Search results for "DISCOVERY"
showing 10 items of 4119 documents
Determination of barbiturates in urine by micellar liquid chromatography and direct injection of sample.
2000
Abstract A liquid chromatographic procedure for the determination of six barbiturates (barbital, diallyl barbituric acid, phenobarbital, butabarbital, amobarbital and pentobarbital) in urine samples is described. The proposed system uses a Spherisorb octadecyl-silane ODS-2 C 18 analytical column and a guard column of similar characteristics. The UV detector was set at 240 nm. A study to select adequate composition of the micellar mobile phase for the separation of these compounds in urine samples is performed. Maximum resolution was achieved with a 0.07 M sodium dodecylsulphate-0.3% propanol at pH 7.4 eluent. Limits of detection at 240 nm were ranged between 0.13 μg ml −1 for diallyl barbit…
Design and synthesis of new trehalose-conjugated pentapeptides as inhibitors of Aβ(1-42) fibrillogenesis and toxicity
2009
Aggregation of the amyloid A? peptide and its accumulation into insoluble deposits (plaques) are believed to be the main cause of neuronal dysfunction associated with Alzheimer's disease (AD); small molecules that can interfere with the A? amyloid fibril formation are therefore of interest for a potential therapeutic strategy. Three new trehalose-conjugated peptides of the well known ?-sheet breaker peptide iA?5p,were synthesized. The disaccharide was covalently attached to different sites of the LPFFD peptide chain, i.e. at the N-terminus, C-terminus or at the Asp side chain. CD spectroscopy in different solvents was used to assess changes in the peptide conformation of these compounds. Th…
H2-Antihistaminika, 36. Mitt. Isolamtidin und Analoge
1987
Isolamtidin (9a), ein Stellungsisomer des Lamtidins (8a), sowie die analogen N3-substituierten 1-Methyl-1H-1,2,4-triazol-3,5-diamine 9e-i, k wurden durch spezifische Synthese dargestellt und am isolierten Meerschweinchenvorhof und an der histaminstimulierten Sauresekretion der narkotisierten Ratte auf H2-antagonistische Wirkung untersucht. H2-Antihistaminics, XXXVI: Isolamitidine and Analogues Isolamitidine (9a), a position isomer of lamtidine (8a), as well as the analogous N3-substituted 1-methyl-1H-1,2,4-triazole-3,5-diamines 9e-i, k were prepared and tested for H2-antagonistic activity on the isolated guinea-pig atrium and towards the histamine-stimulated acid secretion of the anaestheti…
Novel Insights and Therapeutical Applications in the Field of Inhibitors of COX-2
2004
The discovery of the two isoenzymes COX-1 and COX-2 and the knowledge of their function, localisation and regulation has initiated the development of COX-2 selective inhibitors (coxibs). Inducible COX-2 at the peripheral site of inflammation has been detected in the early 1990s, the involvement of recently detected spinal COX-2 has led to new insights into mechanisms of pain and may explain analgesic and antipyretic properties of COX-2 selective inhibitors. The coxibs rofecoxib and celecoxib have been introduced into therapy and seem to offer some advantages over the classical non-selective NSAIDs. The search for new COX-2 inhibitors is going on, the development of etoricoxib and lumiracox…
Spectrophotometric determination of promazine with an oxidative column in FIA manifolds
1992
Abstract A simple flow-injection spectrophotometric method for the determination of promazine is described. The two proposed procedures are based on the oxidation of analyte with a manganese dioxide column. Concentrations of promazine in the ranges 2–20 and 1–6 are determined with a relative standard deviation of 1.0%. The injection rates are 62 and 80 samples h −1 , respectively. The influence of foreign species and the determination of promazine in a pharmaceutical formulation are also reported.
Application of solid-phase microextraction combined with derivatization to the enantiomeric determination of amphetamines.
2005
Abstract The utility of combining chiral derivatization and solid-phase microextraction (SPME) for the enantiomeric analysis of primary amphetamines by liquid chromatography has been investigated. Different derivatization/extraction strategies have been evaluated and compared using the chiral reagent o -phthaldialdehyde (OPA)– N -acetyl- l -cysteine (NAC) and fibres with a Carbowax-templated resin coating. Amphetamine, norephedrine and 3,4-methylenedioxyamphetamine (MDA) were used as model compounds. On the basis of the results obtained, a new method is presented based on the derivatization of the analytes in solution followed by SPME of the OPA–NAC derivatives formed. The proposed conditio…
Comparison between micellar liquid chromatography and capillary zone electrophoresis for the determination of hydrophobic basic drugs in pharmaceutic…
2007
[EN] The determination of highly hydrophobic basic compounds by means of conventional reversed-phase liquid chromatographic methods has several drawbacks. Owing to the characteristics of micellar liquid chromatography (MLC) and capillary electrophoresis (CE), these techniques could be advantageous alternatives to reversed-phase chromatographic methods for the determination of these kinds of compounds. The objective of this study was to develop and compare MLC and CE methods for the determination of antipsychotic basic drugs (amitryptiline, haloperidol, perphenazine and thioridazine) in pharmaceutical preparations. The chromatographic determination of the analytes was performed on a Kromasil…
Relationship between particle size and dissolution rate of bulk powders and sieving characterized fractions of two qualities of orthoboric acid
1996
Drug Dev. Ind. Pharm. ISI Document Delivery No.: VN279 Times Cited: 1 Cited Reference Count: 22 Tromelin, A Habillon, S Andres, C Pourcelot, Y Chaillot, B; International audience; We have carried out a study of the particle size distribution and aqueous dissolution rate of two commercially available qualities of orthoboric acid, labeled ''crystal'' (ABC) and ''powder'' (ABP). In a previous work, we have shown that the two commercial qualities of orthoboric acid chosen as model compound (''powder'' and ''crystal'') are related to the same crystal network in spite of their different names. However, these two qualities have very different size particle distributions, as previously determined b…
Adaptogens in chemobrain (Part II): Effect of plant extracts on chemotherapy-induced cytotoxicity in neuroglia cells
2019
Abstract Background Cancer chemotherapy-induced cognitive impairments are apparently associated with harmful effects on physiological functions of brain cells. Adaptogens, are known to exhibit neuroprotective effects and to increase cognitive functions in clinical studies. In our previous study (Seo et al., 2018), we demonstrated that selected adaptogenic extracts significantly attenuate cytostatic-induced regulation of more than 100 genes involved in the activation of neuronal death and inhibiting neurogenesis. Neuroprotective and cytoprotective activities of adaptogens rise the question about their possible impact on cytostatic effects of a chemotherapeutic combination of 5-fluorouracil, …
Nierenfunktionspr�fung bei Ratten durch den Phenolsulfonphthalein-Test
1963
Ein Verfahren zur Durchfuhrung des Phenolsulfonphthalein-Testes an Ratten wird beschrieben. Die Tiere erhalten 5 mg Phenolsulfonphthalein/kg Korpergewicht als i.v. Injektion. 1 min und 10 min nach der Farbstoffgabe werden die Farbstoffkonzentrationen im Serum gemessen. Die Farbstoffretention nach 10 min ausgedruckt in Prozenten des 1 min-Wertes wird als Mas der Nierenfunktionsleistung angesehen.