International Journal of Chemical and Analytical Science最新文献

Background

Iloperidone (ILP) is a second-generation atypical antipsychotic agent and idebenone (IDB), a synthetic analogue of coenzyme Q10 is an important cell membrane antioxidant. No validated analytical method for simultaneous determination of ILP and IDB in rat plasma has been reported till date.

Objective

To develop and validate a simple reversed phase high performance liquid chromatography method for simultaneous determination of iloperidone and idebenone in rat plasma.

Methods

A liquid–liquid extraction method was used for deproteination of plasma samples using methanol as an extraction solvent. Chromatographic separations were done using isocratic conditions. Mobile phase containing acetonitrile and 0.025 M KH₂PO₄, pH 6 (60:40) at a flow rate of 1 mL/min was utilized for efficient separation. The UV detector was set at 277 nm. Risperidone was used as an internal standard.

Results

The limits of detection (LOD) for iloperidone and idebenone were 10 and 20 ng/ml, while the limits of quantification (LOQ) were 30 and 35 ng/ml, respectively. The standard curves for iloperidone and idebenone in plasma were linear over the range of 0.05–20 μg/ml, with the correlation coefficients of 0.9993 and 0.9985, respectively. All the validation parameters, such as accuracy, intra and inter-day precision were within the required limits. The samples were stable at −80 °C and −20 °C as compared to 4 °C storage temperature when subjected to repeated freeze–thaw cycles.

Conclusion

The proposed method proves to be a sensitive method because of its potential to simultaneously determine iloperidone and idebenone in rat plasma in a single HPLC run.

A simple, sensitive and specific liquid chromatographic method with UV detection (230 nm) was developed for the simultaneous estimation of hydrochlorothiazide, amlodipine and losartan in tablet dosage form and telmisartan as an internal standard. Separation was achieved with a phenomenex luna 5μ CN 100R, 250 × 4.60 mm 5 micron size column, ambient temperature with a low pressure gradient mode with mobile phase containing acetonitrile, water and 0.4% of potassium dihydrogen phosphate buffer pH 2.7 adjusted with orthophosphoric acid (45:35:20). The flow rate was 1 mL min⁻¹ and eluent was monitored at 230 nm. The selected chromatographic conditions were found to effectively separate hydrochlorothiazide, amlodipine and losartan with retention time of 3.9, 4.9 and 5.8 min respectively. The linearity range of hydrochlorothiazide, amlodipine and losartan found in the range of 12.5–62.5 μg ml⁻¹, 2.5–12.5 μg ml⁻¹ and 50–250 μg ml⁻¹ respectively. The proposed method was found to be accurate, precise, reproducible and specific and it can also be used for routine quality-control analysis of these drugs in combination tablets.

Aim

The aim of the present study is to synthesize the metal nanoparticles by the green chemical approaches due to their novel optical, catalytic, hydrogen storage, bio-imaging and electrochemical applications.

Materials and methods

1 mM of PdCl₂ and Piper betle leaf broth (10:1) are used to synthesize the stable Pd⁰ nanoparticles.

Results

The structural characterizations studied by UV-Vis Spectroscopy, XRD and FTIR-Spectroscopy. The morphology, particle distribution and size of the palladium nanoparticles were studied by TEM and SAED Techniques. The bioactivity demonstrated by synthesized PdNPs was lead to an excellent clinical use as anti-fungal material.

Background/Aims

Kaempferia rotunda (Zingiberaceae), known as kunci pepet or kunir putih in Indonesia, has been traditionally used in abdominal pain, sputum laxative, wounds and diarrhea colic disorder. This study was conducted to isolate and to investigate antimutagenic activity of some flavanones from K. rotunda.

Methods

The milled dried rhizoma of K. rotunda (3 kg) was extracted exhaustively with methanol. The methanol extract was partitionated three times by n-hexane, chloroform, and ethyl acetate respectively. Each fraction was fractionated by vacuum liquid chromatography (VLC) and purified by column chromatography gravitation. Identification structures of all pure compounds were elucidated based on spectroscopic methods (UV, IR, and NMR) and compared to the spectroscopic previously reported data. Antimutagenic activity test was observed in vivo based on the number of micronucleated polychromatic cell erythrocytes (MNPCE) from male Balb-c mice (8–12 week) induced by cyclophosphamide.

Results

From the dried and milled rhizoma of K. rotunda, three known flavanones, namely 5-hydroxy-7-methoxyflavanone (1), 7-hydroxy-5-methoxyflavanone (2), and 5,7-dihydroxyflavanone (3) were isolated. The methanol extract and isolated flavanones from K. rotunda showed significant antimutagenic effect compared to control group.

Aims

Terpolymer (BPEDF) has been synthesized by the condensation of the monomers 2, 2′- biphenol, ethylene diamine and formaldehyde in 1:1:2 molar proportions in the presence of 2 M HCl as a catalyst.

Methods

The purity of newly synthesized resin has been tested and confirmed by the thin layer chromatography (TLC) technique. The structure of BPEDF has been elucidated on the basis of elemental analysis and various physicochemical techniques, i.e. FTIR, ¹HNMR, and UV–Visible spectral studies.

Result

Detailed thermal degradation study of the new terpolymer has been carried out to ascertain its thermal stability. The thermal degradation curve shows three decomposition steps (40–210 °C, 220–410 °C and 410 °C–900 °C). The thermal degradation curve was examined in order to determine their mode of decomposition, order of reaction, apparent activation energy, frequency factor, free energy change, entropy change and apparent energy change. Sharp–Wentworth and Freeman–Carroll methods have been used to calculate activation energies and thermal stability. The activation energy (25.84 KJ/mole⁻¹) calculated by using the Sharp–Wentworth method has been found to be in good agreement with that calculated by Freeman–Carroll method (23.11 KJ/mole⁻¹). The decomposition temperature is found to be 251 °C. The order of reaction (n) is found to be 0.95.

Aims/Background

Human sweet taste receptor structure is predicted and was further evaluate using experimental result. This would enable receptor-based docking and pharmacophore studies since no structure, experimental or predicted model, for complete subunits of human sweet taste receptor (hSTR) is available till date.

Methods

Different homology modelling as well as threading-based tools were employed for structure prediction of individual domains (amino terminal domain (ATD), cysteine rich domain (CRD) and transmembrane domain (TMD)) and complete subunit structure. Finally, complete subunits structure was built from combinations of individual domain models. These predicted models were validated and further evaluated using docking and interaction analysis of the experimentally studied sweet molecules.

Results/Conclusion

hSTR Modelling through threading based tools was of poor quality with the exception of ITASSER software that predicted models with greater than 90% residues in energetically favourable environment. Among homology based software, CPH Model, SWISS Model and Prime predicted hSTR model of acceptable quality with more than 95% residues in energetically favourable environment. This model can be used for receptor-based pharmacophore modelling or searching newer sweet molecules.