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Abstract : Solubilization of Hydroxypropyl-β-Cyclodextrin on Cholesterol in Aqueous Solution
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Abstract: Hydroxypropyl-β-Cyclodextrin (HP-β-CD), prepared via reaction of β-Cyclodextrin (β-CD) and propylene oxide (PO), is utilized to research solubilization of HP-β-CD on cholesterol in aqueous solution. HP-β-CD is characterized by Fourier Transform Infrared Spectrometry (FT-IR), and concentrations of cholesterol solution are measured by ultraviolet and visible (UV VIS) spectrophotometer. The research on optimal synthesis conditions of HP-β-CD indicates that sodium hydroxide amounts have the most effect on yields of product. The maximum solubilization multiples of HP-β-CD reaches 15, below which molecular rate of HP-β-CD and cholesterol in inclusion complex is 1:1. Keywords: Hydroxypropyl-β-Cyclodextrin, Cholesterol, Solubilization, Optimal condition, Inclusion.Download Full Article |
Abstract : Thermally Stable Multilamellar Structure of DNA/Cationic Lipid Complex in the Bulk State
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Abstract: The effect of temperature on the two types of multilamellar structures, LI and LII, formed by the complexes of DNA with a cationic lipid, cholesteryl 3β-N-(dimethylamionethyl) carbamate (DC-Chol), in the bulk state has been investigated by small angle X-ray scattering (SAXS). LI phase composing of A-DNA intercalated between the lipid bilayers with tilted tails was formed at lower lipid-to-base pair molar ratio (x < 2), while LII phase consisting of B-DNA bound to untilted lipid was formed at x > 2. In addition to the differences in lipid packing state and DNA conformation, these two lamellar phases also displayed different thermal stability. LI phase was highly thermally stable as its interlamellar distance remained essentially unperturbed even after the denaturation of A-DNA in the complex at elevated temperature. By contrast, the interlamellar distance of LII phase decreased with increasing temperature due to the release of bound water and B-DNA denaturation. Keywords: DNA-lipid complex, Lipid, DNA condensation, DC-Chol, SAXS.Download Full Article |
Abstract : Refractive Properties of Binary Mixtures Formed by an Isomer of Chlorobutane and Butyl Ethyl Ether
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Abstract: Refractive indices of the binary mixtures containing an isomer of chlorobutane (1-chlorobutane, 2-chlorobutane, 2-methyl-1-chloropropane, or 2-methyl-2-chloropropane) and butyl ethyl ether have been measured at seven temperatures from T = 283.15 to 313.15 K From these data refractive index deviations were calculated and correlated with a Redlich-Kister polynomial expansion. The refractive index deviations were found positive. Finally, from these refractive indices both densities and surface tensions of the studied systems were predicted and compared with previously reported values. Keywords: Butyl ethyl ether, Isomeric chlorobutane, Predicted properties, Refractive index.Download Full Article |
Abstract : Preferential Solvation of Acetaminophen in Propylene Glycol + Water Co-Solvent Mixtures
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Abstract: The preferential solvation parameters defined as the differences between the local mole fraction of solvents around analgesic drug acetaminophen and those for the bulk co-solvent composition in propylene glycol + water mixtures were derived from their thermodynamic properties by means of the inverse Kirkwood-Buff integrals (IKBI) and the quasi-lattice-quasi-chemical (QLQC) methods. It is found that acetaminophen is sensitive to solvation effects, so according to IKBI method the preferential solvation parameter δxPG,A, is negative in water-rich mixtures but positive in medium compositions and in co-solvent-rich mixtures. It is conjecturable that in water-rich mixtures the hydrophobic hydration around the aromatic ring and methyl group present in the drug plays a relevant role in the solvation. The bigger drug solvation by co-solvent in mixtures of similar solvent proportions and in propylene glycol-rich mixtures could be due mainly to polarity effects. Otherwise, according to QLQC method, this drug is preferentially solvated by the co-solvent in all the mixtures. Keywords: Acetaminophen, propylene glycol, solubility, inverse Kirkwood-Buff integrals, preferential solvation.Download Full Article |
