Analytical method development and validation studies for estimation of anti-psychotic drug (Olanzapine)

<p class="abstract"><strong>Background:</strong> Various sophisticated strategies have been raised in conformity with permit the fast separation and quantification about clue aspects concerning complex mixtures of biological matrix. These needs underscored the necessary of analytical instrumentation and the creation of new strategies.</p><p class="abstract"><strong>Methods:</strong> A rapid, accurate, precise, and simple UV then LC-MS/MS analytical methods has been flourished for the determination of Olanzapine (OLZ) in tablet formulation. </p><p class="abstract"><strong>Results:</strong> Chromatographic separation was conducted out on a Phenomenex 250×4.60 mm with an isocratic mobile phase consisting formic acid of 0.1% v/v in Methanol and water at a ratio regarding 92:08v/v and an aggregation run time of 2.5 min. The plasma Olanzapine concentrations were quantified the use of SCIEX API 3000 LC-MS/MS provision geared up along electro spray ionization cleft into the multiple reaction limit mode at m/z 313.4 to 256.3 for Olanzapine; and m/z 327.1 to 270.0 for clozapine respectively. Calibration requirements were organized into the range 5 ng/ml in conformity with 1000 ng/ml for Olanzapine. The effects had been unique and reproducible with the samples prepared by way of liquid-liquid extraction method using Tert-butyl methyl ether extraction in the course of approach improvement trials.</p><p class="AT"><strong>Conclusions:</strong> The novelty on its technique entails the improvement and validation by means of the usage of some quadrant easy pattern decontamination approach and the most sensitive technique with shortest analysis time.</p>

Theoretical study of hydroxyl radical (OH˙) induced decomposition of tert-butyl methyl ether (MTBE)

We have characterized the various pathways for OH radical (OH˙) induced decomposition of tert-butyl methyl ether (MTBE) and found an oxidative pathway that leads to complete degradation under the prerequisite that OH radicals are present in excess.

ALIPHATIC AND TRITERPENOIC PRODUCTS OF ETHER EXTRACTS SAPONIFICATION OF POPULUS NIGRA L.

Our investigation deals with extractives which content about 15% of whole biomass. The extracts obtained from poplar bark and foliage, and purified phytochemicals arising from these extracts, can find various applications, e.g., as biopharmaceuticals, food additives and nutraceuticals, biopesticides, and cosmetic products. Composition of neutral lipophylic compounds of poplar bark and foliage was studied as far as inflorescences of male and female plants and pollen. Tert-butyl methyl ether (TBME) was used as an extraction solvent for raw materials having all the advantages of diethyl ether, but devoid of its disadvantages. It does not form peroxides and does not create increased gas content due to the higher boiling point. TBME-extracts were investigated by gas chromatography–mass-spectrometry (GC-MS). We found more than 40 lipophilic neutral constituents from raw materials of poplar bark and foliage. 60 lipophilic neutral constituents from raw materials of florescences and pollen including alkanes, sterols, aliphatic and triterpenoic alcohols as far as 34 acidic compounds were identified by GC-MS. The content of inflorescences and pollen extracts differs from bark and foliage constituents.

METHODOLOGICAL RECEPTION FOR DETERMINATION OF DICAMBA RESIDUES IN SOYBEANS BY GC-MS

Introduction. In this paper, there are presented results of investigations on the development and validation of the method for the determination of dicamba residues in import foodstuff (soybeans). The identification and quantitative determination of dicamba are performed by capillary gas-liquid chromatography with mass-selective detection (ionization-electron impact). Material and methods. The stages of sample preparation include four steps as extraction with acidified acetonitrile, followed by the filtration and evaporation; freezing the sample with filtration and evaporation; dissolving the dry residue in a mixture of acetone: water (1:20); purification by repeated redistribution in a system of immiscible solvents under varying the pH of the aqueous medium (pH 9-10: dichloromethane, hexane, pH 2: hexane-tert-butyl methyl ether). The chromatographic measurement was preceded by the derivatization of the acid to the corresponding methyl ester by the treatment with a solution of diazomethane in diethyl ether Results. The lower limit of the quantitative evaluation of dicamba in samples of soybean beans is of 0.01 mg/kg, the signal-to-noise ratio at the detection limit accounts of 20:1. The completeness of extraction of dicamba, established on the basis of analysis of model samples with the introduction of a substance at four points within the defined range, amounted to 85-95%. The average quadratic deviation of the repetition varies in the range of 3.3-4.9%. Discussion. The use of diethyl ether containing dibutylhydroxytoluene (6 ppm) as a stabilizer, as well as the interfering effect of phthalates, led to the formation of poorly resolved peaks of the methyl ester of dicamba, dibutylhydroxytoluene, and dibutyl phthalate. The combination of the use of different methods of data collection (in the scanning mode and in the mode of recording individual ions) made it possible to identify these components. Replacement of the used diethyl ether, as well as variation of chromatographic conditions, for separation of dicamba and phthalate peaks, made it possible to achieve the necessary selectivity of detection of the analyte.

London dispersion as important factor for the stabilization of (Z)-azobenzenes in the presence of hydrogen bonding

The understanding and control of the light-induced isomerization of azobenzenes as one of the most important classes of molecular switches is crucial for the design of light-responsive materials using this entity. Herein, we present the stabilization of metastable (Z)-azobenzenes by London dispersion interactions, even in the presence of comparably stronger hydrogen bonds in various solvents. The Z→E isomerization rates of several N-substituted 4,4′-bis(4-aminobenzyl)azobenzenes were measured. An intramolecular stabilization was observed and explained by the interplay of intramolecular amide and carbamate hydrogen bonds as well as London dispersion interactions. Whereas in toluene, 1,4-dioxane and tert-butyl methyl ether the hydrogen bonds dominate, the variation in stabilization of the different substituted azobenzenes in dimethyl sulfoxide can be rationalized by London dispersion interactions. These findings were supported by conformational analysis and DFT computations and reveal low-energy London dispersion forces to be a significant factor, even in the presence of hydrogen bonds.