Biomedical Chromatography

Zheng, Jian; Shao, Changmin; Fan, Bo; Jing, Lijia; Li, Siyang; Yan, Xiufeng; Wang, Yang

doi: 10.1002/bmc.4336pmid: 30003562

In the present study, a 10‐position modified of camptothecin, 10‐propionyloxy camptothecin (PCPT) was esterified from 10‐hydroxcamptothecin (HCPT), which could metabolize to HCPT in vivo. PCPT displayed a relatively stronger antitumor activity in vitro and in vivo. Thereafter a simple, sensitive and rapid HPLC method coupled with a fluorescence detector was developed and validated for the assay of PCPT and its active metabolite HCPT in rat plasma. The method was validated for accuracy, precision, linearity, selectivity and recovery. The validated method was successfully applied to the pharmacokinetic study of PCPT in rats after intravenous administration. The results showed that PCPT could be mainly converted to HCPT in plasma with the AUC0‐∞ value of 3.69 ± 4.44 and 311.16 ± 188.81 ng h/mL for PCPT and HCPT, respectively.

Hancu, Gabriel; Budău, Monica; Muntean, Daniela Lucia; Gagyi, Laszlo; Rusu, Aura

doi: 10.1002/bmc.4335pmid: 30006987

Chirality is a key subject in modern drug research as well as in the pharmaceutical industry and drug development. Almost all second‐generation modern antidepressants are chiral substances; however in therapy some are used as racemic mixtures while others are used as pure enantiomers. The development of enantioseparation methods of chiral antidepressants and their metabolites is one of the keys in understanding their enantioselective drug action. For this purpose, efficient and reliable analytical methods are needed, and capillary electrophoresis has proved to be an interesting and advantageous alternative to the more frequently used chromatographic techniques. In this review electrodriven methods available for the chiral discrimination of selective serotonin reuptake inhibitors (fluoxetine, citalopram, sertraline) and selective serotonin and norepinephrine reuptake inhibitors (venlafaxine, duloxetine) are presented and discussed.

Huang, Dan; Jiang, Qing‐Song; Yang, Jun‐Qing; Cui, Ting; Wang, Nian‐Ru; Du, Ting‐Ting; Jiang, Xin‐Hui

doi: 10.1002/bmc.4338pmid: 30003560

The determination of amino acids and monoamine with actions like neurotransmitters or modulators has become increasingly important for studying the relationship between the dysfunction of neurotransmitters and the pathogenesis of diabetic encephalopathy. Here, a high‐performance liquid chromatography with fluorescence detection method was developed to simultaneously determine nine monoamines and amino acids including three excitatory neurotransmitters (aspartate, glutamate, and serotonin), four inhibitory neurotransmitters (glycine, γ‐aminobutyric acid, taurine, dopamine), a precursor of 5‐HT (tryptophan) and methionine using homoserine as the internal standard. The separation was performed on a BDS column with methanol‐buffer solution of 35 mmol/L sodium acetate and 5 mmol/L citric acid (pH 6.0) using a simple gradient elution. Several parameters including specificity, precision, and recovery were validated after optimization of the analytical conditions. The developed method was successfully applied to determine the cortex and the hippocampus samples from Sprague–Dawley rats. Our results showed that various neurotransmitters involved in diabetes mellitus may tend to be differentially modulated and present a different alteration tendency at different time course, which might be associated with the duration of diabetes mellitus.

Zheng, Weijia; Choi, Jeong‐Min; Kim, Seong‐Kwan; Shim, Jae‐Han; Kang, Young‐Sun; Abd El‐Aty, A. M.; Hacımüftüoğlu, Ahmet; Shin, Ho‐Chul

doi: 10.1002/bmc.4339pmid: 30001571

A reliable and highly sensitive detection method based on liquid chromatography coupled with triple quadrupole electrospray tandem mass spectrometry (LC‐MS/MS) analysis has been developed for determination and quantification of halquinol, including 5,7‐dichloroquinolin‐8‐ol and 5‐chloroquinolin‐8‐ol. The target analytes were extracted from porcine muscle, egg, milk, eel, flatfish and shrimp using a mixture of acetonitrile and ethyl acetate followed by liquid–liquid purification with n‐hexane. The analytes were separated on an Agilent Eclipse XDB‐C18 reversed‐phase analytical column using 0.05% formic acid in distilled water and acetonitrile as mobile phases. Good linearity from six‐point matrix‐matched calibration was obtained with correlation coefficients (R2) ≥ 0.9904. Recoveries from three spiking levels (5, 10 and 20 μg/kg) ranged between 70.6 and 101.7% in various matrices with relative standard deviations ≤8.6%. Samples acquired from markets located in Seoul, Republic of Korea, tested negative for the target analytes. In conclusion, the proposed method is versatile and precise for the routine detection of halquinol residual levels in animal‐derived food products intended for human consumption.

Li, Ying; Wang, Lifang; Yang, Xianzhao; Ye, Yongan; Tu, Pengfei; Wang, Jinling

doi: 10.1002/bmc.4337pmid: 30003566

Tubeimoside I (Tub) is a triterpenoid saponin isolated from Bolbostemma paniculatum[Maxim]Franquet. A sensitive and validated method was developed to determine Tub in rat plasma. This method combined the qualitative and quantitative advantages from liquid chromatography coupled with hybrid ion trap‐time of flight mass spectrometer (HPLC‐DAD‐IT‐TOF‐MS) and a triple quadrupole–linear ion trap mass spectrometer 5500 (Qtrap 5500), owing to the narrow molecular range of Qtrap 5500 relative to the molecular weight of Tub. Initially, ion detection was achieved using negative ionization mode along with full scan on IT‐TOF‐MS. The detected precursor and product ions of Tub with the optimal mass parameters were determined on Qtrap 5500 by an online stepped optimization strategy and operated in negative multiple reaction monitoring mode. A simple methanol precipitation was employed with saikosaponin A as internal standard. The method was validated over the range from 20 to 2000 ng/mL with a lower limit of quantification of 20 ng/mL for Tub in plasma. The developed method was successfully applied to the pharmacokinetic study of Tub in rats following oral administration. Moreover, this method has some directive significance for the determination of other drugs whose parent ions exceeding the upper detection limit in Qtrap 5500.

Ding, Wenzheng; Wang, Hanxue; Zhou, Quan; Wu, Jinrong; Cheng, Xuemei; Wang, Changhong

doi: 10.1002/bmc.4341pmid: 30007052

Gentiana Macrophylla Radix (GMR) is officially used as traditional Chinese medicine, but easily confused with Gentianae Radix et Rhizoma (GRR) and adulterants. This study aimed to establish an HPLC method for qualitative and quantitative analysis of GMR based on characteristic components, anofinic acid and its derivatives. HPLC analysis was performed on a C18 column with gradient elution using acetonitrile and 0.1% phosphoric acid as mobile phase, and detected at 240 nm by conventional methodology validation. For fingerprint analysis, RSDs of relative retention times and relative peak areas of the characteristic peaks were within 0–1.10 and 0–4.08%, respectively. For determination of 2‐methoxyanofinic acid, the calibration curve showed good linearity (R2 > 0.9999) within the test range. The RSDs of precision, repeatability and stability test did not exceed 2.46, 0.83 and 1.11%, respectively. The average recoveries were between 95.08 and 103.05% with RSDs ≤2.29%. The results showed that there was no significant difference among the four species of GMR, but there were significant differences among GMR, GRR and spurious breeds by principal component analysis and hierarchical cluster analysis. Anofinic acid and its derivatives, as the characteristic markers, could be used for the identification and quality control of GMR.

Mulubwa, Mwila; Mugabo, Pierre

doi: 10.1002/bmc.4325pmid: 29947117

A chromatographic method has been developed and validated for the first time for analysis of terizidone in plasma. Terizidone was extracted from plasma by protein precipitation using a mixture of acetonitrile and methanol (1:1, v/v). The chromatographic separation was achieved with a gradient of acetonitrile and water both containing 0.1% formic acid on a Supelco Discovery® HS C18 (150 × 4.6 mm, 5 μm) reversed‐phase column. Propranolol was used as the internal standard. The total run‐time was 18 min. The calibration standard concentrations ranged between 3.125 and 200 μg/mL and calibration curves were linear with coefficient of determination values in the range of 0.9988–0.9999. The inter‐ and intra‐day assay precision (percentage relative standard error) was <15% while mean accuracy was 107%. The mean extraction efficiencies of terizidone and IS were 76 and 89%, respectively. The validation results demonstrated that the method was selective and sensitive, and that terizidone was stable under the studied conditions. The method was successfully applied in a population pharmacokinetic study. The mean plasma concentration of terizidone in patients at all sampling time points was 51.8 ± 28 μg/mL. The method was simple, cheap and hence suitable for therapeutic drug monitoring of terizidone.

Cassol, José Pedro Etchepare; Souza Barbosa, Fábio; Garcia, Cássia V.; Mendez, Andreas S.L.

doi: 10.1002/bmc.4348pmid: 30047558

The antipsychotic paliperidone was investigated with a focus on stability, degradation impurities and kinetics reaction profile. Osmotic tablets 3 mg (OROS®) were subjected to extraction in an ultrasonic bath and the resulting acidic solution was stressed by forced conditions. Degraded samples were monitored by HPLC–DAD in different storage times for acidic and alkaline hydrolysis, oxidation, heat and photolysis. Photolysis was shown to be a strong degradation factor, with a drug content of 24.64% remaining after 24 h. Oxidation (H2O2 18%) caused a slow decomposition, with a drug content of 83.49% remaining after 72 h. Through kinetics graphics, first‐order reactions were found for oxidation, heat and photolysis. By UPLC–MS analysis, the degraded matrix could be investigated for identification of impurities with m/z 445.3128, m/z 380.8906, m/z 364.9391, m/z 232.9832 and m/z 217.0076, allowing the identification of derivatives N‐oxide and with modifications in the lactam, benzisoxazole and pyrimidine rings. Paliperidone in liquid state, like analytical solutions or formulation, must be carefully handled to avoid drug exposure, specially in storage conditions.

Diego, Marta; Correa, Diana; Mennickent, Sigrid; Godoy, Ricardo; Vergara, Carola

doi: 10.1002/bmc.4340pmid: 30001570

Vortioxetine hydrobromide (VOR), is a novel antidepressant used for the treatment of major depressive disorder. It has a chemical structure susceptible to degradation, therefore it is important to have suitable analytical methods to determine VOR in presence of its main degradation products (DP), because if the compound degrades, this could result in diminution of the therapeutic activity and safety. A simple HPLC method with photodiode array detection was developed and validated for determination of VOR in bulk and tablets, in the presence of its major DP. The drug was subjected to oxidative, hydrolytic, and photolytic stress conditions, showing significant degradation under oxidation with the formation of one DP, which was identified by ESI‐MS/MS. A C18 column was used, with mobile phase consisting of acetonitrile and water with acetic acid and triethylamine in isocratic elution mode, with detection at 228 nm and 1.0 mL/min flow rate. The assay was linear in the 25–125 μg/mL concentration range. For precision, the RSD was <1.8%, the recovery was 100.0–101.6%, and the method demonstrated adequate selectivity. The method was successfully applied to quantify VOR in tablets. The results showed that the method is useful for routine analysis and for quality control purposes.

Luo, Linda; Wen, Xiaoli; Du, Yueying; Jiang, Zhen; Guo, Xingjie

doi: 10.1002/bmc.4345pmid: 30030850

A rapid, sensitive and enantioselective method was developed and fully validated for the separation and determination of lansoprazole enantiomers in rat plasma by liquid chromatography–tandem mass spectrometry (LC–MS/MS). The analytes and the internal standard (esomeprazole) were both extracted from plasma samples by liquid–liquid extraction with diethyl ether–dichloromethane (70:30; v/v). Satisfactory resolution (Rs = 2.0) was achieved within 7.3 min on a Chiralpak ID column (250 × 4.6 mm, 5 μm) employing acetonitrile–water (60:40, v/v) as the mobile phase at a flow rate of 0.6 mL/min. The acquisition of mass spectrometric data was performed in the multiple reaction monitoring mode coupled with a positive electrospray ionization source. A comprehensive validation of this method was rigorously conducted over the concentration range of 1.00–500.0 ng/mL for both enantiomers. All of the validation data demonstrated that the desirable linearity, sensitivity, accuracy, precision, recovery and stability were attained from the proposed approach. The established method was successfully applied to a stereoselective pharmacokinetic study of lansoprazole enantiomers in rat plasma after oral administration of 3 mg/kg racemic lansoprazole or dexlansoprazole. No chiral inversion was observed during the experimental procedure.