[HPLC-ESI/MS analysis of stachydrine and its metabolites in rat urine].

AIM: To identify the main metabolites of stachydrine in rat. METHODS: The ionization, cleavage and chromatographic characteristics of stachydrine were studied by using high-performance liquid chromatography-electrospray ionization ion trap tandem mass spectrometry (HPLC-ESI/MS) for the first time. These characteristics of stachydrine were used as the basis for the analyses of metabolites in rat urine. The 0 - 24 h urine samples of rats after ig 25 mg x kg(-1) stachydrine were collected and purified by using C10 solid-phase extraction cartridge, and then analyzed by HPLC-ESI/MS to identify stachydrine and its metabolites. RESULTS: The parent drug (stachydrine), 6 phase I metabolites (N-demethyl, dehydrogenation, ring-oxidation) and 2 phase II metabolites (glycine conjugates of 2 ring-oxidation products) were identified existing in rat urine. CONCLUSION: The presented method was proved to be sensitive, rapid, high selective and specific for the identification of stachydrine and its metabolites in rat urine.

[Analysis of anisodine and its metabolites in rat plasma by liquid chromatography-tandem mass spectrometry].

AIM: To identify anisodine and its metabolites in rat plasma after ingestion of anisodine by combining liquid chromatography and tandem mass spectrometry (LC-MS(n)). METHODS: Plasma samples from rats after a single orally administration of 20 mg anisodine were added with methanol to precipitate protein. Then, it was analyzed by LC-MS(n). Identification and structural elucidation of the metabolites were performed by comparing their changes in molecular masses, retention-times and full scan MS(n) spectra with those of the parent drug and blank plasma. RESULTS: The results revealed that the parent drug and its four metabolites (norscopine, scopine, hydroxyanisodine, N-oxide anisodine) existed in rat plasma. CONCLUSION: This method is sensitive, rapid, simple, and it is suitable for the rapid identification of drug and its metabolits.

[Liquid chromatography-tandem electrospray ionization ion trap mass spectrometric assay for the metabolites of jatrorrhizine in rat urine].

AIM: To identify the main metabolites of jatrorrhizine in rat urine. METHODS: The rat urine samples were collected 0 - 72 h after ig 12 mg x kg(-1) jatrorrhizine, then the samples were purified through C18 solid-phase extraction cartridge. The purified samples were analyzed by combining liquid chromatography and tandem electrospray ionization ion trap mass spectrometry (LC-ESI/ITMS(n)). Identification and structural elucidation of the metabolites were performed by comparing the changes in molecular masses, retention-times and full scan MS(n) spectra with those of the parent drug. RESULTS: At least seven phase I metabolites (such as de-methyl, de-hydrogen and hydroxyl metabolites) and eleven phase II metabolites (such as glucuronide conjugates and methyl-conjugates) were identified in rat urine. CONCLUSION: The developed LC-ESI/ITMS(n) method is not only simple and rapid but also sensitive and specific for the identification of metabolites of jatrorrhizine in rat urine.

[Identification of hydroxylate metabolites of daidzein and its sulfate conjugates in rat urine by LC-ESI/MS(n)].

AIM: To identify the hydroxylate metabolites and its sulfate conjugates of daidzein in rat urine. METHODS: Urine samples from 0 - 24 h were collected after single ig dose of 500 mg x kg(-1) daidzein to each of six rats. The urine samples were purified by SPE column (SPE C18) and analyzed with liquid chromatographic-tandem electrospray ionization ion trap mass spectrometry (LC-ESI/MS(n)) for potential metabolites. RESULTS: Several new hydroxylate metabolites and its sulfate conjugates were found and identified in rat urine. CONCLUSION: LC-ESI/MS(n) is proved to be a simple, rapid, sensitive and specific technique for identification of the hydroxylate metabolites and its sulfate conjugates of daidzein in rat urine.

[Detection of anisodamine and its metabolites in rat feces by tandem mass spectrometry].

AIM: To establish a LC-MS(n) method for the identification of anisodamine and its metabolites in rat feces. METHODS: Feces samples were collected after single administration of 25 mg x kg(-1) anisodamine to rats, and dipped in water for 1 h. Samples were then extracted by ethyl acetate. The pretreated samples were separated on a reversed-phase C18 column using a mobile phase of methanol / 0.01% triethylamine (adjusted to pH 3.5 with formic acid) (60 : 40, v/v) and detected by LC-MS". Identification of the metabolites and elucidation of their structures were performed by comparing their changes in molecular masses (deltaM), retention-times and full scan MS(n) spectra with those of the parent drug and blank feces. RESULTS: The parent drug and its seven metabolites (6beta-hydroxytropine, nor-6beta-hydroxytropine, aponoranisodamine, apoanisodamine, noranisodamine and hydroxyanisodamine, tropic acid) were found in rat feces. CONCLUSION: This method is sensitive, rapid, simple, effective, and suitable for the rapid identification of drug and its metabolites in biologic samples.

[HPLC-MSn analysis of trigonelline and its metabolites in rat urine].

AIM: To establish a rapid and sensitive LC-MSn method for the identification of trigonelline and its main metabolites in rat urine. METHODS: After optimizing the detection conditions of LC-MSn chromatography and mass spectrometry using trigonelline, its ionization and cleavage in ESI-MS and ESI-MSn modes were summarized, then serving as the basis for the metabolite analysis of trigonelline in rat urine. The 0-48 h urine samples of rats were collected after iv 8 mg x kg(-1) trigonelline, then, the samples were purified through C18 solid-phase extraction cartridge. The purified samples were analyzed by LC-MSn. RESULTS: The structures of trigonelline metabolites were elucidated according to the changes of the molecular weights of the metabolites (deltaM) and their cleavage pattern in ESI-ITMSn. As a result, two phase I metabolites and the parent drug were identified existing in rat urine, and two phase II metabolites were identified. CONCLUSION: The LC-MSn method is rapid and high sensitive and specific, it is suitable for the identification of trigonelline and its metabolites in rat urine.

[Analysis of ephedrine and its metabolites in rat urine by HPLC-ESI-ITMSn].

AIM: To estabilish a rapid and sensitive LC-ESI-ITMSn method for the identification of ephedrine and its main metabolites in rat urine. METHODS: After optimizing the detection condition of LC-ESI-ITMSn chromatography and mass spectrometry by using a standard ephedrine, the ionization and cleavage rules of ephedrine in ESI-MS and ESI-MSn modes were summarized, and then serving as the basis for the metabolite analysis of ephedrine in rat urine. Rat urine samples of 0-48 h were collected after ig 10 mg x kg(-1) ephedrine, then the samples were purified through C18 solid-phase extraction cartridge. The purified samples were analyzed by LC-ESI-ITMSn. RESULTS: The structures of ephedrine metabolites were elucidated according to the changes of the molecular weights of the metabolites (deltaM) and their cleavage pattern in ESI-ITMSn. As a result, three phase I metabolites and the parent drug ephedrine were identified existing in rat urine, but no phase II metabolites were found. CONCLUSION: The LC-ESI-ITMSn method is rapid and highly sensitive and sepecific, it is suitable for the identification of ephedrine and its metabolites in rat urine.

[HPLC-electrospray ionization ion trap tandem mass spectrometry analysis of oxymatrine and its metabolites in rat urine].

AIM: To identify the main metabolites of oxymatrine (OMT) in rats. METHODS: To optimize the conditions of LC/ESI-ITMS' chromatograms and spectra by oxymatrine and matrine (MT), and summarize their ionization and cleavage rules in ESIMS, then serving as the basis for the metabolite analyses of oxymatrine in rats. To collect the 0-24 h urine samples of the rats after ip 40 mg x kg(-1) oxymatrine, the samples were enriched and purified through C18 solid-phase extraction cartridge. The purified samples were analyzed by LC/ESI-ITMS. The structures of OMT metabolites were identified according to their retention times and ESI-ITMSn rules. RESULTS: Six phase I metabolites and the parent drug OMT were found in the rat urine, and the main metabolite was MT. No phase II metabolites were found. CONCLUSION: The developed LC/ESI-ITMSn methods to identify the metabolites of oxymatrine in rats is not only simple and rapid but also sensitive and specific. This technology is one of the most efficient methods for the analysis of drug metabolites.