Authors:S.V. Mulgund, S. Anbazhegan, and S.Y. Gabhe
In the present study, the degradation behavior of Fenofibrate under different International Conference on Harmonization (ICH) suggested conditions was studied. Characterization of degradation products by liquid chromatography–tandem mass spectrometry (LC–MS/MS) studies in solution form was done, and the possible mechanism for the formation of degradants is discussed. Fenofibrate was subjected to different hydrolytic stress conditions and thermal stress condition (in solid form). Successful separation of drug from degradants was achieved on a C18 column using water–acetonitrile (25:75 v/v) as the mobile phase. Other high-performance liquid chromatography (HPLC) parameters were: flow rate, 1 mL min−1; detection wavelength, 286 nm; column temperature, 25 °C; and injection volume, 20 μL. The method was validated for linearity, precision, accuracy, robustness, and specificity and was stability-indicating one, based on the specificity studies. The drug degraded under acidic, basic, and oxidative hydrolytic stress while it was relatively stable towards neutral hydrolysis and thermal stress. The stressed samples were subjected to LC–MS/MS analysis. On the basis of spectral data, the structures of four degradation products and one interaction product were suggested. Degradation products were characterized to be isopropyl acetate, 2-[4-(4-chlorobenzoyl)phenoxy]-2-methyl propanoic acid, 4-hydroxy benzoic acid, and benzoic acid. The structure of one interaction product was proposed as methyl 2-[4-(4-chlorobenzoyl)phenoxy]-2-methylpropanoate.
Authors:Mona Al-Shehri, Mohamed Hefnawy, Hatem Abuelizz, and Adeeba Alzamil
the above mention techniques, and was therefore used in the pharmacokinetic study of letrozole.
For determination of PLB, there are few validated reversed-phase HPLC with photodiode array detection (RP-HPLC–PDA) methods for determination of PLB
Authors:Kazimierz Głowniak, Krystyna Skalicka, Agnieszka Ludwiczuk, and Katarzyna Jop
Plants of the
family are very rich in phenolic compounds. TLC, 2D TLC, and RP HPLC have been used for qualitative analysis of phenolic acids and flavonoids in the flowers of
L. Four aglycones, seven glycosides and eleven phenolic acids were identified in the plant, most for the first time. Quantitative analysis of phenolic compounds was also performed.
Authors:Erzsébet Háznagy-Radnai, Petra Léber, Enikő Tóth, Gábor Janicsák, and Imre Máthé
L. (Lamiaceae) contains the iridoids harpagide and acetylharpagide. The presence of other components, for example aucubin, can be revealed by TLC and RP HPLC. A readily applicable simple TLC-densitometric method for analysis of aqueous extracts of the plants has been established for comparative studies of aucubin-like iridoids in
Ultracentrifugation was used as a non-destructive method to separate dough into liquid, gel, gluten, starch and bottom phases. The protein composition in the different phases was investigated for dough prepared from spring wheat (Triticum aestivum L.). The SDS-PAGE, SE-HPLC and RP-HPLC methods were used for the analysis. The wheat protein composition of the liquid and gel phases consisted of albumins, globulins and traces of gliadins and glutenins. The gluten phase contained proteins extractable with all the extraction buffers used. A similar protein composition was found in the starch and bottom phases, but in considerably lower amounts. Specific LMW glutenin subunits were identified in the gluten phase by RP-HPLC. The albumin composition differed in the gel phase compared to the gluten and bottom phases. Differences in protein composition due to mixing methods were detected only for the albumin composition in the liquid phases.
Authors:J. Kuruc, M. Sahoo, J. Ločaj, and M. Hutta
Saturated aqueous solutions of nitrobenzene (in water, 0.1M nitric acid and 0.1M potassium hydroxide) were irradiated with60Co -rays in deaerated condition. Radiolytic products were analyzed using reverse phase-high performance liquid chromatography (RP-HPLC) and multicomponent UV-VIS spectrometry. With the aid of RP-HPLC retention times of the radiolytic products were found to be identical with those of isomeric nitrophenols, aminophenols and dinitrophenols. According to the primary information obtained from RP-HPLC and literature, we have chosen ten standards and eleven wavelengths for multicomponent UV-VIS analysis (linear multiparametric regression analysis) and the concentrations of nitrobenzene, nitrophenols, aminophenols and dinitrophenols in water, HNO3 and KOH solutions were calculated.G-values molecules/100 eV) of the radiolytic products and decomposition of nitrobenzene in aqueous solutionsG(-nitrobenzene) were calculated from the dependence of their concentrations with dose. Ph has relatively little influence on the decrease of concentration of nitrobenzene, but has strong influence on the product composition.
The adsorption isotherms of methanol in water solutions which were used as mobile phase in RP HPLC on adsorbents modified
with dimethyloctadecylchlorosilane were measured. On the basis of these isotherms the chemical composition of the stationary
phase as a function of the mobile phase concentration was determined. The influence of both those phases on retention factors
k′ of alkyl derivatives of benzene was discussed. It was stated that k′ of benzene and its derivatives decreases with the
various rate together with the increase of the methanol concentration in both phases. Quotient of volume coefficient corresponding
to a unit of adsorbed methanol (logk′/nsMe) decreases linearly.
Authors:H. Stephan, R. Berger, H. Spies, B. Johannsen, and F. Schmidtchen
Extraction of pertechnetate with bicyclic guanidinium compounds has been studied in the KTcO4-buffer-H2O/ligand-trichloromethane system. Extraction data of guanidinium ligands have been compared with trialkylmethylammonium (Aliquat
336), tetraphenylphosphonium and tetraphenylarsonium chloride. The lipophilicity of extractants investigated was determined
by RP-HPLC. The efficiency of pertechnetate extraction correlates with the lipophilicity of the guanidinium compounds. 1:1
complex formation in the organic phase was observed. The influence of hydroxide, chloride and bicarbonate on the pertechnetate
extraction has been investigated. Pertechnetate is extracted with great preference over OH−, Cl− and HCO3−, ions.
A simple and convenient chromatographic method of simultaneous separation, identification, and quantitative determination of thimerosal (TM) (preservative) and aluminum (adjuvant) in vaccines and pharmaceuticals by reversed phase highperformance liquid chromatography (RP-HPLC) with visible (VIS) detection was developed and validated. Due to postcolumn derivatization with dithizone, any interference from matrix was excluded. Similarly, a possibility of on-column decomposition of dithizonates was eliminated. Evaluated detection limits were 0.3 μg TM and 3.0 μg Al, which correspond to the smallest, but possible to recognize, visible peak.
Authors:A. Al Asmari, H. A. Khan, and R. A. Manthiri
We present the comprehensive chromatographic profiles of three scorpion species, Androctonus crassicauda, Androctonus bicolor, and Leiurus quinquestriatus, commonly inhabited to Middle East regions. Their venoms were milked by electrical stimulation, diluted with distilled water, properly mixed and centrifuged to separate the mucus from venom. The clear supernatant was filtered and the protein concentration was determined. Pre-diluted venoms were chromatographed on FPLC (fast protein liquid chromatography) and RP-HPLC (reversed-phase high-performance liquid chromatography) and the fractions were collected for molecular weight determination. Both techniques have resulted clearly distinguishable chromatographic patterns that can be used for identification of scorpion species and having a quick indication of venom toxicity.