HPLC-MS/MS Determination of Oleandrin and Adynerin in Blood with Solid Phase Supported Liquid-Liquid Extraction

[Objectives]To optimize the determination method of oleandrin and adynerin in blood. [Methods]High performance liquid chromatography-mass spectrometry( HPLC-MS/MS) was applied to determine oleandrin and adynerin in blood. The blood sample was dispersed and fixed on a solid phase supported liquid-liquid extraction column and eluted with ethyl acetate. The resulting eluent was used for chromatographic separation with Kinetex C_(18) column as the separation column and gradient elution was performed using 10 mmol/L ammonium formate solution containing 0. 1%( volume fraction) formic acid and acetonitrile as the mobile phase. In the tandem mass spectrometry analysis,the detection was carried out using the electrospray positive ion source multiple reaction monitoring mode. [Results] The mass concentration of oleandrin and adynerin showed linear relationship in the range of 2-100 μg/L. The limit of detection( 3 S/N) of the method was 0. 5 μg/L.A blank sample was used as the substrate for the spike recovery test. The recovery rate was in the range of 90. 0%-98. 0%,and the relative standard deviation( RSD) of the measured values( n = 6) was in the range of 2. 1%-7. 3%. [Conclusions]The method established in this experiment has the benefits of simple pretreatment,good recovery,high sensitivity and strong specificity,and is expected to provide an ideal method for the determination of such drugs in blood.

Determination of risperidone in human plasma by HPLC-MS/MS and its application to a pharmacokinetic study in Chinese volunteers

This study presents a rapid, specific and sensitive liquid chromatography/tandem mass spectrometry (LC-MS/MS) assay for determination of risperidone (RIS) in human serum using paroxetine as an internal standard (IS). An Alltima-C18 column (2.1 mm×100 mm, 3 μm) and a mobile phase consisting of 0.1% formic acid-acetonitrile (40:60, v/v) were used for separation. The analysis was performed by selected reaction monitoring (SRM) method, and the peak area of the m/z 411.3→191.1 transition for RIS was measured versus that of the m/z 330.1→192.1 transition for IS to generate the standard curves. The assay linearity of RIS was confirmed over the range 0.25～50.00 ng/ml and the limit of quantitation was 0.05 ng/ml. The linear range corresponds well with the serum concentrations of the analytes obtained in clinical pharmacokinetic studies. Intraday and interday relative standard deviations were 1.85%～9.09% and 1.56%～4.38%, respectively. The recovery of RIS from serum was in the range of 70.20%～84.50%. The method was successfully applied to investigate the bioequivalence between two kinds of tablets (test versus reference products) in 18 healthy male Chinese volunteers. The result suggests that two formulations are bioequivalent.

Mass Spectrometric Structure Elucidation of the Trivalent and Pentavalent Nitrogen Contaminants of Pholcodine in the Cough Relief Medical Form Tuxidrin

In the paper “Supercritical Fluid Chromatography-Mass Spectrometry (SFC-MS) and MALDI-TOF-MS of Heterocyclic Compounds with Trivalent and Pentavalent Nitrogen in Cough Relief Medical Forms Tuxi and Cosylan” [1], the presence of morphine and other degradation products of pholcodine in cough relief medical forms of Tuxi are discussed. Tuxiis recalled from the Norwegian market by Weifa pharmaceutical company, and hence it no longer presents problems to users and health authorities there;however, the medical form Tuxidrin, which contains a significant amount of pholcodine as the active pharmacological ingredient, is still marketed. In the present paper, Tuxidrin is analyzed to determine the presence of degradation products of pholcodine. The degradation of pholcodine to morphine has been discussed previously as a factor in the development of addiction to narcotics in young persons. The structures of the contaminants in Tuxidrin, such as oxides of pholcodine, are elucidated in the present paper. The toxicity and pharmacology of oxides of alkaloids have generally not been well studied, and very little is known about the toxicity and pharmacology of the degradation (oxidation) products of pholcodine: the N-oxide and the N, N'-dioxide of pholcodine. According to Brondz and Brondz[1], the N-oxide and possibly also the N, N'-dioxide are less toxic than the original alkaloids and possess greater pharmacological activity, and hence they may be a source of useful new semisynthetic drugs. The question of possible addiction to pholcodine oxides has not been studied, and the potential of these substances to provoke allergies is unclear. The recall of Tuxi from the Norwegian marketis mainly based on the fact that pholcodine causes significantly increased levels of IgE antibodies in sensitized patients. Tuxidrin contains pholcodine and has the same negative effect as Tuxi, namely provoking allergies or even anaphylactic shock. From this point of view, Tuxidrin has no advantage over Tuxi. These two medical forms only differ in one respect: Tuxidrin requires a prescription (prescription duty medicine), but Tuxi doesnot (prescription free medicine). This aspect is also discussed in the present paper.

Simultaneous determination of 14β-lactam antibiotics in cosmetic products by liquid chromatography tandem mass spectrometry method

In this study,a simple and rapid high-performance liquid chromatography-tandem mass spectrometry（HPLC-MS/MS） method was established and validated to determine the 14β-lactam antibiotics in cosmetic products,including 1（ceftazidime）,2（cefaclor）, 3（cefdinir）,4（ampicillin）,5（cefalexin）,6（ceftezole）,7（cefotaxim）,8（cefradine）,9（cefuroxime）,10（cephazoline）,11 （cefathiamidine）,12（cefoperazone）,13（cafalotin）,14（piperacillin）.

Simultaneous determination of seven prohibited substances in cosmetic products by liquid chromatography-tandem mass spectrometry

In this paper,we developed and validated a simple,sensitive,and selective high-performance liquid chromatography-tandem mass spectrometry（HPLC-MS/MS） method to identify and measure the following prohibited substances that may be found in cosmetic products：minoxidil,hydrocortisone, spironolactone,estrone,canrenone,triamcinolone acetonide and progesterone.Chromatographic separation was performed on a Waters Symmetry C18（100 mm×2.1 mm,3.5μm particle size） with a gradient elution system composed of 0.2%（v/v） formic acid aqueous solution and methanol containing 0.2%（v/v） formic acid at a flow rate of 0.3 mL/min.The substances were detected using a triple quadrupole mass spectrometer in the multiple reaction monitoring mode with an electrospray ionization source.All of the calibration curves showed good linearity（r 〉 0.999） within the tested concentration ranges.The limit of detection was 〈25 pg.The relative standard deviations for intraday precision for each of the prohibited substances were 〈3.5%at two concentration levels（2μg/g,10μg/g）. The relative recovery rate for each of the prohibited substances ranged from 91.8%to 111%at three concentration levels（0.1μg/g,2μg/g,10μg/g）,including the limit of quantification.In conclusion,we have developed and validated a method that can identify seven prohibited substances in cosmetic products.

Association of 2-methoxyestradiol levels with the occurrence and development of endometrial cancer in humans

Objective The aim of the study was to determine the association of urinary levels of estradiol(E_(2))and 2-methoxyestradiol(2-MeOE_(2))with the occurrence and development of endometrial cancer.Methods In this case-control study,24-h urine specimens were collected from 28 postmenopausal patients with endometrial cancer and 28 postmenopausal healthy female controls.The concentration of 2-MeOE_(2) was determined using liquid chromatography-mass spectrometry with hollow fiber liquid-phase microextraction.The concentration of E_(2) was determined using an enzyme-linked immunosorbent assay.Results Estrogen levels were different between the patients with endometrial cancer and controls.The relative quantity of E_(2) in the case group was higher than that in the control group(P<0.05),whereas that of 2-MeOE_(2) was lower in the case group than that in the control group(P<0.05).The ratio of E_(2)-to-2-MeOE_(2) in the case group was significantly higher than that in the control group(P<0.05).Conclusion The results of this study indicate an imbalance of estrogen metabolites in endometrial carcinogenesis.Reduced 2-MeOE_(2) levels and elevated E_(2)-to-2-MeOE_(2) ratio may be used as potential biomarkers for the risk assessment of estrogen-induced endometrial cancer.

Evaluation of the hepatoprotective and antioxidant activities of Rubus parvifolius L.

The hepatoprotective and antioxidant activities of the n-butanol extract of Rubus parvifolius L. （RPL）, a widely used medicinal plant, were evaluated. Results demonstrated that RPL extract possessed pronounced hepatoprotective effects against carbon tetrachloride （CCI4）-induced hepatic injury in mice, which was at least partially attributed to its strong antioxidant capacity. Treatment with RPL extract markedly attenuated the increases in serum alanine ami- notransferase （ALT） and aspartate aminotransferase （AST） levels caused by CCI4 intoxication. It also significantly prevented the decrease in superoxide dismutase （SOD） activity and the increase in malondialdehyde （MDA） content of liver tissue. Meanwhile, histopathological changes of hepatic damage were also remarkably ameliorated. Phytochemical analysis based on high-performance liquid chromatography/tandem mass spectrometry （HPLC-MS/MS） revealed the presence of various phenolic compounds, including caffeic acid conjugates, ellagic acid glycosides, and flavonol glycosides, which might be responsible for the hepatoprotective and antioxidant activities of RPL.