A selective precolumn derivatization liquid chromatography–tandem mass spectrometric (LC–MS/MS) method for the determination of glucosamine in human plasma and urine has been developed and validated. Glucosamine was...A selective precolumn derivatization liquid chromatography–tandem mass spectrometric (LC–MS/MS) method for the determination of glucosamine in human plasma and urine has been developed and validated. Glucosamine was derivatized by o-phthalaldehyde/3-mercaptopropionic acid. Chromatographic separation was performed on a Phenomenex ODS column (150 mm 4.6 mm, 5 mm) using linear gradient elution by a mobile phase consisting of methanol (A), and an aqueous solution containing 0.2% ammonium acetate and 0.1% formic acid (B) at a flow rate of 1 mL/min. Tolterodine tartrate was used as the internal standard (IS). With protein precipitation by acetonitrile and then the simple one-step derivatization, a sensitive bio-assay was achieved with the lower limit of quantitation (LLOQ) as low as 12 ng/mL for plasma. The standard addition calibration curves suitable for clinical sample analysis showed good linearity over the range of 0.012–8.27 mg/mL in plasma and 1.80–84.1 mg/mL in urine. The fully validated method has been successfully applied to a pharmacokinetic study of compound glucosamine sulfate dispersible tablets in health Chinese volunteers receiving single oral doses at 500, 1000 and 1500 mg of glucosamine sulfate, as well as multiple oral doses of 500 mg t.i.d. for 7 consecutive days.展开更多
Taurine is concentrated in glial cells in the hypothalamus and released in an osmo-dependent manner through volume-sensitive anion channels. Released tanrine acts on glycine receptors on vasopressin neurons to control...Taurine is concentrated in glial cells in the hypothalamus and released in an osmo-dependent manner through volume-sensitive anion channels. Released tanrine acts on glycine receptors on vasopressin neurons to control vasopressin secretion. Water channel AQP4 is abundant in astrocytes in osmosensory areas such as the supraoptic nucleus of hypothalamus. An HPLC-based method was established to quantify taurine release from isolated hypothalamus tissues in wildtype and AQP4 knockout mice. Under the basal condition, there was no difference in taurine release from AQP4^＋/＋ and AQP4^-/- hypothalamuses. Taurine release from AQP4^-/- hypothalamus under hypoosmotic stimulation was significantly lower than that from AQP4^＋/＋ mice. AQP4 expression in the glial cells of the hypothalamus may play an important role in osmoregulation oftaurine release and subsequent vasopressin secretion.展开更多
A convenient derivatization method of amino acids with 1-fluoro-2,4-dinitrobezene as reaction reagent and a separation system were described. The derivative amino acids were separated on a specific chemically bonded p...A convenient derivatization method of amino acids with 1-fluoro-2,4-dinitrobezene as reaction reagent and a separation system were described. The derivative amino acids were separated on a specific chemically bonded phase column with a simple linear gradient elution consisting of aqueous buffer and methanol. The eluate was detected by common ultraviolet absorption detector at 360 nm. The detection limits of amino acids were as low as 10 picomole. This method has been successfully applied to assay amino acid injection liquor used in hospital. It has good reproducibility and precision. The procedures avoid the requirements of particular derivative equipment and analyzer employed in conventional amino acid analysis.展开更多
文摘A selective precolumn derivatization liquid chromatography–tandem mass spectrometric (LC–MS/MS) method for the determination of glucosamine in human plasma and urine has been developed and validated. Glucosamine was derivatized by o-phthalaldehyde/3-mercaptopropionic acid. Chromatographic separation was performed on a Phenomenex ODS column (150 mm 4.6 mm, 5 mm) using linear gradient elution by a mobile phase consisting of methanol (A), and an aqueous solution containing 0.2% ammonium acetate and 0.1% formic acid (B) at a flow rate of 1 mL/min. Tolterodine tartrate was used as the internal standard (IS). With protein precipitation by acetonitrile and then the simple one-step derivatization, a sensitive bio-assay was achieved with the lower limit of quantitation (LLOQ) as low as 12 ng/mL for plasma. The standard addition calibration curves suitable for clinical sample analysis showed good linearity over the range of 0.012–8.27 mg/mL in plasma and 1.80–84.1 mg/mL in urine. The fully validated method has been successfully applied to a pharmacokinetic study of compound glucosamine sulfate dispersible tablets in health Chinese volunteers receiving single oral doses at 500, 1000 and 1500 mg of glucosamine sulfate, as well as multiple oral doses of 500 mg t.i.d. for 7 consecutive days.
基金Supported by the National Natural Science Foundation of China(Nos.30670477 and 30770493)
文摘Taurine is concentrated in glial cells in the hypothalamus and released in an osmo-dependent manner through volume-sensitive anion channels. Released tanrine acts on glycine receptors on vasopressin neurons to control vasopressin secretion. Water channel AQP4 is abundant in astrocytes in osmosensory areas such as the supraoptic nucleus of hypothalamus. An HPLC-based method was established to quantify taurine release from isolated hypothalamus tissues in wildtype and AQP4 knockout mice. Under the basal condition, there was no difference in taurine release from AQP4^＋/＋ and AQP4^-/- hypothalamuses. Taurine release from AQP4^-/- hypothalamus under hypoosmotic stimulation was significantly lower than that from AQP4^＋/＋ mice. AQP4 expression in the glial cells of the hypothalamus may play an important role in osmoregulation oftaurine release and subsequent vasopressin secretion.
基金supported by the National Natural Science Foundation of China.
文摘A convenient derivatization method of amino acids with 1-fluoro-2,4-dinitrobezene as reaction reagent and a separation system were described. The derivative amino acids were separated on a specific chemically bonded phase column with a simple linear gradient elution consisting of aqueous buffer and methanol. The eluate was detected by common ultraviolet absorption detector at 360 nm. The detection limits of amino acids were as low as 10 picomole. This method has been successfully applied to assay amino acid injection liquor used in hospital. It has good reproducibility and precision. The procedures avoid the requirements of particular derivative equipment and analyzer employed in conventional amino acid analysis.
