The Experts below are selected from a list of 71127 Experts worldwide ranked by ideXlab platform
Hsinlung Wu - One of the best experts on this subject based on the ideXlab platform.
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high performance liquid Chromatographic Analysis of perhexiline as a fluorescent derivative
2010Co-Authors: Peiyi Huang, Hsinlung WuAbstract:Perhexiline is an effective drug for angina pectoris, butprolong use of the drug mayinduce toxicity. A simpleandsensitivemethodwasdevelopedformonitoringthedrugtoavoidovermedication.Themethod is based on derivatizing perhexiline with a fluorescent reagent (2-napththoxy) acetyl chloride. The resulting derivative is highly responsive to a fluorimetric detector (ex = 230 nm, em = 347 nm). The lower quantitation limit of the method is attainable at 0.3Mwith a detection limitof about30 nM(S/N = 3 with 10 L injected). The method was applicable to the Analysis of perhexiline in spiked plasma.
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fluorimetric liquid Chromatographic Analysis of amantadine in urine and pharmaceutical formulation
2005Co-Authors: Hsinlung WuAbstract:Abstract A simple and sensitive liquid Chromatographic method is described for the Analysis of amantadine and memantine. The method is based on the derivatization of amantadine and memantine extracted from alkalified samples with (2-naphthoxy)acetyl chloride at mild conditions. The resulting derivatives were analyzed by isocratic HPLC with a fluorimetric detector (λex, 227 nm; λem, 348 nm). The linear range for the determination of amantadine or memantine spiked in urine (1.0 ml) was 1.0–10. 0 nmol with a detection limit of about 0.2 nmol (S/N = 3; injected sample 20 μl). Only amantadine preparations are available on our local market, and application of the method to the Analysis of amantadine in formulation and in the urine of a dosed subject was demonstrated and proved feasible. Quantitation of AT in tablets or capsules is capable in the linear range of 2.0–50.0 μM. Toluene was used as the solvent for extracting amantadine or memantine in samples and the resulting toluene extract was directly subjected to subsequent derivatization without solvent replacement leading to a simpler analytical procedure.
Hava Schneider - One of the best experts on this subject based on the ideXlab platform.
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liquid Chromatographic Analysis of physostigmine salicylate and its degradation products
1999Co-Authors: Shai Rubnov, Daniel Levy, Hava SchneiderAbstract:A simple stability-indicating HPLC assay has been developed for physostigmine salicylate, capable of following its degradation. A 250×5 mm i.d. column packed with 10 μm Bondapak C18 was used, with a mobile phase of acetonitrile–ammonium acetate (pH 6.0; 0.1 M) (50:50, v/v) and flow rate 1.2 ml min−1. All peaks are eluted in <10 min and the method has good precision. The optimum wavelength for detection of degradation products is 305 nm. Application of the assay for a commercial preparation of physostigmine salicylate for injection is presented.
J Gudej - One of the best experts on this subject based on the ideXlab platform.
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computer aided optimization of high performance liquid Chromatographic Analysis of flavonoids from some species of the genus althaea
1991Co-Authors: Tadeusz H Dzido, Edward Soczewinski, J GudejAbstract:DryLab G software was used for the optimization of gradient elution programs in reversed-phase high-performance liquid chromatography applied to the Chromatographic Analysis of flavonoids present in marsh-mallow (Althaea officinalis). The optimization experiments were carried out for a mixture of eight standard solutes (isolated previously from the plant) and then applied to an extract from the flowers of marsh-mallow. Computer simulation experiments allowed convenient analytical conditions to be chosen. The use of two modifiers, methanol and acetonitrile, made the identification of separated components more certain. Good agreement between simulated and experimental chromatograms was obtained.
Ivan Radež - One of the best experts on this subject based on the ideXlab platform.
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high performance liquid Chromatographic Analysis of mevinolin as mevinolinic acid in fermentation broths
1995Co-Authors: Jožica Friedrich, Mateja žužek, Mojca Bencina, Aleksa Cimerman, Ales Strancar, Ivan RadežAbstract:Abstract High-performance liquid Chromatographic Analysis of mevinolin in fermentation broth was initially performed after addition of acid and extraction with methanol using a mobile phase at pH 3.0. Under such conditions mevinolin was present in three different forms: as a lactone, as the corresponding s-hydroxy acid (mevinolinic acid) and as its methyl ester. To achieve accurate and reproducible results the method was modified such that only one form was present: mevinolinic acid. The fermentation broth samples were adjusted to pH 7.7 before the extraction with methanol, and the pH of the mobile phase was adjusted to 7.7 as well. For the separation a 250 × 4 mm I.D. column, termostated at 40°C, packed with Spherisorb ODS 2 of 5 μm particle size was used. Under these conditions mevinolin was detected at 237 nm as a single peak of a s-hydroxy acid, which has the lowest retention time of all three forms.
Douglas Wagner Franco - One of the best experts on this subject based on the ideXlab platform.
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qualitative and quantitative high performance liquid Chromatographic Analysis of aldehydes in brazilian sugar cane spirits and other distilled alcoholic beverages
1997Co-Authors: Ronaldo Ferreira Do Nascimento, Juliana Bilhar C Marques, Benedito Dos Santos Lima Neto, Denis De Keukeleire, Douglas Wagner FrancoAbstract:A study is presented on the high-performance liquid Chromatographic Analysis of eighteen aldehydes in Brazilian sugar cane spirits and other international brandies. The aldehydes were separated by reversed-phase high-performance liquid chromatography as 2,4-dinitrophenylhydrazones (DNPHs). A very good Chromatographic separation was achieved for eighteen different aldehyde-DNPHs. The proposed methodology is quite simple and not very time-consuming. Ten aldehydes were identified in 75 beverages and quantified using the external standard method with UV detection at 365 nm. A detailed knowledge of the aldehyde content should significantly contribute to improving the quality control of distilled spirits.