Derivative spectrophotometric, colorimetric and high performance liquid chromatographic methods, for the determination of the antihistaminic cetirizine dihydrochloride in tablet form were described. Spectrophotometrically, cetirizine was determined by the measurement of its first (1D) and second (2D) derivative amplitudes at 239 (peak) and 243-233 nm (peak-to-trough), respectively. The aqueous ...

Membrane voltage controls the passage of ions through voltage-gated K (K(v)) channels, and many studies have demonstrated that this is accomplished by a physical gate located at the cytoplasmic end of the pore. Critical to this determination were the findings that quaternary ammonium ions and certain peptides have access to their internal pore-blocking sites only when the channel gates are open...

Four new dipyridylamino-substituted s-triazine ligands DBB (N(2),N(2),N(4),N(4)-tetrabenzyl-N(6),N(6)-di(pyridin-2-yl)-1,3,5-triazine-2,4,6-triamine), DDB (N(2),N(2),N(4),N(4)-tetrabutyl-N(6),N(6)-di(pyridin-2-yl)-1,3,5-triazine-2,4,6-triamine), DCCl (6-chloro-N(2),N(2)-dicyclohexyl-N(4),N(4)-di(pyridin-2-yl)-1,3,5-triazine-2,4-diamine) and DDT (N(2),N(2),N(4),N(4)-tetraphenyl-N(6),N(6)-di(pyri...

Some 2-iminothiazolidin-4-ones have been synthesized by the reaction of dialkyl acetylenedicarboxylates with thiosemicarbazones. The reaction was performed in the presence of 10 mol% of triphenylphosphine and tetrabutylammonium bromide as a phase transfer catalyst in water as a green solvent. All the synthesized compounds were characterized by their physical and spectral data.

Some 2-iminothiazolidin-4-ones have been synthesized by the reaction of dialkyl acetylenedicarboxylates with thiosemicarbazones. The reaction was performed in the presence of 10 mol% of triphenylphosphine and tetrabutylammonium bromide as a phase transfer catalyst in water as a green solvent. All the synthesized compounds were characterized by their physical and spectral data.

The design and synthesis of receptors for the selective recognition and sensing of anions, through the use of weak interactions such as hydrogen bonding, is an active area of research within supramolecular chemistry. Structures based on urea and thiourea recognition sites are of particular interest due to their strong, and tuneable hydrogen binding abilities, and their relatively easy syntheses...

The selective oxidation of 2,3,6-trimethylphenol (TMP) is of great importance for the preparation of 2,3,5-trimethyl-pbenzoquinone (TMBQ), a key intermediate in the production of Vitamin E. Various oxidant/catalyst, such as O2 or H2O2/CuCl2 (especially with various co-catalysts) have been employed in this oxidation process on the industrial scale. However, the main drawback of the above-mention...

In this paper, we report the fabrication and photoelectric properties of CdTe/TiO2 nanocrystal multilayer. Negatively charged CdTe nanocrystal hydrosols were synthesized in the aqueous phase with 3-mercaptopropionic acid as a surface modifier. The characterization of transmission electron microscopy (TEM) and UV-visible absorption spectrum indicates the resultant CdTe nanocrystal hydrosols are ...

Flap endonucleases (FENs), essential for DNA replication and repair, recognize and remove RNA or DNA 50-flaps. Related to FEN specificity for substrates with free 50-ends, but controversial, is the role of the helical arch observed in varying conformations in substrate-free FEN structures. Conflicting models suggest either 50-flaps thread through the arch, which when structured can only accommo...

The metabolic disposition of the new fluoroquinolone antibacterial agent DW116 has been studied in Sprague-Dawley rats. The compound was absorbed well and demonstrated excellent oral bioavailability. The plasma kinetic profiles were characterized by monoexponential elimination with an elimination half life of 3-4 hr. The apparent mean total clearance (ClT) and the volume of distribution (Vss) r...