Tsuguchika Yoshida

Intratracheal delivery of insulin : absorption from solution and aerosol by rat lung

Abstract In this study, we investigated the dynamics of insulin absorption from the lung with reference to bioavailability. Human insulin in 10 μl of aqueous solution and an insulin aerosol were administered into the exposed trachea of anesthetized rats. Blood samples were collected from the jugular vein at specified intervals and the plasma concentration of insulin was determined by an EIA. The relative bioavailability of insulin after intratracheal administration in 10 μl of pH 7.0 isotonic phosphate buffer and pH 3.0 isotonic citrate buffer was 13 and 42%, respectively, of that obtained after subcutaneous administration. Although insulin absorption in the presence of surfactants such as glycocholate, surfactin, and Span 85 was 3–4-times greater than that without surfactants, the co-administration of EDTA and salicytate, which previously enhanced the absorption of rectally administered insulin, did not increase the intratracheal absorption of insulin. The concomitant administration of nafamostat, a protease inhibitor, produced modest effects. The relative bioavailability of insulin given as an intratracheal aerosol was similar to that after subcutaneous administration. These observations indicate that the intratracheal route may be useful for the delivery of insulin.

New preparation method for 9-anthryldiazomethane (ADAM) as a fluorescent labeling reagent for fatty acids and derivatives

A preparation method for 9-anthryldiazomethane (ADAM) as a fluorescent labeling reagent for carboxylic acids is described. 9-Anthraldehyde hydrazone is oxidized with an organic oxidant, N-chlorosuccinimide, in an organic solvent such as ethyl acetate to give ADAM, and then the reaction mixture is directly used as the reagent solution for the derivatization of carboxylic acids. Both the oxidation and the derivatization reaction are carried out at room temperature, and an aliquot of the derivatization mixture is directly injected into a chromatograph. 9-Anthrylmethyl ester derivatives formed from ADAM and various carboxylic acids are sufficiently separated on a reversed-phase column and are sensitively detected fluorometrically. The present method was applied to the high-performance liquid chromatographic determination of long and short chain fatty acids, keto acids, and hydroxy acids.

Reactivity of Taurine with Aldehydes and Its Physiological Role.

The chemical reactions of the amino group of taurine with aldehydes were investigated. Glucose, acetaldehyde, and malondialdehyde were used as aldehydes. After taurine had reacted, the amounts of remaining taurine and aldehydes were measured, and the reactivity was evaluated. Amino acids such as glycine, alpha-alanine, and beta-alanine were compared because of their structural resemblance to each other. Taurine showed a high reactivity with each one of the aldehydes tested. It is known that protein is altered through reactions of the amino group with various aldehydes. Low density lipoprotein (LDL) was used as a model protein and the inhibiting effect of taurine against the modification of LDL by malondialdehyde was examined. It was shown that the inhibiting effects of taurine correlated with the reactivity of malondialdehyde with amino acids. Further, the taurine-glucose reaction product showed an antioxidative effect on the peroxidation of liposomes made of yolk phosphatidylcholine as a biomembrane model. The results suggest the possibility of an inhibiting effect of taurine against the modification of protein, as well as an antioxidative effect through the reactions of taurine with aldehydes in vivo.

Three flavonol glycosides from Epimedium koreanum

Abstract Three new flavonol glycosides: 4′-methoxy-5-hydroxy-8-3,3-dimethylallylflavone 3-glycosyl(1→2)rhamnoside-7-glucoside, 3-xylosyl(1→2)rhamnoside-7-glucoside and 3-rhamnosyl(1→2)rhamnoside-7-glucoside and icariin were characterized from the aerial parts of Epimedium koreanum .

Reactivity of taurine with aldehydes and its physiological role.

The chemical reactions of the amino group of taurine with aldehydes were investigated. Glucose, acetaldehyde, and malondialdehyde were used as aldehydes. After taurine had reacted, the amounts of remaining taurine and aldehydes were measured, and the reactivity was evaluated. Amino acids such as glycine, alpha-alanine, and beta-alanine were compared because of their structural resemblance to each other. Taurine showed a high reactivity with each one of the aldehydes tested. It is known that protein is altered through reactions of the amino group with various aldehydes. Low density lipoprotein (LDL) was used as a model protein and the inhibiting effect of taurine against the modification of LDL by malondialdehyde was examined. It was shown that the inhibiting effects of taurine correlated with the reactivity of malondialdehyde with amino acids. Further, the taurine-glucose reaction product showed an antioxidative effect on the peroxidation of liposomes made of yolk phosphatidylcholine as a biomembrane model. The results suggest the possibility of an inhibiting effect of taurine against the modification of protein, as well as an antioxidative effect through the reactions of taurine with aldehydes in vivo.

Rapid and simple determination of sennoside A and B in rhei rhizoma by ion-pair high-performance liquid chromatography.

A simple and precise ion-pair high-performance liquid chromatographic method was developed for the determination of sennoside A and B in Rhei Rhizoma. A reversed-phase chromatographic system consisting of a chemically bonded ODS silica gel column with an acetate buffer (pH 5.0)-acetonitrile (68:32), containing 5 mM tetra-n-heptylammonium bromide, as the mobile phase was used. Sennoside A and B in this crude drug were separated and determined within 20 min after direct injection of the solution extracted with 70% methanol. The results for various samples are presented.

Determination of carnitine by high-performance liquid chromatography using 9-anthryldiazomethane

The high-performance liquid chromatographic determination of carnitine chloride was investigated by using 9-anthryldiazomethane (ADAM) as a pre-column derivatization reagent. Carnitine chloride and the internal standard N,N-dimethylglycine reacted with ADAM to give a stable ester derivative in the presence of sodium dodecyl sulphate (SDS) used to mask the basic function. The ADAM derivative of carnitine was separated from decomposition products of the reagent and related compounds such as amino acid derivatives on a silica gel column eluted with methanol-5% aqueous SDS-phosphoric acid (990:10:1). The calibration plot was linear over a sample concentration range from 0.02 to 100 ng per injection. The detection limit for carnitine chloride was about 1 pg per injection (signal to noise ratio = 4), by fluorometric detection.