Calculation of skin permeability coefficient for ionized and unionized species of indomethacin.

The contribution of ionized and unionized species to the overall permeation of weak electrolytes through the skin was investigated to determine the effect of pH in the vehicle on the permeability of indomethacin (IDM), as a model drug, through hairless rat skin. The permeability of IDM through polydimethylsiloxane (silicone) and poly(2-hydroxyethyl methacrylate) (pHEMA) membranes which may reflect lipid and aqueous pathway, respectively, was also measured for comparison. As the pH in the vehicle increased, there was an exponential increase in the skin permeation rate of IDM. The permeation rate of IDM through the silicone membrane was constant independent of pH, whereas that through the pHEMA membrane increased with increasing pH, similar to the skin permeation. The permeability coefficients of ionized and unionized species through the skin estimated using the skin permeation rates and solubilities of IDM at various pHs were 1.50 x 10(-7) and 2.79 x 10(-5) cm/s, respectively. These results indicated that the permeation of ionized species greatly contributed to the total permeation of IDM at higher pH, and that the total permeation rate of IDM was determined by the permeation of unionized species at lower pH. These contributions depend on the pH and pKa values and the ratio of permeability coefficient of each species. It was also confirmed that the skin has at least two kinds of permeation pathways and these two species permeate through a different pathway.     

Photoreduction de la benzophenone par des phtalimidines et des dihydro isoquinolones: Etude chimique par RMN PNIC

Benzophenone is photoreduced by pthalimidines and dihydro isoquinolones. The hydrogen atom α to the nitrogen atom is abstracted and radical coupling leads to adducts. CIDNP studies of these adducts show inversion of polarisation for the adduct on the N-alkyl chain when the nitrogen is bound to a benzylic methylene. This inversion is explained by considering that the radical on the N-alkyl chain derives from the radical on the ring.     

Synthesis and Physicochemical Study of Solid Complexes of Ti(IV), Zr(IV), and Zn(II) with Chrysin

Previously unknown solid complexes of Ti(IV), Zr(IV), and Zn(II) with chrysin were isolated, identified, and studied by thermogravimetric analysis and by UV-Vis, IR, and NMR spectroscopy.     

Thermodynamic excess quantities in the adsorption of sodium alkylsulfonates at the air-solution interface

Colloid and Polymer Science - Data on the surface tension of sodium alkylsulfonate solutions at different temperatures and surfactant concentrations are presented. By applying the thermodynamic...     

Mass spectral study on thiazolo[3,2-a]benzimidazoles. Studies on heterocyclic compounds. IV

Condensation of α-halocarbonyl compounds and 2-mercaptobenzimidazole gives thiazolo-[3,2-a]benzimidazoles. This condensation occurred at the mercapto group of the benzimidazole followed by cyclization to form the thiazole ring. This was confirmed by the examination of the mass spectra of 2- and 3-methylthiazolo[3,2-a]benzimidazoles, 2- and 3-phenylthiazolo[3,2-a]-benzimidazoles, and their derivatives.     

Die Kristallstruktur des l, 6-8, 13-Bis-oxido-[14]-annulens

Crystals of 1,6-8, 13-bis-oxido-[14]-annulene are monoclinic, a = 9,29, b = 9,74, c = 11,46 Å, β = 90,0°, space group P 2₁/c, with 4 molecules in the unit cell. The structure has been solved by direct methods and refined by full-matrix least-squares analysis of three-dimensional intensity data. The cis-configuration of the two oxygen bridges is confirmed, and the observed molecular parameters are in full accord with the aromatic properties of the molecule.     

The role of metallic palladium in the reductive decomposition of π-allyl palladium chloride in aqueous alkaline solutions

Russian Chemical Bulletin -     

Divinyl Sulfoxide: XI. Selective Addition of Carbonodithioate Anions to Divinyl Sulfoxide in the Water-Benzene System

Selective monoaddition of carbonodithioate anions to divinyl sulfoxide gives rise to O-alkyl S-[2-(vinylsulfinyl)ethyl] carbonodithioates [ROC(S)SK, R = Et, Bu; 42–50°C, 6 h, NaHCO₃, aqueous benzene].