An efficient synthesis of polyhydroquinoline derivatives was reported via four-component coupling reactions of aldehydes, 1,3-dicarbonyl ketones (dimedone or 1,3-cyclohexanedione), ethyl acetoacetate or methyl acetoacetate and ammonium acetate in the presence of a catalytic amount of nanocrystalline TiO2 under solvent free conditions. The reported method is mild, rapid and has the advantages su...

We evaluated and compared three analytical procedures for measuring creatinine by testing pooled sera and sera from individual human subjects. In two of the methods, an enzymic and a conventional colorimetric procedure, creatinine was separated from serum proteins with tungstic acid and detected at 520 nm after reaction with alkaline picrate (Jaff#{233} reagent). The amount of enzymaticaIly act...

Verapamil is a newly marketed antiarrhythmic drug. It has a significant presystemic elimination when administered orally and, therefore, intravenous therapy is often recommended. Optimum therapeutic effect is obtained when verapamil plasma concentrations are between 100 and 400 ng/ml. Several chromatographic procedures for the determination of verapamil in biological fluids have been described ...

A potentiometric titration method for the determination of minoxidil based on its redox reaction with K2Cr2O7 is described. The best results were observed using 1.00 x 10-3 mol L-1 K2Cr2O7 and 1.00 x 10-2 mol L-1 minoxidil solutions, and the minoxidil as titrant in 2.00 mol L-1 H2SO4 medium. The method was applied to commercial samples and compared with the results from a chromatographic proced...

an efficient synthesis of polyhydroquinoline derivatives was reported via four-component coupling reactions of aldehydes, 1,3-dicarbonyl ketones (dimedone or 1,3-cyclohexanedione), ethyl acetoacetate or methyl acetoacetate and ammonium acetate in the presence of a catalytic amount of nanocrystalline tio2 under solvent free conditions. the reported method is mild, rapid and has the advantages su...

Concentrations of diphenylhydantoin in 364 plasma samples have been measured both by radioimmunoassay and with a recently developed gas-chromatographic method, which requires only 0.1 ml of plasma per determination. There was an excellent correlation between values obtained by the two methods (r = 0.986), and in only 11 plasma samples did the results differ by more than 20%. Of the investigated...

With this fluorometric method for measuring indocyanine green (ICG) in biological fluids, the limit of detection is an order of magnitude lower than for the traditional spectrophotometric procedure. The excitation and emission maxima are 780 and 810 nm, respectively. Agreement was excellent (r = 0.998) between direct results by this method and those by a liquid-chromatographic procedure with sp...

A gas-chromatographic procedure for acetaminophen is described in which the drug is chromatographed as the O-heptyl-N-methyl derivative. This derivative is prepared by a sequential alkylation procedure in which the phenolic hydroxyl group of the parent compound is alkylated off-column with heptyl iodide and the amide group is derivatized on-column by reaction with trimethylanilinium hydroxide. ...

An optimization method based on uniform design in conjunction with genetic algorithm is described. According to the proposed method, the uniform design technique was applied to the design of starting experiments, which can reduce the number of experiments compared with traditional simultaneous methods, such as simplex. And genetic algorithm was used in optimization procedure, which can improve ...