing the pK 7.0 acrylamido buffer as one of the buffering ions, smears are directly proportional to the total amount of the pK 7.0 species. At a total level of 10 mM pK 7.0 in these gel formulations, severe smears occur not only for mildly hydrophobic proteins (e.g., recombinant alcalase and termamylase) but also for the relatively hydrophilic pI marker proteins. Streaks and smears are essentially abolished in recipes devoid of the pK 7.0 compound or in formulations containing a maximum of 3 mM of this component. Although partitioning in water/n-octanol has shown the pK 7.0 acrylamido buff…
Retention mechanisms in micellar liquid chromatography.
2008
Micellar liquid chromatography (MLC) is a reversed-phase liquid chromatographic (RPLC) mode with mobile phases containing a surfactant (ionic or non-ionic) above its critical micellar concentration (CMC). In these conditions, the stationary phase is modified with an approximately constant amount of surfactant monomers, and the solubilising capability of the mobile phase is altered by the presence of micelles, giving rise to diverse interactions (hydrophobic, ionic and steric) with major implications in retention and selectivity. From its beginnings in 1980, the technique has evolved up to becoming a real alternative in some instances (and a complement in others) to classical RPLC with hydro…
The solubilization site of 5,10,15,20-tetrakis-(2,6-dichlorophenyl)-porphyrin-Mn(III) in DPPC vesicles: A spectrophotometric and tensiometric study
2006
Abstract The solubilization site of 5,10,15,20-tetrakis-(2,6-dichlorophenyl)-porphyrin-Mn(III) (MnTDPPC) in l -α-dipalmitoylphosphatidyl choline (DPPC) vesicles was determined in a systematic UV–vis spectrophotometric study. Measurements of the MnTDPPC absorbance have been conducted at constant temperatures (in the interval 30 °C ≤ T ≤ 48 °C) and varying concentrations of phospholipid. In the entire temperature range, the absorption due to MnTDCCP was found to increase with increasing DPPC concentration, until it reaches a plateau value. The data have been analyzed using a pseudo-phase model yielding the binding constant of MnTDCPP to vesicular aggregates. No significant temperature depende…
A Study of Lipid-Lipid and Lipid-Polypeptide Interactions by High Performance Liquid Chromatography
1984
Abstract Ternary systems containing phosphatidylcholine-cholesterol, phosphatidylcholine-gramicidin A or cholesterol-gramicidin A in tetrahydrofuran have been examined by high performance liquid chromatography. Preferential solvation of cholesterol and especially gramicidin A by phosphatidylcholine is observed. These results are interpreted in terms of hydrophobic interactions between membrane components.
Effect of ethanol on yeast film formation
1999
<p style="text-align: justify;">In this study, we have investigated the influence of ethanol on yeast film formation and cell surface hydrophobicity (CSH). A yeast strain (P3) previously isolated from film yeast was grown in a medium containing increasing ethanol concentration ranging from 0 to 14 p. cent (v/v). It results from this study that up to 10 p. cent ethanol, the greater was the ethanol concentration, the greater was the growth of film. Using two different techniques (phase partition method, magnobead assay), we have shown that ethanol altered the CSH of the yeast. The measured hydrophobicity (p. cent) of cells grown without ethanol was 65 p. cent compared with 81 p. cent wi…
Packings and stationary phases for biopolymer separations by HPLC
1987
Packings and stationary phases applied to high resolution separations of proteins, enzymes, and nucleic acids must satisfy a series of distinct criteria that are different from those usually required by HPLC of low molecular weight non-biologically active analytes. These requirements have been met through substantial improvements in classical gel media together with novel developments in silica supports, and have led to a family of products with tailor-made and reproducible properties. Supports consisting of cross-linked organic gels, and inorganic materials (mostly silicas) are now available with graduated particle sizes, pore sizes, porosities and surface areas as well as non-porous beads…
Quantitation of hydrophobicity in micellar liquid chromatography
1999
Abstract Micellar liquid chromatography (MLC) is shown to be a promising technique for measuring the hydrophobicity of solutes. The presence of micelles has a profound effect on the chromatographic characteristics of reversed-phase columns. The linear relationships between the logarithm, log k , of the retention factor and such diverse properties as the number of carbon atoms in homologous series, octanol–water partition coefficients and solvatochromic parameters, which are observed in conventional reversed-phase liquid chromatography (RPLC), are not usually valid in MLC. For series of compounds exhibiting a wide range of hydrophobicity, k itself is linearly related to these properties. The…