A simple and sensitive spectrophotometric method has been developed for the determination of cetirizine (I), ebastine (II),fexofenadine (III), ketotifen (IV), and loratadine (V) based on ion-pair complex formation with erythrosine B. The pink color of the produced complex was measured at 550 nm without solvent extraction. Appropriate conditions were established by studying the color reaction between erythrosine B and the studied drugs to obtain the maximum sensitivity. Beer-Lambert’s law is obeyed in the concentration ranges 1–7, 1–8, and 1–6

A simple and sensitive spectrophotometric method has been developed for the determination of cetirizine (I), ebastine (II),fexofenadine (III), ketotifen (IV), and loratadine (V) based on ion-pair complex formation with erythrosine B. The pink color of the produced complex was measured at 550 nm without solvent extraction. Appropriate conditions were established by studying the color reaction between erythrosine B and the studied drugs to obtain the maximum sensitivity. Beer-Lambert’s law is obeyed in the concentration ranges 1–7, 1–8, and 1–6

A simple and sensitive spectrophotometric method has been developed for the determination of cetirizine (I), ebastine (II),fexofenadine (III), ketotifen (IV), and loratadine (V) based on ion-pair complex formation with erythrosine B. The pink color of the produced complex was measured at 550 nm without solvent extraction. Appropriate conditions were established by studying the color reaction between erythrosine B and the studied drugs to obtain the maximum sensitivity. Beer-Lambert’s law is obeyed in the concentration ranges 1–7, 1–8, and 1–6

A novel, highly sensitive and selective fluorimetric liquid chromatographic method for simultaneous determination of medium chain aliphatic aldehydes was developed. The method was based on the derivatization of aliphatic aldehydes with 1,2-di(2-furyl)-1,2-ethanedione (2,2'-furil), a novel fluorogenic reagent, to form highly fluorescent difurylimidazole derivatives. The fluorescence derivatives were separated in less than 20 min on a reversed-phase ODS column using an isocratic elution with a mixture of methanol-water (80:20, v/v%). The detection limits were from 0.19 to 0.50 nM (1-10 fmol/injection) at a signal-to-noise ratio (S/N) of 3. This method was successfully applied for monitoring of aliphatic aldehydes in healthy human sera by a simple pretreatment procedure without interferences from serum constituents.

A novel, highly sensitive and selective fluorimetric liquid chromatographic method for simultaneous determination of medium chain aliphatic aldehydes was developed. The method was based on the derivatization of aliphatic aldehydes with 1,2-di(2-furyl)-1,2-ethanedione (2,2'-furil), a novel fluorogenic reagent, to form highly fluorescent difurylimidazole derivatives. The fluorescence derivatives were separated in less than 20 min on a reversed-phase ODS column using an isocratic elution with a mixture of methanol-water (80:20, v/v%). The detection limits were from 0.19 to 0.50 nM (1-10 fmol/injection) at a signal-to-noise ratio (S/N) of 3. This method was successfully applied for monitoring of aliphatic aldehydes in healthy human sera by a simple pretreatment procedure without interferences from serum constituents.

A novel, highly sensitive and selective fluorimetric liquid chromatographic method for simultaneous determination of medium chain aliphatic aldehydes was developed. The method was based on the derivatization of aliphatic aldehydes with 1,2-di(2-furyl)-1,2-ethanedione (2,2'-furil), a novel fluorogenic reagent, to form highly fluorescent difurylimidazole derivatives. The fluorescence derivatives were separated in less than 20 min on a reversed-phase ODS column using an isocratic elution with a mixture of methanol-water (80:20, v/v%). The detection limits were from 0.19 to 0.50 nM (1-10 fmol/injection) at a signal-to-noise ratio (S/N) of 3. This method was successfully applied for monitoring of aliphatic aldehydes in healthy human sera by a simple pretreatment procedure without interferences from serum constituents.

A novel, highly sensitive and selective fluorimetric liquid chromatographic method for simultaneous determination of medium chain aliphatic aldehydes was developed. The method was based on the derivatization of aliphatic aldehydes with 1,2-di(2-furyl)-1,2-ethanedione (2,2'-furil), a novel fluorogenic reagent, to form highly fluorescent difurylimidazole derivatives. The fluorescence derivatives were separated in less than 20 min on a reversed-phase ODS column using an isocratic elution with a mixture of methanol-water (80:20, v/v%). The detection limits were from 0.19 to 0.50 nM (1-10 fmol/injection) at a signal-to-noise ratio (S/N) of 3. This method was successfully applied for monitoring of aliphatic aldehydes in healthy human sera by a simple pretreatment procedure without interferences from serum constituents.

The binding of a lophine-based fluorescence probe, 4-[4-(4-dimethylaminophenyl)-5-phenyl-1H-imidazol-2-yl]benzoic acid methyl ester (DAPIM) with human serum albumin (HSA) was investigated by fluorescence spectroscopy under physiological conditions. While DAPIM shows extreme low fluorescence in aqueous solution, DAPIM binding with HSA emits strong fluorescence at 510 nm. The binding constant and binding number determined by Scatchard plot was 3.65×106 M-1 and 1.07, respectively. Competitive binding between DAPIM and other ligands such as warfarin, valproic acid, diazepam and oleic acid, were also studied fluorometrically. The results indicated that the primary binding site of DAPIM to HSA is site II at subdomain IIIA. DAPIM can be a useful fluorescence probe for the characterization of drug-binding sites. In addition to the interaction study, because the fluorescence intensity of DAPIM increased in proportion to HSA concentration, its potential in HSA assay for serum sample was also evaluated.

Butyl methacrylate (BMA)-ethylene dimethacrylate (EDMA)-methacrylic acid (MAA) and BMA-EDMA-2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) monolithic columns were prepared by varying the percentage of ionic monomers for capillary electrochromatography. Monolithic columns with a higher content of ionic monomers provided better column efficiency, and the performance of BMA-EDMA-MAA monoliths was better than BMA-EDMA-AMPS. To characterize and optimize BMA-EDMA-MAA monoliths, the effects of the content of cross-linker and the total monomer in the polymerization mixture on column performance were also studied. Plate heights of 8.2 mm for the unretained solute (thiourea) and 12.6 mm for the retained solute (naphthalene) were achieved with a monolithic column using 2.5% MAA (Column I).

The present study aims to investigate the possibility of interaction of donepezil (DP) and galantamine (GAL) as acetylcholinestrase inhibitors, on memantine (MT) hydrochloride in rat plasma by HPLC-fluorescence detection. The separation of MT was achieved within 12 min without interference of DP and GAL on the chromatogram. MT levels in rat plasma with a single administration of MT (2.5 mg/kg, i.p.) and those with a co-administration of DP (5.0 mg/kg, i.p.) and GAL (3 mg/kg, i.p.) were monitored. MT concentrations determined in rat plasma ranged from 10.0 to 245.6 ng/mL. Significant difference was observed in the behavior of MT with a co-administration of DP, while no significant difference was observed with a co-administration of GAL.