Showing papers by "King Faisal Specialist Hospital & Research Centre published in 2000"
TL;DR: The chemistry of these antibiotics, the effect of chromatographic conditions on enantioselectivity, the mechanism of resolution, the applications and limitations of the compounds, and detection in liquid chromatography and capillary electrophoresis with these antibiotics as the chiral selectors are described.
Abstract: The separation of enantiomers by liquid chromatography and capillary electrophoresis is important in pharmaceutical, environmental, and agricultural analysis. Of the different types of chiral selector used for enantiomer resolution the macrocyclic antibiotics are considered particularly effective. Only eight antibiotics, vancomycin, teicoplanin, thiostrepton, rifamycin B, kanamycin, streptomycin, fradiomycin, and ristocetin A have yet been used as chiral selectors for separation of the enantiomers of a variely of compounds by liquid chromatography and capillary electrophoresis. This review describes the chemistry of these antibiotics, the effect of chromatographic conditions on enantioselectivity, the mechanism of resolution, the applications and limitations of the compounds, and detection in liquid chromatography and capillary electrophoresis with these antibiotics as the chiral selectors.
95 citations
TL;DR: The chiral resolution of seven aromatase inhibitors (Ia, Ib, Ic, and Id) and three tetrazole derivatives (IIa, IIb, and IIc) was achieved on Chiral Cel OJ-R, Chiralcel OD-RH, and Chiralpak AD-RH chiral stationary phases.
71 citations
TL;DR: In this article, the authors present the instrumentation involved in their design, including light detection and flow injection analysis system used for the analysis of inorganic and organic compounds from gaseous samples and solutions indicate that these sensors are used with good reproducibility and selectivity of the analytes at low concentration level.
Abstract: Chemiluminescence sensors are important tools in analytical chemistry due to their high sensitivity selectivity. This review presents the instrumentation involved in their design, including light detection and flow injection analysis system used. Various applications for the analysis of inorganic and organic compounds from gaseous samples and solutions indicate that these sensors are used with good reproducibility and selectivity of the analytes at low concentration level.
52 citations
TL;DR: It was found that some reducing agents give chemiluminescence with luminol in the presence of hexacyanoferrate (III) in an alkaline solution, which is a new type of chemiluminometric reaction for the enzymatic determination of ascorbic acid.
Abstract: A simple, selective and rapid method for determination of ascorbic acid from fruit juices was developed by combining a flow injection analysis (FIA) system with a chemiluminometric detector and a reactor with L-ascorbate oxidase immobilized on controlled pore glass. It was found that some reducing agents (eg ascorbic acid and mercaptoacetic acid) give chemiluminescence with luminol in the presence of hexacyanoferrate (III) in an alkaline solution. We used this new type of chemiluminescent reaction for the enzymatic determination of ascorbic acid. The background substraction method was used in order to avoid interference during ascorbic acid determination. Accordingly, two chemiluminometric signals were registered for each determination, one signal corresponding to the sample that passed through the enzymatic reactor that decomposed the ascorbic acid completely, and the second signal corresponding to the sample that does not pass through the reactor. The difference between the two signals corresponds to ascorbic acid from the sample. The linear range of the method was 10-1000 micromol/L of ascorbic acid and the detection limit was 5 micromol/L The throughput was four samples/h and RSD 3.13% (n = 10). This method was applied for determination of ascorbic in fruit juices. The results were compared with those found by the reference method, based on titrimetric determination with 2,6-dichlorophenolindophenol, and the concordance was excellent.
39 citations
TL;DR: In this paper, an ion selective PVC membrane electrode for determination of propranolol is developed, which exhibits excellent potential respon se properties, showing a Nernstian response in the concentration of 3.0 〈 10-6~ 2.6 mV with the slope of 54.7 mV per decade.
Abstract: A novel ion selective PVC membrane electrode for determination of propranolol is developed. Silicotungstic acid is used as the counter ion and diisononyl phthalate (DNP) used as the plastizer. The electrode exhibits excellent potential respon se properties, showing a Nernstian response in the concentration of 3.0 〈 10-6~ 2.6 〈 10-2 M with the slope of 54.7 mV per decade, shorter conditioning time (~ 3 h), fast response time (40 s), a lower limit of detection (1.0 〈 10-7 M). The electrode is success- fully used for the analysis of propranolol in pharmaceutical formulation with the recoveries of 99.2 ~ 102.6 %, by using a direct potentiometric method and which does not require tedious sample preparation.
29 citations
TL;DR: In this article, the enantiomeric resolution of aminoglutethimide as dansyl derivatives was investigated on reversed phase TLC using a mobile phase consisting of a β-cyclodextrin solution (0.05 M saturated with urea), or 15% (carboxymethyl-β-cyclodesxtrin) solution with methanol (65:35v/v).
Abstract: Racemic aminoglutethimide and acetylaminoglutethimide were resolved on a fluorescent Silica gel 60A TLC plate using 30% hydroxy trimethylpropylammonium-β-cyclodextrin with methanol (50:50v/v) as the mobile phase. Also, the resolution of the enantiomers of aminoglutethimide as dansyl derivatives were investigated on reversed phase TLC using a mobile phase consisting of a β-cyclodextrin solution (0.05 M saturated with urea), or 15% (carboxymethyl-β-cyclodextrin) solution with methanol (65:35v/v). Enantiomeric resolution was found to be highly dependent on mobile phase composition. The effect of the type and amount of organic modifier as well as the concentration of β-CD derivative, and the pH of the mobile phase on resolution were studied. Three types of maltodextrins failed to show resolution for any of the racemic compounds studied.
8 citations
TL;DR: A case of a bladder-wall abscess in a patient with myelodysplasia and a neurogenic bladder is reported, who had recurrent urinary tract infections and was being managed by clean intermittent catheterisation.
Abstract: We report a case of a bladder-wall abscess in a patient with myelodysplasia and a neurogenic bladder. The aetiology of the abscess was obscure, but the patient had recurrent urinary tract infections and was being managed by clean intermittent catheterisation.
7 citations
TL;DR: Recently, Wetterberg published a review on the clinical applications of melatonin in humans and its role on traits such as sleep, Circadian rhythm, surgical stress, and anesthesia.
Abstract: Since its discovery nearly forty years ago, melatonin (N-acetyl-5-methoxy tryptamine) has been widely investigated with regard to the factors that control its synthesis and in reference to its endocrine consequences. The pineal hormone melatonin is involved in the transduction of photoperiodic information which regulates a variety of physiological functions, including reproduction and body weight. Recently, Wetterberg published a review on the clinical applications of melatonin in humans and its role on traits such as sleep, Circadian rhythm, surgical stress, and anesthesia.