Current Issue : October - December Volume : 2018 Issue Number : 4 Articles : 6 Articles
The objective of this study was to develop and validate a method for quantitative analysis of rivastigmine hydrogen tartrate (RHT)\nin dual-ligand polymeric nanoparticle formulation matrices, drug release medium, and cellular transport medium. An isocratic\nHPLC analysis method using a reverse phase C18 column and a simple mobile phase without buffer was developed, optimised, and\nfully validated. Analyses were carried out at a flow rate of 1.5 mL/min at 50�°C and monitored at 214 nm. This HPLC method\nexhibited good linearity, accuracy, and selectivity. The recovery (accuracy) of RHTfrom all matrices was greater than 99.2%. The\nRHTpeak detected in the samples of a forced degradation study, drug loading study, release study, and cellular transport study was\npure and free of matrix interference. The limit of detection (LOD) and limit of quantification (LOQ) of the assay were 60 ng/mL\nand 201 ng/mL, respectively. The method was rugged with good intra- and interday precision. This stability indicating HPLC\nmethod was selective, accurate, and precise for analysing RHT loading and its stability in nanoparticle formulation, RHTrelease,\nand cell transport medium....
The absolute configuration of retroflexanone (1) and a closely related phlorogluinol (2) was\nestablished using the advanced Mosher method and by application of HPLC-NMR. HPLC-NMR\npermitted a small scale Mosher method analysis to be carried out on these unstable phloroglucinols....
2-Ethyl-3,6-dimethylpyrazine (EDMP) was an alarm pheromone component isolated from\nthe mandibular gland of the red imported fire ant, Solenopsis invicta Buren. Several pyrazine analogues\nhave been previously found to elicit significant alarm responses in S. invicta workers. This study\naimed to separate the commercially available 2-ethyl-5(6)-methylpyrazine (EMP), i.e., a mixture of\n2-ethyl-6-methylpyrazine (2E6MP) and 2-ethyl-5-methylpyrazine (2E5MP), and to examine both\nelectroantennogram (EAG) and behavioral responses of S. invicta workers to EMP and the purified\nisomers. HPLC separations were achieved using a polysaccharide chiral stationary phase (Chiralpak\nAD-H) column with both mobile phases: Cyclohexane/isopropanol, and hexane/isopropanol. A ratio\nof 99:1 was selected for the separation of EMP at semipreparative level. The structures of the\nisomers obtained through the cyclohexane/isopropanol mobile phase were confirmed by detailed\nanalyses of 2D-HSQC- and -HMBC-NMR data. The two isomers showed differential methine Cââ?¬â??H\ncorrelations evidenced by 2D-HMBC-NMR spectra. The two concentrated fractions obtained through\nhexane/isopropanol mobile phase were subjected to EAG test and behavioral bioassay on S. invicta\nworkers. The two HPLCâË?â??purified isomers, 2E6MP and 2E5MP, and their mixture (1:1) at same\ndose elicited similar EAG and alarm responses, indicating that these two isomers are equally active.\nThe 2D-NMRâË?â??spectroscopic characterization, and electrophysiological and alarm activities of 2E6MP\nand 2E5MP were reported here for the first time....
Rosemary (Rosmarinus officinalis), garden sage (Salvia officinalis), summer savory (Satureja hortensis), laurel (Laurus nobilis), and\nother aromatic plants were put in olive oil and exposed to ultrasounds for different duration. Filtrated oils were dissolved in\ncyclohexane, and UV-Vis measurements were carried out. Absorbance values corresponding to chlorophylls, carotenoids,\nflavonoids (370 nm), and polyphenols (around 300 nm) were measured. In addition, for some samples, total phenols were\ndetermined using Folin-Denis reagent and compared with the similar maceration procedure in water solvent (instead of olive\noil). Maceration without ultrasound in olive oil for each plant was also compared with ultrasound-assisted extraction. The\nresults show that significant amount of aromatic content can be extracted in olive oil by applying ultrasounds for only few\nminutes, especially for Salvia officinalis powder. The use of UV-Vis measurements is simple but enough to examine the extent\nof phenol content extraction through such maceration procedure....
Qing-Hua-Yu-Re-Formula (QHYRF), a new herbal preparation, has been extensively used for treating diabetic cardiomyopathy.\nHowever, the chemical constituents of QHYRF remain uninvestigated. In the present study, rapid ultrahigh-performance liquid\nchromatography coupled with quadrupole-time-of-flight mass spectrometry (UHPLC-Q-TOF/MS) was used to qualitatively\nanalyze the components of QHYRF. Qualitative detection was performed on a Kromasil C18 column through the gradient elution\nmode, using acetonitrile-water containing 0.1% formic acid. Twenty-seven compounds were identified or tentatively characterized,\nincluding 12 phenolic acids, nine monoterpene glycosides, two flavonoids, three iridoids, and one unknown compound.\nAmong these, six compounds were confirmed by comparing with standards. A high-performance liquid chromatography (HPLC)\nmethod was developed to simultaneously determine the following six active components in QHYRF: danshensu, paeoniflorin,\nacteoside, lithospermic acid, salvianolic acid B, and salvianolic acid C. These HPLC chromatograms were monitored at 254, 280,\nand 320 nm. The method was well validated with respect to specificity, linearity, limit of detection, limit of quantification,\nprecision, stability, and recovery. The HPLC-UV method was successfully applied to 10 batches of QHYRF....
A simple, rapid, accurate, precise and reproducible RP-HPLC method for the estimation of rizatriptan benzoate in bulk and tablet dosage form was developed and validated as per ICH guidelines. The separation was done using Enable C18 G 150 x 4.6 mm, 5µ column. The mobile phase (water and methanol; 80:20% v/v) was pumped at 1.0 ml/min and effluent was detected at 225 nm using a PDA detector. The retention time was 2.417 min and the method produced linear response in the concentration range of 1-10 µg/ml (r2 - 0.999). In recovery studies, %RSD from reproducibility was found to be below 2%. LOD and LOQ were 0.34 µg/ml and 1.036 µg/ml respectively. The developed RP-HPLC method was found to be effective, sensitive and specific for the estimation of rizatriptan benzoate in bulk and tablet dosage form....
Loading....