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  • 1
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Ketotifen analysis ; Stability indicating analysis ; Aqueous and oil-based formulations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A simple and specific high-performance liquid chromatographic (HPLC) method for the analysis of ketotifen in aqueous solutions and silicon oil suspensions is described. The HPLC system is based on a reversed phase μBondapak C18 (30×0.39 cm) column with a mobile phase of phosphate buffer (0.001 M, pH 7.4):methanol: acetonitrile: trimethylamine (29.8:45:25:0.2, by volume) at a flow-rate of 1 mL min−1. The eluent was monitored by UV absorption at 299 nm. Silicon oil-based samples were extracted with HCl (0.05 M) using imipramine as internal standard. The recovery of ketotifen and imipramine was greater than 80%. The calibration curves for both assays were linear over the ranges examined, yielding correlation coefficients greater than 0.997. The assay was shown to be stability indicating by subjecting solutions of ketotifen in phosphate buffer to heat, oxidative stress and irradiation with ultraviolet light (254 and 369 nm)for up to 8 h. The methodology was also shown to be applicable for the analysis of ketotifen in simple aqueous based formulations, in suspension in silicon oil and for the analysis of samples derived fromin vitro skin transfer experiments.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1612-1112
    Keywords: Enantiospecific chromatography ; Sequential achiral-chiral liquid chromatography ; Sulindac enantiomers ; Chiral stationary phase ; Circular dichroism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The chromatographic resolution of the enantiomers of sulindac has been achieved using a Chiralpak AD CSP (10 μm, 250×4.6 mm) with a mobile phase of hexane: ethanol (85∶15 v/v) containing trifluoroacetic acid (0.05% v/v) at a flow rate of 1.0 mL min−1. Under these conditions the enantiomers eluted with separation and resolution factors of 1.43 and 2.46 respectively. Semipreparative isolation of the enantiomers and their characterization by circular dichroism spectroscopy and NMR, in the presence of a chiral shift reagent, indicated that the elution order was (−)-(S)- before (+)-(R)-sulindac. The enantiomeric composition of sulindac in urine following administration of the racemic drug to man was determined by sequential achiral-chiral chromatography. Achiral analysis was carried out using a Spherisorb S5 ODS2 stationary phase (5 μm, 250×4.6 mm) and a mobile phase of aqueous acetic acid (2% v/v; pH 3.5): acetonitrile: THF (50∶48∶2 by volume) at a flow rate of 1.0 mL min−1. The HPLC eluate containing sulindac (retention time 4.9 min) was collected and following workup, the enantiomeric composition of the drug was determined using the CSP. Over the 24 h collection period sulindac was excreted predominantly as theR-enantiomer, but the enantiomeric composition was found to vary markedly with time which is presumably associated with the complex metabolism of the drug.
    Type of Medium: Electronic Resource
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