Simple determination of o-phenylphenol in skin lotion by high-performance liquid chromatography coupled with fluorescence detection after pre-column derivatization with 4-(N-chloroformylmethyl-N-methylamino)-7-nitro-2,1,3-benzoxadiazole.

o-Phenylphenol (OPP) in skin lotion was quantitated by high-performance liquid chromatography coupled with fluorescence detection after pre-column derivatization with 4-(N-chloroformylmethyl-N-methylamino)-7-nitro-2,1,3-benzoxadiazole (NBD-COCl) in borate buffer (pH 8.5) at room temperature for 2 min. The column [150 mm x 3.

Effects of eugenol-reduced clove extract on glycogen phosphorylase b and the development of diabetes in db/db mice.

We found that the 50% aqueous EtOH extract of clove (Syzygium aromaticum) had potent dose-dependent inhibitory activity toward glycogen phosphorylase b and glucagon-stimulated glucose production in primary rat hepatocytes. Among the components, eugeniin inhibited glycogen phosphorylase b and glucagon-stimulated glucose production in primary rat hepatocytes, with IC50 values of 0.14 and 4.

Determination of hinokitiol in skin lotion by high-performance liquid chromatography-ultraviolet detection after precolumn derivatization with 4-fluoro-7-nitro-2,1,3-benzoxadiazole.

Hinokitiol, a potent, broad-spectrum antibacterial agent, is a component of various personal care products. In this study, the concentration of hinokitiol in skin lotion was analyzed by means of high-performance liquid chromatography-ultraviolet detection (380 nm) after precolumn derivatization with 4-fluoro-7-nitro-2,1, 3-benzoxadiazole (NBD-F). A standard curve was obtained after derivatization of the authentic compound with NBD-F in borate buffer (pH 9.

Determination of kojic acid in a skin-whitening cosmetic by high-performance liquid chromatography coupled with ultraviolet detection after pre-column derivatization with 4-fluoro-7-nitro-2,1,3-benzoxadiazole.

Various methods for the determination of kojic acid (KA), a skin-whitening agent, have been reported by high-performance liquid chromatography (HPLC). In this study, the concentration of KA in a skin-whitening cosmetic was analyzed by HPLC with ultraviolet detection (380 nm) after pre-column derivatization with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F) in order to improve the sensitivity. The HPLC column was 150 mm x 3.

High-performance liquid chromatography with dual-wavelength ultraviolet detection for measurement of hinokitiol in personal care products.

Hinokitiol is found in the heartwood of several cupressaceous plants and is frequently added to cosmetic products such as hair restorers, skin lotions, and body soaps because of its potent and broad-spectrum antibacterial activity. In this study, we established a simple method of hinokitiol determination by high-performance liquid chromatography (HPLC) with dual-wavelength ultraviolet detection at 240 and 345 nm, using a reversed-phase C4 column (RP-4). The retention time of hinokitiol was 7.

Sensitive determination of 4-(4-bromophenyl)-4-hydroxypiperidine, a metabolite of bromperidol, in rat plasma by HPLC with fluorescence detection after pre-column derivatization using 4-fluoro-7-nitro-2,1,3-benzoxadiazole.

The purpose of this study was to determine the level of 4-(4-bromophenyl)-4-hydroxypiperidine (BPHP), a bromperidol (BRO) metabolite, in rat plasma by HPLC with fluorescence detection after pre-column derivatization using 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F). After basic extraction of the samples with benzene, derivatization with NBD-F was conducted in borate buffer (pH 8.0) at 60 degrees C for 3 min.

Effect of imatinib mesilate on the disposition kinetics of ciclosporin in rats.

The purpose of this study was to investigate the effect of imatinib mesilate on the disposition kinetics of ciclosporin in rats. The blood concentration-time course and pharmacokinetic parameters of ciclosporin did not significantly change after intravenous injection of ciclosporin (10 mg kg(-1)) in rats treated with imatinib mesilate (50 mg kg(-1)) as compared with a control. When ciclosporin (10 mg kg(-1)) was orally administered, the time course, area under the curve, bioavailability and peak blood concentration of ciclosporin were significantly increased in rats that had been treated with imatinib mesilate 2 h before ciclosporin administration as compared with the control.

Sensitive determination of 4-(4-chlorophenyl)-4-hydroxypiperidine, a metabolite of haloperidol, in a rat biological sample by HPLC with fluorescence detection after pre-column derivatization using 4-fluoro-7-nitro-2,1,3-benzoxadiazole.

4-(4-Chlorophenyl)-4-hydroxypiperidine (CPHP), one of the metabolites of haloperidol, is considered to exhibit brain toxicity. CPHP concentrations in plasma and tissue homogenates (each 200 microL) from rats were analyzed by HPLC fluorescence detection after pre-column derivatization with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F). After basic extraction of the samples with benzene, the derivatization with NBD-F was conducted in borate buffer (pH 8.

Simultaneous liquid chromatographic assay of amantadine and its four related compounds in phosphate-buffered saline using 4-fluoro-7-nitro-2,1,3-benzoxadiazole as a fluorescent derivatization reagent.

Simultaneous HPLC assay of 1-adamantanamine hydrochloride (amantadine) and its four related compounds [2-adamantanamine hydrochloride (2-ADA), 1-adamantanmethylamine (ADAMA), 1-(1-adamantyl)ethylamine hydrochloride (rimantadine) and 3,5-dimethyl-1-adamantanamine hydrochloride (memantine)] in phosphate-buffered saline (pH 7.4) after pre-column derivatization with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F) was developed. Phosphate-buffered saline samples were mixed with borate buffer and NBD-F solution in acetonitrile at 60 degrees C for 5 min and injected into HPLC.

Simultaneous analysis of haloperidol, its three metabolites and two other butyrophenone-type neuroleptics by high performance liquid chromatography with dual ultraviolet detection.

We investigated simultaneous determination of haloperidol (HAL), its three metabolites [reduced HAL (R-HAL), 3-(4-fluorobenzoyl)propionic acid (FBPA) and 4-(4-chlorophenyl)-4-hydroxypiperidine (CPHP)] and two related compounds [spiperone (SPI) and droperidol (DRO)] in phosphate-buffered saline using high-performance liquid chromatography (HPLC) coupled with dual ultraviolet detection (220 and 250 nm). Retention times of HAL, R-HAL, FBPA, CPHP, SPI and DRO were 16.8, 11.

Simultaneous determination of the binding of amantadine and its analogues to synthetic melanin by liquid chromatography after precolumn derivatization with dansyl chloride.

For the determination of amantadine (1-ADA), 2-adamantanamine (2-ADA), memantine (MEM), and rimantadine (RIM) in melanin binding studies, the simultaneous determination of 1-ADA or 2-ADA, MEM, and RIM is investigated by high-performance liquid chromatographic assay with dansyl chloride as a fluorescent derivative reagent. Dansyl derivatives with fluorescent intensity are detected at an excitation wavelength of 370 nm and an emission wavelength of 506 nm. Retention times of 1-ADA, 2-ADA, MEM, and RIM derivatives are 12.

Pharmacokinetic interaction with digoxin and glucocorticoids in rats detected by radio-immunoassay using a novel specific antiserum.

We previously prepared a more specific antiserum (Antiserum-I) to digoxin (Dx) compared with commercially available anti-Dx antiserum (Antiserum-II), clinically used in the therapeutic drug monitoring of Dx. The aims of this study are to compare Dx disposition kinetics by radio-immunoassay (RIA) using Antiserum-I and Antiserum-II, and evaluate the drug-drug interaction with Dx and glucocorticoids in rats. When Dx metabolites were added to rat serum containing Dx, the recovery ratios using Antiserum-I showed 100 to 110% and were remarkably lower than those using Antiserum-II.

Simultaneous determination of amantadine and rimantadine by HPLC in rat plasma with pre-column derivatization and fluorescence detection for pharmacokinetic studies.

We investigated simultaneous high-performance liquid chromatographic (HPLC) determination of amantadine hydrochloride (AMA) and rimantadine hydrochloride (RIM) levels in rat plasma after fluorescent derivatization with o-phthalaldehyde and 2-mercaptoethanol. Afterwards, the method was applied to determine their pharmacokinetics. The retention times of AMA and RIM derivatives were 12.

Liquid chromatographic determination of 1-adamantanamine and 2-adamantanamine in human plasma after pre-column derivatization with o-phthalaldehyde and 1-thio-beta-D-glucose.

We investigated high-performance liquid chromatographic (HPLC) determination of 1-adamantanamine hydrochloride (1-ADA) and 2-adamantanamine hydrochloride (2-ADA) in human plasma after the derivatization with o-phthalaldehyde (OPA) and 1-thio-beta-D-glucose (TG). Extracted human plasma samples were mixed with OPA and TG at room temperature for 6 min and injected onto HPLC. Retention times of 1-ADA and 2-ADA derivatives were 12.

Measurement of beta-methyldigoxin level in serum from patients by enzyme immunoassay using novel specific antiserum with a phenyl boric acid column.

The authors compared serum beta-methyldigoxin (MDx) levels in digitalized patients by enzyme immunoassay (EIA) using anti-MDx 3'-hemisuccinate BSA antiserum (antiserum-I) with commercial antidigoxin antiserum (antiserum-II). The usefulness of a phenyl boric acid (PBA) column for pretreatment of the serum samples was also investigated. The assay using antiserum-I demonstrated good accuracy and precision in the concentration range of 0.

Pharmacokinetic study of beta-methyldigoxin by enzyme immunoassay using a novel specific antiserum in rats.

We previously showed that enzyme immunoassay (EIA) of beta-methyldigoxin (MDx3) using anti-MDx3 3'-hemisuccinate-bovine serum albumin antiserum (Antiserum-I) was superior to that using commercial anti-digoxin antiserum (Antiserum-II) in terms of specificity and that pretreatment of human serum with phenyl boric acid (PBA) column was effective. In the present study, we examined the precision of EIA using Antiserum-I and the recovery of MDx3 after PBA column treatment in rat serum, and also investigated pharmacokinetic changes of MDx3 in rats. The intra- and inter-assay variations and recovery tests using Antiserum-I were good.

Establishment of enzyme immunoassay for measuring beta-methyldigoxin levels in human serum by specific antiserum.

We investigated the specificity of obtained antisera to beta-methyldigoxin by the enzyme immunoassay. Three types of hapten-bovine serum albumin (BSA) conjugates were synthesized to obtain high specific antisera to beta-methyldigoxin. The haptens were linked to the carrier protein through hemisuccinate at C-3' and C-3'' positions in the digitoxose chain and at C-12 position in the aglycone.

Modulation of mdr1a and CYP3A gene expression in the intestine and liver as possible cause of changes in the cyclosporin A disposition kinetics by dexamethasone.

We investigated the effect of dexamethasone (DEX) on the disposition kinetics of cyclosporin A (CyA) and the mechanism of this drug interaction. Rats were treated with DEX (1 or 75mg/kg per day, i.p.