Study on the extraction recovery of ginsenoside Re in plasma by different solid-phase cartridges / 中国中药杂志

<p><b>OBJECTIVE</b>To optimize the solid-phase extraction method by comparison of the extraction recovery of ginsenoside Re plasma samples.</p><p><b>METHOD</b>After extracted by different solid-phase cartridges with water, acetonitrile, and different content methanol elution, the plasma samples were analyzed on an Zorbax SB-C18 column with acetonitrile-water gradient elution. From the recovery achieved, the best solid phase cartridge was found.</p><p><b>RESULT</b>This method consists of using 40% methanol as the wash solvent, and 80% methanol for the elution. Among the three kinds of solid-phase being tested, Waters Oasis HLB cartridge was found to be the best one.</p><p><b>CONCLUSION</b>The average extraction recovery of the Waters Oasis HLB cartridges was between 103%-113%, it can be used in the analysis of ginsenoside Re in plasma samples.</p>

Pharmacokinetics of oxymatrine and its metabolite in beagle dogs by LC-MS / 中国中药杂志

<p><b>OBJECTIVE</b>To establish LC-MS method in the determination of oxymatrine and its metabolite in plasma and investigate their pharmacokinetics in beagle dogs.</p><p><b>METHOD</b>Lichrospher C18 column (4.6 mm x 250 mm, 5 microm) was used as the analytical column maintained at 25 degrees C. The mobile phase consisted of 10 mmol x L(-1) CH3COONH4 and CH3OH (25:75). Flow rate was 1 mL x min(-1). Electrospray ionization (ESI) was carried out. The ESI ion source was set in positive ion polasity mode. The selective ion monitoring (SIM) was set at m/z 265.1 and 249.2.</p><p><b>RESULT</b>The linearity ranged from 2 to 5000 ng x mL(-1) (r = 0.9991). The detection of oxymatrine and its metabolite were 0.6 and 0.3 ng x mL(-1). The RSD(%) within day and between day was less than 4.7%. The recovery of this method was more than 96.5%. The disposition was conformed to a two-compartment model. The T(1/2), Tmax, Cmax, MRT, AUC(0-->24 h) of oxymatrine were (5.5+/-1.58) h, (1.0+/-0.30) h, (2418.3 +/-970.78) ng x mL(-1), (3.2+/-0.64) h, (5797.4+/-908.16) ng x mL(-1) x h accordingly. The corresponding T(1/2), Tmax, Cmax, MRT, AUC(0-->24 h) of matrine were (9.8+/-2.77) h, (1.9+/-1.09) h, (1532.4+/-494.86) ng x mL(-1), (4.4+/-1.97) h, (5530.5+/-1042.65) ng x mL(-1) x h.</p><p><b>CONCLUSION</b>This assay was highly sensitive, rapid, simple and specific enough for determining concentrations of oxymatrine and its metabolite matrine in plasma of beagle dog.</p>

Analysis of impurity in caderofloxacin / 药学学报

<p><b>AIM</b>To analyse the main impurity of caderofloxacin.</p><p><b>METHODS</b>The impurity of caderofloxacin was analysed and determinated by RP-HPLC/ESI/MS with a Zorbax SB-C18 (150 mm x 4.6 mm ID, 5 microns) column. The mobile phase was acetonitrile-0.5% acetic acid solution (17:83). A compound was synthesized: 1-cyclopropyl-8-(difluoromethoxy)-6-fluoro-1, 4-dihydro-7-(1-piperazinyl)-4-oxo-3-quinoline carboxylic acid (DMCA). Its HPLC chromatogram, UV and MS spectrum were compared with those of the impurity in caderofloxacin.</p><p><b>RESULTS</b>The molecular weight of the impurity was 14 less than that of caderofloxacin. It means the impurity was a CH2-group less than caderoflixacin. The tR, UV and MS of DMCA were the same as those of the impurity in caderofloxacin.</p><p><b>CONCLUSION</b>Based on the tR (HPLC), UV and MS, the impurity of caderofloxacin is confirmed as DMCA.</p>

Determination of first-order structure of somatostatin by electrospray ionization mass spectrometry / 药学学报

<p><b>AIM</b>To determine the molecular weight and first-order structure of somatostatin.</p><p><b>METHODS</b>The molecular weight of somatostatin was determined by electrospray ionization mass spectrometry. Somatostatin was deoxidized by 2-mercaptoethanol. A series of typical fragment ions of deoxidized product were obtained by insource collision-induced dissociation (CID).</p><p><b>RESULTS</b>The m/z of quasi-molecular ion [M + H]+ of somatostatin was 1,637.8 and [M + Na]+ was 1,659.5. The m/z of double-charge ion [M + 2H]2+ was 819.5 and [M + H + Na]2+ was 830.3. It showed that the molecular weight of somatostatin was 1,636.7. The y and b series of fragment ions of deoxidized product were obtained by adjusting the fragmentor voltage. It was determined that the first-order structure of deoxidized product of somatostatin was A-G-C-K-N-F-F-W-K-T-F-T-S-C.</p><p><b>CONCLUSION</b>The molecular weight and first-order structure of somatostatin were confirmed.</p>

Analysis of the response factors of different quinolones detected by evaporative light-scattering detector / 药学学报

<p><b>AIM</b>To analyze the response factors of different quinolone antibiotics detected by evaporative light-scattering detector (ELSD).</p><p><b>METHODS</b>The response factors of five different quinolones (enoxacin, levofloxacin, ciprofloxacin, lomefloxacin and gatifloxacin) detected by ELSD were determined by using a YMC-Pack ODS-AM cloumn (150 mm x 4.6 mm ID, 5 microns) as analytical column and 0.5% triethylamine (adjusting pH 2.5 with trifluoroacetic acid)-acetonitrile (48:12) as mobile phase at a flow rate of 0.6 mL.min-1, the temperature of the drift tube was set at 117 degrees C, and the flow of carrier gas at 3.0 L.min-1. Detector responses (A) and the amount of injection of each substance (m) were fitted to the logarithmic regression: log A = b log m + log a.</p><p><b>RESULTS</b>The linear regression equation obtained were: enoxacin: Y = 1.0799X + 2.7611, r2 = 0.9996; levofloxacin: Y = 1.0913X + 2.7235, r2 = 0.9997; ciprofloxacin: Y = 1.0828X + 2.7523, r2 = 0.9994; lomefloxacin: Y = 1.0891X + 2.7391, r2 = 0.9993; gatifloxacin: Y = 1.0878X + 2.7392, r2 = 0.9995. The differences between them were negligible.</p><p><b>CONCLUSION</b>Different quinolones can give the same responses with ELSD detection. So, the HPLC-ELSD methods can be applied to the determination of new substances by using another substance as reference.</p>

Study on the fingerprints of the alkaloids in Sophora flavescens / 中国中药杂志

<p><b>OBJECTIVE</b>To establish a method for HPLC fingerprint determination of the alkaloids in S. flavescens.</p><p><b>METHOD</b>RP-HPLC, linear gradient elution, LC/MS, etc. were used to determine the fingerprint and identify the main peaks in the HPLC fingerprint.</p><p><b>RESULT</b>A satisfactory method for HPLC fingerprint determination of the alkaloids in S. flavescens. was established, and 5 peaks in the HPLC fingerprint were identified.</p><p><b>CONCLUSION</b>The perfect fingerprint can be obtained and the method can be used for quality control of S. flavescens.</p>

Study on HPLC fingerprint of the triterpene acids in Poria cocos / 中国中药杂志

<p><b>OBJECTIVE</b>To establish a method for HPLC fingerprint determination of the triterpene acids in Poria cocos.</p><p><b>METHOD</b>RP-HPLC, linear gradient elution and LC/MS, etc. were used to optimize the fingerprint determination method, and identify the main peaks in the HPLC fingerprint.</p><p><b>RESULT</b>A preferable method for HPLC fingerprint determination of the triterpene acids in P. cocos was established, and 9 peaks in the HPLC fingerprint were identified.</p><p><b>CONCLUSION</b>A general acquaintance of the triterpene acids in P. cocos can be obtained by using the preferable HPLC fingerprint determination method, which is useful for quality evaluation of the crud drug of P. cocos.</p>

Impurity analysis and their structure determination of gatifloxacin / 药学学报

<p><b>AIM</b>To analyse the impurities of gatifloxacin.</p><p><b>METHODS</b>The impurity of gatifloxacin were analysized and determinated by RP-HPLC/electrospray ionization mass spectrometry with a Zorbax SB-C18(4.6 mm x 150 mm ID, 5 microns). The mobile phase was 3% acetic acid/acetonitrile-3% acetic acid/water (15:85). The two compounds were synthesized: 1-cyclopropyl-6-fluoro-1, 4-dihydro-8-methoxy-7-(1-piperazinyl)-4-oxo-3-quinolinecarboxylic acid (DMP) and 1-cyclopropyl-6-fluoro-1, 4-dihydro-8-hydro-7-(3-methy-1-piperazinyl)-4-oxo-3-quinolinecarboxylic acid (DMO). Their liquid chromatogram, UV, MS were compared with those of the impurity of gatifloxacin.</p><p><b>RESULTS</b>The mass of the impurity was 14 less than that of gatifloxacin. It means the impurity was CH2 less than gatifloxacin. The tR (HPLC), UV and MS of DMP were the same as those of the impurity of gatifloxacin.</p><p><b>CONCLUSION</b>Based on the tR (HPLC), UV and MS, the impurity of gatifloxacin is confirmed as DMP.</p>

Determination of cyclovirobuxine D by RP-HPLC with precolumn fluorescence derivatization / 药学学报

<p><b>AIM</b>To establish a RP-HPLC method for determination of cyclovirobuxine D.</p><p><b>METHODS</b>Cyclovirobuxine D reacted with a derivative reagent 1-naphthyl isocyanate in chloroform to form fluorescence derivatives, stopped the reaction by adding the mobile phase and then directly injected the solution into the chromatograph to seperate it by RP-HPLC. The analysis was carried out on C18 column, the mobile phase is methanol-water (85:15), the excitation wavelength was set at 305 nm, emission at wavelength 385 nm, and the flow rate was 1 mL.min-1. The effect of several factors including the reaction medium, temperature, time and amount of 1-naphthyl isocyanate on the yield of the derivatization was also investigated systematically.</p><p><b>RESULTS</b>A simple and rapid RP-HPLC method for the simultaneous isolation and analysis of cyclovirobuxine D and its related substances was developed, and the absence of interference between the derivative peak responses of cyclovirobuxine D and its related substances were verified by UV diode array detecter and MS. The linearity was obtained from 0.75 microgram.mL-1 to 2.5 micrograms.mL-1 of cyclovirobuxine D derivatives with a correlation coefficient of 0.9991. The detection limit of cyclovirobuxine D derivative was 1 ng.mL-1, the repeatability of derivatization was good with relative standard derivation no more than 1.2% and derivative was stable within 48 h. The method described conforms to the validation of China Pharmacopiea compendial methods used for pharmaceutical products in general.</p><p><b>CONCLUSION</b>The established method is proved to be reliable quantitative method for the quality control of cyclovirobuxine D.</p>