piperidines and triethylamine

Switchable-hydrophilicity solvent liquid-liquid microextraction and dispersive liquid-liquid microextraction were compared for the extraction of piperine from Piper nigrum L. prior to its analysis by using high-performance liquid chromatography with UV detection. Under optimum conditions, limits of detection and quantitation were found as 0.2-0.6 and 0.7-2.0 μg/mg with the two methods, respectively. Calibration graphs showed good linearity with coefficients of determination (R

Topics: Alkaloids; Benzodioxoles; Chromatography, High Pressure Liquid; Cyclohexylamines; Ethylamines; Food Contamination; Hydrophobic and Hydrophilic Interactions; Liquid Phase Microextraction; Piper nigrum; Piperidines; Polyunsaturated Alkamides; Solvents; Spectrophotometry, Ultraviolet; Ultraviolet Rays

The present research project involves development and validation of a stability-indicating HPTLC method for the estimation of naratriptan-HCl in their pharmaceutical dosage forms and its content uniformity testing. Naratriptan-HCl was subjected to alkaline, acidic, oxidative, neutral, thermal (dry heat) and photo-degradation conditions. The chromatographic separation was carried out using a precoated silica gel G 60 F254 TLC plate as the stationary phase and dichloromethane-toluene-methanol-triethylamine (4 : 4 : 2 : 1, v/v/v/v) as the mobile phase. The spots of NRT-HCl and its degradation products were detected at 290 nm. The Rf value of NRT-HCl was found to be 0.60 ± 0.02. The linearity was obtained in the range of 100-500 ng/spot. The limit of detection and limit of quantitation were found to be 6.07 ng/spot and 18.41 ng/spot, respectively. The percentage recovery was found in the range of 98.87-99.55%. NRT-HCl was degraded under acidic, alkaline and oxidative conditions while stable under photolytic, neutral and dry heat conditions. The developed method was applied for estimation of naratriptan-HCl in marketed formulations and its content uniformity testing.

Topics: Chromatography, Thin Layer; Drug Stability; Ethylamines; Hydrogen-Ion Concentration; Limit of Detection; Methanol; Methylene Chloride; Oxidation-Reduction; Piperidines; Reproducibility of Results; Solvents; Tablets; Toluene; Tryptamines; Vasoconstrictor Agents

The reactivity of phosgene and perfluoroisobutylene (PFIB) towards 1,2-bis-nucleophiles was exploited to allow determination of these gases in air samples. 2-Aminothiophenol (ATP), 3,4-dimercaptotoluene (DMT) and 2-hydroxymethylpiperidine (HMP) were evaluated as bis-nucleophiles capable of forming thermally-stable derivatives with phosgene and PFIB when loaded with triethylamine onto Tenax TA. Experimental design was used to optimise thermal desorption conditions. Detection limits in the low ngm(-3) range were observed for the five derivatives investigated. This work represents the most sensitive analytical method for trace level quantitation of phosgene and PFIB published to date.

Topics: Air; Aniline Compounds; Chemical Warfare Agents; Ethylamines; Fluorocarbons; Gas Chromatography-Mass Spectrometry; Inhalation Exposure; Phosgene; Piperidines; Sensitivity and Specificity; Sulfhydryl Compounds; Toluene

The acceptor character of iron violurate complex was studied by examining the electronic, vibrational and 1H-nmr spectra of the charge transfer molecular complexes formed between the iron violurate as pi-acceptor and some amines as n-donors. Elemental analysis and spectral results establishes 1:2 stoichiometry of the adducts. The study has been conducted at different temperatures. Values of delta G degree, delta H degree and delta S degree have been calculated from the self-consistent values of the formation constants (KCT). Ionization potentials of the donors have been calculated and the solvent effect on the KCT values is discussed. The antibacterial and antifungal effects of the molecular complexes were studied.

Topics: Amines; Anti-Infective Agents; Antifungal Agents; Barbiturates; Diethylamines; Drug Evaluation, Preclinical; Ethylamines; Piperidines; Solvents; Spectrophotometry, Ultraviolet; Structure-Activity Relationship; Thermodynamics; Vibration