Ning Ou

Simultaneous quantification of metronidazole, tinidazole, ornidazole and morinidazole in human saliva

The aim of this study was to develop a rapid and sensitive method for the simultaneous quantification of metronidazole (MEZ), tinidazole (TNZ), ornidazole (ONZ) and morinidazole (MNZ) in human saliva. A reversed-phase high-performance liquid chromatography (HPLC) method with ultraviolet (UV) detection at 318 nm was carried out on a C18 column, using a mixture of potassium dihydrogen phosphate buffer, acetonitrile, and methanol (55:15:30, v/v/v) as a mobile phase with a flow rate of 1.0 ml/min. The saliva samples (100 μl) were firstly deproteinized by precipitation with methanol (400 μl), after which they were centrifuged and the supernatants were directly injected into the HPLC system. This method produced linear responses in the concentration ranges of 25.2-5040.0, 23.9-4790.0, 25.4-5080.0, 25.0-5000.0 ng/ml with detection limits of 6.0, 17.6, 10.0 and 11.3 ng/ml for MEZ, TNZ, ONZ and MNZ (S/N=3), respectively. The methods were validated in terms of intra- and inter-batch precision (within 7.3% and 9.1%, respectively), accuracy, linearity, recovery and stability. The study proved that HPLC is both sensitive and selective for the simultaneous quantification of MEZ, TNZ, ONZ and MNZ in human saliva using a single mobile phase.

Hydrophilic interaction liquid chromatography coupled with tandem mass spectrometry method for the simultaneous determination of l-valine, l-leucine, l-isoleucine, l-phenylalanine, and l-tyrosine in human serum.

l-Valine, l-leucine, l-isoleucine, l-phenylalanine, and l-tyrosine are important proposed biomarkers for the early detection and diagnosis of type 2 diabetes. A simple and selective hydrophilic interaction chromatography with tandem mass spectrometry method was developed for the simultaneous determination of these amino acids in human serum, using stable isotope-labeled amino acids as internal standards. Chromatographic separation was carried out on a Syncronis HILIC column (150 mm × 2.1 mm, 5 μm) with the column temperature of 35°C and a mobile phase consisted of acetonitrile/120 mM ammonium acetate (89:11, v/v), and the run time was 11.0 min. The mass spectrometric analysis was performed using a QTRAP 5500 mass spectrometer coupled with an electrospray ionization source in positive ion mode. As these five amino acids are endogenous compounds in serum, we used the corresponding stable isotope-labeled amino acids to evaluate the matrix effect and recovery in serum. The matrix effect was 98.7-107.3%, and the recovery was 92.7-102.3%. Calibration curves spiked unlabeled amino acids in water were linear over the range of 0.200-100 μg/mL. The accuracy, inter-, and intraday precision were below 10.2%. Analytes were stable during the study. This assay method has been validated and applied to the early diagnosis research of type 2 diabetes.

Pharmacokinetics, Safety and Tolerability of Bencycloquidium Bromide, a Novel Selective Muscarinic M1/M3 Receptor Antagonist, After Single and Multiple Intranasal Doses in Healthy Chinese Subjects

AbstractBackground: Bencycloquidium bromide (BCQB) is a novel, potent and selective muscarinic M1/M3 receptor antagonist under development for the treatment of rhinorrhea in rhinitis. The pharmacokinetics and safety of BCQB in animals have been established in preclinical studies. However, no clinical pharmacokinetic data are available for BCQB in humans. Objective: The aim of this first-in-human study was to evaluate the pharmacokinetics, safety and tolerability of BCQB following single and multiple intranasal doses in healthy Chinese subjects. Methods: The clinical trial was comprised of the following four studies: (i) an open-label, single-dose escalation study to evaluate the safety and tolerability in healthy subjects after intranasal doses of BCQB ranging from 45 to 450 mg (total of six doses); (ii) an open-label, multiple-dose escalation study to assess the safety and tolerability in healthy subjects after intranasal administration with 120 and 150 mg doses of BCQB (360 and 450 μg/day) administered three times daily for 15 days; (iii) a randomized, open-label and parallel-group design to evaluate the single-dose pharmacokinetics of BCQB after intranasal dosing (45, 90, and 180 μg); and (iv) ten subjects received 120 μg of BCQB by intranasal administration, three times daily for 5 days with a final single dose on day 7 to assess its multiple-dose pharmacokinetics. Safety and tolerability of BCQB were evaluated by monitoring adverse events (AEs), ECG recordings, vital signs and clinical laboratory parameters. The pharmacokinetic parameters for BCQB were calculated by software using noncompartmental methods. Results: All AEs were mild, of limited duration and no more frequent at higher doses. There was no serious adverse event, death or withdrawal. No clinically significant change was noted in clinical laboratory parameters, cardiac parameters or vital signs. Following single intranasal dosing, BCQB was rapidly absorbed with a median time to maximum concentration (tmax) of 8 minutes for 45, 90, and 180 mg dose groups; the plasma concentration of BCQB decreased in a biphasic manner with the mean half-life (t1/2) of 8.5 hours; the maximum concentration (Cmax) and area under the plasma concentration-time curve (AUC) of BCQB increased linearly across the examined dose range of 45–180 μg. During the multiple dosing, the steady state was achieved within 3 days of 120 μg three times daily dosing of BCQB. A slightly greater AUC was observed after 5 days of multiple dosing, with the mean accumulation ratio of 1.26; however, the half-life was unchanged. Conclusion: BCQB was safe and well tolerated in healthy Chinese subjects when administered intranasally with single and multiple doses across the doses studied. The mean Cmax and AUC increased proportionally to the studied doses, and the steady state was achieved within 3 days after three times daily dosing. A slight accumulation of BCQB following multiple dosing was observed. The pharmacokinetics, safety and tolerability profiles of BCQB pose it as a good candidate for further development in the treatment of rhinorrhea in rhinitis.

Phase I Clinical Study of Edaravone in Healthy Chinese Volunteers

ObjectiveThe objective of this study was to investigate the safety and pharmacokinetics of edaravone administered by single or successive intravenous infusions in healthy Chinese volunteers.MethodsA total of 30 subjects (15 males and 15 females) were recruited and randomly assigned to three groups receiving edaravone doses of 20, 30, and 60 mg. All subjects received a single dose of edaravone during a 30-minute period, and only the 30 mg dose group continued to receive the same dose successively by intravenous infusion twice daily for the next 5 days. Plasma concentrations of edaravone were monitored by high-performance liquid chromatography at the following times: 15, 30, 45, 60, 75, 105, 165, 225, 300, 390, 480, 600, and 720 minutes after edaravone administration.ResultsThe area under the plasma concentration-time curve during a dosage interval (AUCτ) values of the single dose in the 20, 30, and 60 mg dose groups were 3.64±1.37, 5.17 ± 0.93, and 11.25 ± 3.42 mg · h/L, respectively, while in the group receiving repeated dosing of 30 mg, the mean AUCτ value was 5.06 ± 0.89mg · h/L. The corresponding maximum plasma drug concentration (Cmax) values were 1599.0 ± 382.6, 2378.7 ± 316.7, and 4540.1 ± 901.1 ng/mL, respectively, in the single-dose groups, and 2479.1 ± 477.9 ng/mL in the 30 mg repeated-dose group. The mean AUCτ and Cmax ratios between the repeated-dose group and the single-dose groups were 0.98 and 1.04. All laboratory test abnormalities (including increased alanine transaminase and triacylglycerol levels, and decreased white blood cell counts and creatinine levels) were mild and tolerable. All abnormal blood biochemical indices returned to normal levels after 7 days.ConclusionEdaravone was safe and well tolerated in the volunteers and displayed linear increases in the Cmax and AUCτ values.

A simple LC–MS/MS method for determination of sitafloxacin in human urine

Sitafloxacin is a new fluoroquinolone antimicrobial agent with high activity. In this article, we reported a simple, rapid and specific LC-MS/MS method for accurate determination of sitafloxacin concentrations in human urine from healthy volunteers in detail. A two-step dilution method for the analysis of sitafloxacin in human urine using LC coupled to positive MS/MS has been developed and validated according to US FDA guidelines and Chinese State Food and Drug Administration (CFDA) guidelines for the validation of bioanalytical methods. The method uses 50 μL of urine and covers a working range from 0.025 to 20 μg/mL with a LLOQ of 0.025 μg/mL. This new LC-MS/MS assay is sensitive and specific.

Effects of CYP3A4*1G and CYP3A5*3 Polymorphisms on Pharmacokinetics of Tylerdipine hydrochloride in Healthy Chinese Subjects.

Abstract The aim of this analysis was to explore the influence of CYP3A4*1G and CYP3A5*3 polymorphisms on the pharmacokinetics of tylerdipine in healthy Chinese subjects. A total of 64 and 63 healthy Chinese subjects were included and identified as the genotypes of CYP3A4*1G and CYP3A5*3, respectively. Plasma samples were collected for up to 120 h post-dose to characterize the pharmacokinetic profile following single oral dose of the drug (5, 15, 20, 25 and 30 mg). Plasma levels were measured by a high-performance liquid chromatography-mass spectrometry (LC-MS/MS). The pharmacokinetic parameters were calculated using non-compartmental method. The maximum concentration (Cmax) and the area under the curve (AUC0–24 h) were all corrected by the dose given. In the wild-type group, the mean dose-corrected AUC0–24 h was 1.35-fold larger than in CYP3A4*1G carriers (p = .018). Among the three CYP3A5 genotypes, there showed significantly difference (p = .008) in the t1/2, but no significant difference was observed for the AUC0–24 h and Cmax. In subjects with the CYP3A5*3/*3 genotype, the mean t1/2 was 1.35-fold higher than in CYP3A5*1/*1 group (p = .007). And the t1/2 in CYP3A5*3 carriers also was 1.32-fold higher than in the wild-type group (p = .004). CYP3A4*1G and CYP3A5*3 polymorphisms may influence tylerdipine pharmacokinetic in healthy Chinese subjects.

Simultaneous quantification of antofloxacin and its major metabolite in human urine by HPLC--MS/MS, and its application to a pharmacokinetic study.

This study presents a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method for the simultaneous determination of antofloxacinin and its main metabolite - N-demethylated metabolite (N-DM) - in human urine. Ornidazole was used as the internal standard. This was a clinical urine recovery study, in which 10 healthy Chinese volunteers were intravenously administered a single 200 mg dose of antofloxacin hydrochloride. Compounds were extracted by albumen precipitation, after which samples were isocratically eluted using a Poroshell 120 SB-C18 column, and were analysed using HPLC-MS/MS under electronic spray ionization positive ion mode. The method was successfully applied in a urine pharmacokinetic study of antofloxacinin, with a detection range of 0.02/0.01 to 200/100 μg/mL (for antofioxacin/N-DM).The average percentages of antofioxacin/N-DM measured in urinary excretion frp, 10 volunteers were 54.9 ± 5.7/8.2 ± 2.5% in 120 h duration.

Safety and Tolerability of Bismuthyl Ecabet Suspension, a Novel Anti-Ulcer Agent, following Single and Multiple Oral Dose Administration in Healthy Chinese Subjects

AbstractBackground: Bismuthyl ecabet is a combination of sulfodehydroabietic acid and bismuth, which forms a new type of salt that is useful in treating peptic ulcers and gastritis. Objective: This study was designed to assess the safety and tolerability of bismuthyl ecabet suspension in healthy Chinese subjects. Methods: For the study 77 volunteers were randomized into single- or multiple-dose groups for oral administration of bismuthyl ecabet 200–1600 mg once daily or 1200 mg twice daily for 7 days. Safety and tolerability were assessed by adverse events, physical examination and serum biochemistry. Results: In both the single- and multiple-dose studies, no severe adverse events were observed in any of the volunteers. The main adverse events caused by the drug in single-dose groups were an increase in serum alanine transaminase (ALT), γ-glutamyl transpeptidase, blood urea nitrogen, total bilirubin and skin rash. The numbers of adverse events judged to be possibly related to the drug were 2/18 in the 400 mg, 2/18 in the 800 mg, 1/8 in the 1200 mg, and none in the 200 or 1600 mg dose groups. In the multiple-dose studies, an increased serum ALT and aspartate transaminase (AST) was found in one subject after 7 days of administration of the drug. All serum biochemistry returned to normal levels and skin rash resolved after 7 days without any special treatment. Conclusion: Bismuthyl ecabet was shown to be safe and well tolerated in healthy Chinese subjects. The oral dosing regimen selected for subsequent phase II/III clinical trials was 800 mg twice daily.

Determination of palonosetron in human urine by LC–MS/MS

BACKGROUND Palonosetron is used for the prevention of chemotherapy-induced nausea and vomiting. However, quantification of this drug in human urine has been rare. RESULTS A one-step dilution method for the analysis of palonosetron in human urine using LC coupled to positive MS/MS has been developed and validated according to US FDA guidelines. The method uses 200 µl of urine and covers a working range from 2.5-1000 ng/ml with a LLOQ of 2.5 ng/ml. CONCLUSION This new LC-MS/MS assay is sensitive and specific despite using an external standard method. It is suitable for clinical studies of palonosetron.

Development and validation of two LC-MS/MS methods to assay urinary tylerdipine hydrochloride and its metabolites in healthy Chinese subjects

For quantitative assaying tylerdipine hydrochloride, and its two primary metabolites (M2 and M4) in human urine, two sensitive and accurate LC-MS/MS methods were firstly developed and validated, where multiple reaction monitoring (MRM) was applied under positive electrospray ionization mode for tylerdipine and negative electrospray ionization mode for M2/M4, respectively. Urinary proteins were precipitated using acetonitrile, and deuterated isotopes of tylerdipine and M4 ([D5]‑tylerdipine and [D6]-M4) were used as internal standards. Triton X-100, a good surfactant, was used to prevent the adsorption. An Agilent Poroshell 120 column was employed for chromatographic separation of the analytes with the mobile phases of 2 mM ammonium formate solution (containing 0.1% formic acid) and acetonitrile (45:55 for tylerdipine and 75:25 for the M2/M4, v/v). Flow rate was 0.3 mL/min. Calibration curves for tylerdipine, M2 and M4 in urine were linear over the ranges of 0.02-10 ng/mL, 2-1500 ng/mL and 0.5-200 ng/mL, respectively. The precision, accuracy, specificity and stability of two methods all evaluated and achieved the acceptable criteria. The LC-MS/MS methods were successfully applied to assay urinary excretion of tylerdipine and the metabolites in healthy Chinese subjects who orally received a single dose of 20 mg tylerdipine tablet. Generally, the urinary excretion of the two primary metabolites accounted for 11.7% of the total dose of tylerdipine in healthy Chinese subjects, while little tylerdipine was recovered in urine.