N-methyl-N-((1-methyl-5-(3-(1-(2-methylbenzyl)piperidin-4-yl)propoxy)-1H-indol-2-yl)methyl)prop-2-yn-1-amine, a new cholinesterase and monoamine oxidase dual inhibitor

On the basis of N-((5-(3-(1-benzylpiperidin-4-yl)propoxy)-1-methyl-1H-indol-2-yl)methyl)-N-methylprop-2-yn-1-amine (II, ASS234) and QSAR predictions, in this work we have designed, synthesized, and evaluated a number of new indole derivatives from which we have identified N-methyl-N-((1-methyl-5-(3-(1-(2-methylbenzyl)piperidin-4-yl)propoxy)-1H-indol-2-yl)methyl)prop-2-yn-1-amine (2, MBA236) as a new cholinesterase and monoamine oxidase dual inhibitor.PostprintPostprintPeer reviewe

Densitometric determination of metoprolol tartrate in pharmaceutical dosage forms

This paper describes a simple densitometric method for the determination of metroprolol tartrate in tablets and ampoules. After separation on silica gel GF254 plates, using acetone-methanol-triethylamine as the mobile phase for the tablets and acetone-triethylamine for ampoules, the chromatographic zones corresponding to the spots of metoprolol were scanned. Quantitation was performed using a computer-controlled Camag TLC scanner and applying five-point calibration with polynomial regression. The calibration function was established in the ranges 1-28 mu g for tablets and 1-9 mu g for ampoules. The results obtained are precise and reproducible, with recovery values of 99.1-99.4%

Spectrophotometric Determination of Methandienone in Tablets Using 1.4-Dihydrazinophthalazine

A simple and sensitive method for the determination of methandienone in tablets using 1.4-dihydrazinophthalazine as the reagent is presented. The yellow coloured dihydralazinhydrazone shows the maximum at 401 nm and molar absorptivity of 1.5x104 1 mol-1cm-1. Beer's law is obeyed up to 16 μ g/ml methandienone. The method applied for the assay of methandienone in dosage form gave precise and reproducible results; recovery was 98.57. and relative standard deviation was 1.57%

Spectrophotometric determination of desoximetasone in ointment using 1,4-dihydrazinophthalazine

The proposed method is based on coloured hydrazone formation with 1,4-dihydrazinophthalazine as a reagent. Heating at 85 degrees C for 2 h was found necessary to ensure optimal hydrazone formation in the presence of hydrochloric acid. The yellow hydrazone product has an absorption maximum at 380 nm. A linear relationship between absorbance and concentration was established in the concentration range 3.19 x 10(-6)-3.19 x 10(-5) mol l(-1) (the regression equation was y = 0.013 167 3 + 0.019 025 9x; correlation coefficient r = 0.9991; n = 6). The detection limit was 1.2 mu g ml(-1) (molar absorptivity found was 1.97 x 10(4) l mol(-1) cm(-1)). The reliability of the proposed method was checked at three different concentrations; the relative standard deviation (RSD) varied from 1.03 to 2.01%. The described method applied to the determination of desoximetasone in ointment gave precise and reproducible results; the recovery was 98.55% with RSD = 2.40% (n = 10).5th International Symposium on Drug Analysis, Sep 12-15, 1995, Louvain, Belgiu

First-order UV-derivative spectrophotometry in the analysis of omeprazole and pantoprazole sodium salt and corresponding impurities

The first-order UV-derivative spectrophotometry, applying zero-crossing method was developed for the determination of omeprazole (OM), omeprazole sulphone (OMS), pantoprazole sodium salt (PANa), and N-methylpantoprazole (NPA) in methanol-ammonia 4.0% v/v, where the sufficient spectra resolutions of drug and corresponding impurity were obtained, using the amplitudes D-1(304), D-1(307), D-1(291.5) and D-1(296.5), respectively. Method showed good linearity in the ranges ( mug ml(-1)): 1.61-17.2 for OM; 2.15-21.50 for OMS; 2.13-21.30 for PANa and 2.0-20.0 for NPA, accuracy and precision (repeatability and reproducibility). The experimentally determined values of LOD (mug ml(-1)) were 1.126; 0.76; 0.691 and 0.716 for OM, OMS, PANa and NPA, respectively. The obtained values of 2.91% w/w for OMS and 3.58% w/w for NPA in the presence of their parent drug, by applying the method of standard additions, point out the usage of the proposed method in stability studies. Zero-crossing method in the first-order derivative spectrophotometry showed the impurity-drug intermolecular interactions, due to the possible intermolecular hydrogen bonds, confirmed by divergences of experimentally obtained amplitudes for impurities OMS and NPA in comparison to expected values according to regression equations of calibration groups

HPTLC assay of cephalexin and cefaclor in pharmaceuticals

A simple and reliable HPTLC method for the simultaneous determination of cephalexin and cefaclor is developed and validated. The methanol-ethyl acetate-acetone-water (5:2.5:2.5:1.5 v/v/v/v) solvent system is used for the quantitative evaluation of chromatograms. The chromatographic zones, corresponding to the spots of cephalexin and cefaclor on the silica gel plates, are scanned in the reflectance/absorbance mode at 265 nm. The method is found to be reproducible and convenient for the quantitative analysis of cephalexin and cefaclor in its dosage forms

Densitometric determination of omeprazole, pantoprazole, and their impurities in pharmaceuticals

A method has been developed for separation of omeprazole and pantoprazole, and their impurities omeprazole sulfone and N-methylpantoprazole, by HPTLC. The mobile phase chloroform-2-propanol-25% ammonia-acetonitrile, 10.8 + 1.2 + 0.3 + 4 (v/v), enables good resolution of large excesses of the drugs from the possible impurities. Regression coefficients (r > 0.998), recovery (90.7-120.0%), and detection limit (0.025-0.05%) were validated and found to be satisfactory. The methods is convenient for quantitative analysis and purity control of the compounds

Spectrophotometric determination of bifonazole in pharmaceutical formulations using bromphenol blue

A sensitive spectrophotometric method for the determination of bifonazole is described. Bifonazole was treated with bromphenol blue (BPB) in the presence of citrate buffer (pH 2.5; μ = 0.23). The formed ion-pair complex was extracted with chloroform. By using spectrophotometric measurements, Job's and Bent-French's methods, it was found that bifonazole and BPB formed an ion-pair complex with the absorption maximum at 414 nm (molecular ratio of bifonazole BPB = 1:2) and molar absorptivity 2.23 x 104 L mol-1 cm-1. Beer's law was obeyed up to 2.5 μg ml-1. The proposed method was applied for determination of bifonazole in pharmaceutical formulations. Statistical analysis of the results obtained showed that the proposed method has good reproducibility and precision

UV derivative spectrophotometric study of the photochemical degradation of nisoldipine

The photodecomposition of nisoldipine ((+/-)3-isobutyl-5-methyl-1,4-dihydro-2,6-dimethyl-4-(2-nitrophenyl)-pyridine-3,5-dicarboxylate), whereby its 4-(2-nitrosophenyl) pyridine analogue is obtained as the photolytic product, was investigated under daylight exposure by means of UV derivative spectrophotometry. The optimal instrumental parameters (120 nm/min scan speed: 2 nm slit width; Delta lambda = 10 nm and 5 s response time) for analogue derivative spectra were established for amplitudes D-1(285) and D-2(291) (measured to the baseline) of the nitroso analogue assay, as well as for D-1(386) of the parent compound-nisoldipine assay. Using the first-order derivative spectrum, the minimum detectable amount of nitroso analogue in the presence of nisoldipine was equivalent to an impurity level of 5% and by the second-order derivative spectrum, the determination limit was equivalent to an impurity level of 2%. The degradation of nisoldipine followed within 30 days and the calculated maximal degradation rate was 1.6% per day for nisoldipine raw material, but significantly lower values of 0.19 and 0.15% per day were obtained for Nisoldin(R) tablets (10 and 5 mg, respectively). (C) 2000 Elsevier Science S.A. All rights reserved