Pharmacokinetics and Safety of Eptinezumab in Healthy Chinese Participants: A Randomized Clinical Trial.

BACKGROUND AND OBJECTIVE: Most evidence suggests that the pharmacokinetics of monoclonal antibodies (mAbs) are not meaningfully altered by patient characteristics, including racial/ethnic differences. Nevertheless, the pharmacokinetic profile of eptinezumab has not been evaluated in a Chinese population. This study was designed to confirm the hypothesis that the pharmacokinetic profile of the anti-calcitonin gene-related peptide mAb, eptinezumab, is similar in healthy Chinese individuals to that of healthy non-Asian individuals and non-Asian patients with migraine. METHODS: Over a study period of 12 weeks, healthy adult Chinese participants (N = 20) were randomized (1:1) to receive a single intravenous dose of eptinezumab 100 mg (n = 10) or 300 mg (n = 10) in a prospective, single-site, open-label parallel-group trial. Blood samples for the evaluation of plasma eptinezumab concentrations were obtained over 84 days, and standard pharmacokinetic parameters were derived. RESULTS: Mean maximum plasma concentrations (Cmax) of eptinezumab occurred 1.0-1.5 h post start of infusion, were similar between the 100 mg and 300 mg dose groups, and slowly declined in a biphasic manner. Cmax and area under the drug concentration-time curve (AUC) increased in a dose-proportional manner. Volume of distribution and clearance were similar between the 100 mg and 300 mg dose groups, and half-life was 22.5-28.1 days. Eptinezumab was generally well tolerated with no new safety signals identified. Only one participant, randomized to the 100 mg dose group, was positive for eptinezumab anti-drug antibodies, but negative for neutralizing antibodies, with no impact on pharmacokinetics. CONCLUSION: The pharmacokinetic profile of eptinezumab in healthy Chinese individuals was generally similar to that reported for non-Asian populations with migraine, and eptinezumab was generally well tolerated. Evaluation of immunogenicity showed no evidence of an impact of anti-drug antibodies or neutralizing antibodies on safety profiles. This supports the globally approved doses of 100 mg and 300 mg as being appropriate for Chinese patients with episodic migraine or chronic migraine.

Safety and immunogenicity of a modified COVID-19 mRNA vaccine, SW-BIC-213, as a heterologous booster in healthy adults: an open-labeled, two-centered and multi-arm randomised, phase 1 trial.

BACKGROUND: We assessed the safety and immunogenicity of a core-shell structured lipopolyplex (LPP) based COVID-19 mRNA vaccine, SW-BIC-213, as a heterologous booster in healthy adults. METHODS: We conducted an open-labeled, two-centered, and three-arm randomised phase 1 trial. Healthy adults, who had completed a two-dose of inactivated COVID-19 vaccine for more than six months, were enrolled and randomized to receive a booster dose of COVILO (inactivated vaccine) (n = 20) or SW-BIC-213-25µg (n = 20), or SW-BIC-213-45µg (n = 20). The primary study endpoint was adverse events within 30 days post-boosting. The secondary endpoint was the titers of binding antibodies and neutralizing antibodies against the wild-type (WT) of SARS-CoV-2 as well as variants of concern in serum. The exploratory endpoint was the cellular immune responses. This trial was registered with http://www.chictr.org.cn (ChiCTR2200060355). FINDINGS: Between Jun 6 and Jun 22, 2022, 60 participants were enrolled and randomized to receive a booster dose of SW-BIC-213 (25 µg, n = 20, or 45 µg, n = 20) or COVILO (n = 20). The baseline demographic characteristics of the participants at enrollment were similar among the treatment groups. For the primary outcome, injection site pain and fever were more common in the SW-BIC-213 groups (25 µg and 45 µg). Grade 3 fever was reported in 25% (5/20) of participants in the SW-BIC-213-45µg group but was resolved within 48 h after onset. No fatal events or adverse events leading to study discontinuation were observed. For secondary and exploratory outcomes, SW-BIC-213 elicited higher and longer humoral and cellular immune responses than that in the COVILO group. INTERPRETATION: SW-BIC-213, a core-shell structured lipopolyplex (LPP) based mRNA vaccine, was safe, tolerable, and immunogenic as a heterologous booster in healthy Chinese adults. FUNDING: Shanghai Municipal Government, the Science and Technology and Economic Commission of Shanghai Pudong New Area, and mRNA Innovation and Translation Center of Shanghai.

Comparison of Pharmacokinetics of Aprepitant in Healthy Chinese and Caucasian Subjects.

PURPOSE: Aprepitant is used to prevent nausea and vomiting associated with moderately and highly emetogenic chemotherapy. In this open-label, 2-period study, the safety, tolerability, and pharmacokinetics (PK) of aprepitant (EMEND®) were evaluated in healthy Chinese and Caucasian subjects. PATIENTS AND METHODS: Twelve Chinese and 12 Caucasian subjects were to receive a 125 mg single-dose of aprepitant during period 1; subsequently, after 15 days washout, only Chinese subjects were to receive the 3-day regimen in period 2. In each period, serial blood samples were collected and analyzed by a validated liquid chromatographic and mass spectrometric method to characterize aprepitant PK across both groups. RESULTS: In both Chinese and Caucasian subjects, there were no serious adverse events. AUC0-∞, Cmax, Tmax, and t1/2 were largely comparable between the two ethnicities. Comparing the result of period 1 in Chinese and Caucasian subjects, the geometric least-squares mean maximum plasma concentrations (Cmax) were 1482 ng/mL and 1435 ng/mL, and the area under the concentration-time curve (AUC0-∞) 34,035 hr·ng/mL and 34,188 hr·ng/mL. In period 2, the geometric mean AUC0-24 on Day 1 and Day 3 were 19,446 hr·ng/mL and 27,843 hr·ng/mL, and the geometric mean Cmax on Day 1 and Day 3 were 1423 ng/mL and 1757 ng/mL, respectively. CONCLUSION: Aprepitant is generally safe and well tolerated in healthy Chinese and Caucasian subjects. Aprepitant PK is comparable between Chinese and Caucasian subjects following single-dose administration. The PK following a clinical 3-day regimen on healthy Chinese subjects has been characterized.

A Phase 1, Randomized, Double-Blind, Single-Dose, Placebo-Controlled Safety, Tolerability, And Pharmacokinetic/Pharmacodynamic Study Of Evolocumab In Healthy Chinese Subjects.

PURPOSE: Evolocumab is a human monoclonal antibody that reduces circulating low-density lipoprotein cholesterol (LDL-C) by inhibiting proprotein convertase subtilisin/kexin type 9 (PCSK9). Data on evolocumab pharmacokinetics and pharmacodynamics are derived mostly from Caucasian populations. The objectives of this study were to characterize the single-dose pharmacokinetic and pharmacodynamic parameters, safety, and tolerability of evolocumab in healthy Chinese subjects. SUBJECTS AND METHODS: This was a phase 1, randomized, double-blind, placebo-controlled study (CTR20150465). Two parallel cohorts were randomized 5:1 to receive single subcutaneous injections of either evolocumab (140 mg or 420 mg) or placebo. Pharmacokinetics, pharmacodynamics, and safety were evaluated through day 85. The primary endpoints were maximum concentration (Cmax) and area under the drug concentration-time curve from time 0 to time of last quantifiable concentration (AUClast). RESULTS: Thirty-six men (median age 26) were enrolled to receive evolocumab 140 mg (n=15), evolocumab 420 mg (n=15), or placebo (n=6). After 140 mg and 420 mg evolocumab, mean (SD) Cmax was 13.8 (3.6 µg/mL and 67.6 (15.2) µg/mL, respectively, and mean (SD) AUClast was 166 (55) day·µg/mL and 1110 (274) day·µg/mL, respectively. LDL-C declined reversibly, with reductions of 70% at 140 mg and 71% at 420 mg. Maximum effects on LDL-C and PCSK9 levels were reached by day 15 and 24 hrs, respectively, at 140 mg, and by day 22 and 4 hrs, respectively, at 420 mg. No serious adverse events occurred and the overall incidence of treatment-emergent adverse events was similar for evolocumab and placebo: 26.7% (140 mg) and 33.3% (placebo); 66.7% (420 mg) and 66.7% (placebo). CONCLUSION: In this population of healthy Chinese subjects, single 140 mg and 420 mg doses of evolocumab exhibited nonlinear kinetics and more than dose-proportional increases in exposure, were associated with up to 71% reduction in LDL-C, and demonstrated a safety profile similar to placebo.

Pharmacokinetics, Safety and Tolerability of Chiglitazar, A Novel Peroxisome Proliferator-Activated Receptor (PPAR) Pan-Agonist, in Healthy Chinese Volunteers: A Phase I Study.

BACKGROUND AND OBJECTIVES: Chiglitazar is a novel configuration-restricted non-thiazolidinedione peroxisome proliferator-activated receptor pan-agonist currently in the Phase III clinical development stage for type 2 diabetes mellitus patients. The objective of this Phase I study was to evaluate the pharmacokinetics, safety and tolerability of single and multiple doses of chiglitazar tablets taken orally and the effect of food on its pharmacokinetics in healthy Chinese subjects. METHODS: A single-centre, open-label, randomised, two-stage Phase I study was carried out. In the first-stage study, we evaluated a single dose of 8, 16, or 32 mg, and multiple doses of 16 mg, taken once daily for 9 days. The effect of food consumption was also studied in this stage. In the second-stage study, a greater range of single doses (24, 48 or 72 mg) were further evaluated. Pharmacokinetics, safety and tolerability profiles were assessed at each study stage. RESULTS: After a single oral dose of chiglitazar, at doses ranging from 8 to 72 mg, the maximum plasma concentration (Cmax) and area under the concentration-time curve (AUC) were proportionally increased (165-1599 ng/mL for the mean Cmax and 1356-12,584 ng·h/mL for the mean AUC0-t), with low inter-subject variability. There were no significant changes in the mean terminal phase half-life (t1/2), which ranged from 9.0 to 11.9 h, and the clearance and volume of distribution were similar for all evaluated doses. The results from the examination of multiple dose of 16 mg once daily for nine consecutive days showed that a steady-state condition was achieved by Day 6. There was no apparent accumulation of chiglitazar observed at Day 9, as compared with the first administration. While food increased the AUC0-t of chiglitazar by about 13%, there were no effects on other parameters, including Cmax, Tmax and t1/2. There were no serious or severe adverse events observed in the single- or multiple-dose studies. CONCLUSIONS: Chiglitazar tablets showed a good dose-dependent linear pharmacokinetic profile in the dose range of 8-72 mg. There was no accumulation after multiple daily administration of chiglitazar at a dose of 16 mg.  High-fat/calorie food increased the absorption of the drug, but there were no significant changes in exposure and other pharmacokinetic parameters. Chiglitazar was safe and well tolerated in healthy Chinese subjects at the dose levels and administration regimens evaluated.

An UHPLC-MS/MS method for simultaneous quantification of human amyloid beta peptides Aß1-38, Aß1-40 and Aß1-42 in cerebrospinal fluid using micro-elution solid phase extraction.

Amyloid beta (Aß) peptides in cerebrospinal fluid are extensively estimated for identification of Alzheimer's disease (AD) as diagnostic biomarkers. Unfortunately, their pervasive application is hampered by interference from Aß propensity of self-aggregation, nonspecifically bind to surfaces and matrix proteins, and by lack of quantitive standardization. Here we report on an alternative Ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for simultaneous measurement of human amyloid beta peptides Aß1-38, Aß1-40 and Aß1-42 in cerebrospinal fluid (CSF) using micro-elution solid phase extraction (SPE). Samples were pre-processing by the mixed-mode micro-elution solid phase extraction and quantification was performed in the positive ion multiple reaction monitoring (MRM) mode using electrospray ionization. The stable-isotope labeled Aß peptides 15N51- Aß1-38, 15N53- Aß1-40 and 15N55- Aß1-42 peptides were used as internal standards. And the artificial cerebrospinal fluid (ACSF) containing 5% rat plasma was used as a surrogate matrix for calibration curves. The quality control (QC) samples at 0.25, 2 and 15ng/mL were prepared. A "linear" regression (1/x2 weighting): y=ax+b was used to fit the calibration curves over the concentration range of 0.1-20ng/mL for all three peptides. Coefficient of variation (CV) of intra-batch and inter-batch assays were all less than 6.44% for Aß1-38, 6.75% for Aß1-40 and 10.74% for Aß1-42. The precision values for all QC samples of three analytes met the acceptance criteria. Extract recoveries of Aß1-38, Aß1-40 and Aß1-42 were all greater than 70.78%, both in low and high QC samples. The stability assessments showed that QC samples at both low and high levels could be stable for at least 24h at 4°C, 4h at room temperature and through three freeze-thaw cycles without sacrificing accuracy or precision. And no significant carryover effect was observed. This validated UHPLC/MS/MS method was successfully applied to the quantitation of Aß peptides in real human CSF samples. Our work may provide a reference method for simultaneous quantitation of human Aß1-38, Aß1-40 and Aß1-42 from CSF.

Comparison of multifactor scoring systems and single serum markers for the early prediction of the severity of acute pancreatitis.

BACKGROUND: The purpose of this study was to clarify whether the current scoring systems and single serum markers used in pancreatitis remain applicable for the early prediction of infected pancreatic necrosis (IPN) and the severity and mortality of acute pancreatitis (AP) in accordance with the revised Atlanta and determinant-based classifications. METHODS: Demographic, clinical, and laboratory data from 708 consecutive patients with AP were prospectively collected between January 2011 and December 2012. The severity was classified using the revised Atlanta and determinant-based classification systems. The predictive accuracies for moderately severe AP (MSAP), severe AP (SAP), critically severe AP (CAP), IPN, and mortality were measured using area under the receiver operating characteristic curves. RESULTS: The receiver operating characteristic analysis showed that the multifactor scoring systems and single serum markers had a low predictive accuracy regarding moderately severe AP. The Acute Physiology and Chronic Health Evaluation (APACHE) II score had the highest accuracy in predicting SAP with area under the curve (AUC) values of 0.75 (95% CI = 0.71-0.79) and 0.77 (95% CI = 0.73-0.81) at 24 and 48 h after admission, respectively. Procalcitonin was the most accurate predictor for CAP and IPN, with respective AUCs of 0.86 (95% CI = 0.82-0.89) and 0.83 (95% CI = 0.78-0.87) at 48 h after admission. In predicting mortality, both the APACHE II score and blood urea nitrogen had the highest accuracy. CONCLUSIONS: The APACHE II score had the highest predictive accuracy for SAP and mortality as defined by the revised Atlanta classification, whereas procalcitonin was the most accurate predictor for CAP and IPN.

Evaluation of the in vitro and in vivo metabolic pathway and cytochrome P450 inhibition/induction profile of Huperzine A.

Huperzine A (HupA), one of the reversible and selective acetylcholinesterase inhibitors derived from Chinese herb Huperzia Serrata, possesses affirmative action of ameliorating cognitive dysfunction of Alzheimer's disease. Up to now, the effects of HupA on human cytochrome P450s (CYPs) have not been fully elucidated. The purpose of the present study was to clarify the metabolic pathway of HupA in vitro and in vivo, and to evaluate the CYPs inhibition/induction profile of HupA in vitro. The catalytic activity of CYP enzymes (CYP1A2, 2A6, 2C9, 2C19, 2D6, 2E1 and 3A4) was measured by the quantification of specific enzyme substrates using validated liquid chromatography-tandem mass spectrometry (LC/MS/MS) methods. The in vivo metabolic pathway evaluation was performed in an open, single-dose pharmacokinetic study of HupA in fourteen elderly subjects, with urine collecting at certain intervals. In human liver microsomes, HupA (10 ng/mL) was not metabolized within 90 min, and it showed negligible inhibition against these CYP isoforms within 0.2-100 ng/mL. In human liver hepatocytes, the activities of CYP1A2 and CYP3A4 were not significantly altered when incubated at 2 or 20 ng/mL of HupA. After oral administration of 0.1 mg HupA, the total proportion of HupA excreted through urine was relatively high, accounting to 35± 9% at the limited time period of 48 h. These results suggest that HupA is substantially excreted by kidney unchanged rather than metabolized by human liver, and is unlikely to cause clinically relevant drug-drug interaction (DDI) when co-administrated with drugs that are metabolized by CYP isoenzyme system.

Population pharmacokinetic modeling and simulation of huperzine A in elderly Chinese subjects.

AIM: Our preliminary results show that huperzine A, an acetylcholinesterase inhibitor used to treat Alzheimer's disease (AD) patients in China, exhibits different pharmacokinetic features in elderly and young healthy subjects. However, its pharmacokinetic data in elderly subjects remains unavailable to date. Thus, we developed a population pharmacokinetic (PPK) model of huperzine A in elderly Chinese people, and identified the covariate affecting its pharmacokinetics for optimal individual administration. METHODS: A total of 341 serum huperzine A concentration records was obtained from 2 completed clinical trials (14 elderly healthy subjects in a phase I pharmacokinetic study; 35 elderly AD patients in a phase II study). Population pharmacokinetic analysis was performed using the non-linear mixed-effect modeling software Phoenix NLME1.1.1. The effects of age, gender, body weight, height, creatinine, endogenous creatinine clearance rate as well as drugs administered concomitantly were analyzed. Bootstrap and visual predictive checks were used simultaneously to validate the final population pharmacokinetics models. RESULTS: The plasma concentration-time profile of huperzine A was best described by a one-compartment model with first-order absorption and elimination. Age was identified as the covariate having significant influence on huperzine A clearance. The final PPK model of huperzine A was: CL (L/h)=2.4649(*)(age/86)((-3.3856)), Ka=0.6750 h(-1), V (L)=104.216. The final PPK model was demonstrated to be suitable and effective by the bootstrap and visual predictive checks. CONCLUSION: A PPK model of huperzine A in elderly Chinese subjects is established, which can be used to predict PPK parameters of huperzine A in the treatment of elderly AD patients.

Pharmacokinetics and safety of ezetimibe/simvastatin combination tablet: an open-label, single-dose study in healthy Chinese subjects.

BACKGROUND AND OBJECTIVES: Ezetimibe/simvastatin combination tablet has been approved for the treatment of high low-density lipoprotein cholesterol (LDL-C) levels in patients with primary hypercholesterolaemia or mixed hypercholesterolaemia as adjunctive therapy to diet, when diet alone is insufficient in lowering cholesterol. The aims of this study were to assess the pharmacokinetics and safety of an ezetimibe/simvastatin combination tablet after oral single-dose administration in healthy Chinese subjects including sex-related differences in pharmacokinetics. METHODS: This was an open-label, single-dose study. Twelve healthy subjects (six males and six females) received a single dose of an ezetimibe/simvastatin combination tablet (ezetimibe 10 mg and simvastatin 40 mg). The pharmacokinetic parameters for ezetimibe and simvastatin were assessed by determining total ezetimibe, free ezetimibe, simvastatin and simvastatin acid concentrations using a validated liquid chromatography-tandem mass spectrometry method. Safety was evaluated by monitoring adverse events, laboratory assays, vital signs, physical examinations and 12-lead electrocardiograms. RESULTS: The pharmacokinetic parameters (mean ± SD) for total ezetimibe and free ezetimibe following a single dose were: maximum plasma drug concentration (C(max)) 81.56 ± 26.62 and 9.40 ± 6.17 ng/mL; time to reach C(max) (t(max)) 0.93 ± 0.30 and 1.25 ± 1.27 h; elimination half-life (t(½)) 24.32 ± 13.27 and 18.90 ± 9.66 h, and mean area under the plasma concentration-time curve from time zero to the time of the last measurable concentration (AUC(last)) 579.06 ± 241.45 and 126.01 ± 69.01 ng·h/mL, respectively. The pharmacokinetic parameters (mean ± SD) for simvastatin and simvastatin acid following a single dose were: C(max) 11.92 ± 5.50 and 3.37 ± 1.78 ng/mL, t(max) 0.98 ± 0.28 and 3.73 ± 1.68 h, t(½) 4.19 ± 1.81 and 7.65 ± 7.96 h, and mean AUC(last) 33.63 ± 20.41 and 32.50 ± 18.79 ng·h/mL. Higher AUC(last) and AUC from time zero to infinity (AUC(∞)), and lower apparent total body clearance of drug from plasma after oral administration (CL/F) for total ezetimibe and free ezetimibe were observed in female subjects compared with those in male subjects. There were no differences between the pharmacokinetic parameters of simvastatin and simvastatin acid for female and male subjects in the study. CONCLUSION: Ezetimibe/simvastatin combination tablet has a generally favourable safety and tolerability profile in healthy Chinese subjects. A statistically significant difference with regard to sex in the pharmacokinetics of ezetimibe was observed. Sex had no effect on the pharmacokinetics of simvastatin and simvastatin acid.

The effect of CYP2C19 activity on pharmacokinetics of lansoprazole and its active metabolites in healthy subjects.

CONTEXT: Lansoprazole is a gastric proton-pump inhibitor and has been demonstrated to be effective in the treatment of various peptic diseases. The effects of CYP2C19 activity on the pharmacokinetics of lansoprazole and its active metabolites in Chinese subjects have not previously been evaluated. OBJECTIVE: The study aimed to evaluate the effects of CYP2C19 activity in healthy Chinese volunteers. MATERIALS AND METHODS: Twenty-two healthy volunteers were recruited for an open trial and received a single dose of 30 mg lansoprazole. Using a validated LC-MS/MS method, we measured the plasma concentrations of lansoprazole, 5-hydroxylansoprazole, and lansoprazole sulfone. The genotype of CYP2C19 was identified by polymerase chain reaction (PCR) analysis of single nucleotide polymorphisms (SNPs). Subjects were genotypically classified into the following three groups on the basis of PCR-SNP analysis for CYP2C19: homozygous EM (hmEM) group, heterozygous EM (htEM) group, and PM group. To test differences in pharmacokinetic parameters among the three groups, analysis of variance (ANOVA) after log-transformation of data was used. RESULTS AND CONCLUSION: Our results indicated that there were significant differences (p < 0.001) between the hmEM and PM groups, between the htEM and PM groups, and between the hmEM and htEM groups in C(max), AUC(0-t), and AUC(0-inf) of lansoprazole and lansoprazole sulfone. There were also significant differences (p < 0.001) between the hmEM and PM groups, and between the htEM and PM groups in C(max) of 5-hydroxylansoprazole.

Pharmacokinetics of rosuvastatin in healthy Chinese volunteers living in China: a randomized, open-label, ascending single- and multiple-dose study.

BACKGROUND: Cross-study comparisons suggest that systemic exposure (AUC) to rosuvastatin calcium, a 3-hydroxy-3-methylglutaryl coenzyme A-reductase inhibitor, may be approximately 2-fold higher in Asian subjects living in Asian countries than in white subjects living in Western countries. OBJECTIVE: This study was conducted to determine the pharmacokinetic characteristics of rosuvastatin and its metabolites after single and multiple doses of rosuvastatin in healthy Chinese subjects living in China. METHODS: This was an open-label, ascending single- and multiple-dose study. Subjects were randomly assigned to receive rosuvastatin 5, 10, or 20 mg. Each subject received 1 tablet of the assigned treatment on day 1 and days 4 through 10. Plasma concentrations of rosuvastatin, N-desmethyl rosuvastatin, and rosuvastatin lactone were measured through 72 hours after administration of single doses and through 96 hours after administration of multiple doses. Blood samples were obtained within 30 minutes before dosing on days 7, 8, and 9 for the assessment of pharmacokinetic parameters at steady state. Noncompartmental pharmacokinetic analysis was performed to determine the C(max) and AUC(0-t) for rosuvastatin, N-desmethyl rosuvastatin, and rosuvastatin lactone after single and multiple doses of rosuvastatin. Tolerability assessments were conducted throughout the study. RESULTS: Of the 36 enrolled subjects, only 1 was female. The mean age of subjects in the rosuvastatin 5-, 10-, and 20-mg groups was 22.4, 21.3, and 22.4 years, respectively. Weight and height ranged from 54 to 85 kg and from 161 to 189 cm, respectively. Geometric mean C(max) values for rosuvastatin after administration of single doses of rosuvastatin 5, 10, and 20 mg were 8.33, 10.76, and 19.17 ng/mL, respectively; the corresponding geometric mean AUC(0-t) values were 57.63, 88.89, and 163.87 ng . h/mL. At steady state, values for C(max) were 8.31, 8.41, and 20.73 ng/mL; the corresponding geometric mean AUC values were 64.87, 77.29, and 178.64 ng . h/mL. After administration of multiple doses of rosuvastatin 5, 10, and 20 mg, the accumulation ratios were 1.23, 0.95, and 1.23, respectively, indicating minimal accumulation of rosuvastatin. Circulating concentrations of N-desmethyl rosuvastatin and rosuvastatin lactone were well below those of rosuvastatin after administration of single and multiple doses of rosuvastatin. CONCLUSIONS: Increases in C(max), AUC(0-t), C(max,ss), and AUC(ss) were observed with increasing single and multiple doses of rosuvastatin 5, 10, and 20 mg. The increase in exposure with increasing doses was lower than would be expected under conditions of strict proportionality. Rosuvastatin exhibited little accumulation on repeated administration. All rosuvastatin doses were well tolerated in these Chinese subjects.

Matrine determination and pharmacokinetics in human plasma using LC/MS/MS.

A liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed for the determination of matrine in human plasma extracted by isopropanol:ethyl acetate (v/v, 5:95). Rapid chromatographic separation was achieved in the mobile phase composition of 5-mM aqueous ammonium acetate and acetonitrile (v/v, 70:30) with a flow rate of 0.20ml/min. Detection was carried out using positive-ion electrospray tandem mass spectrometry on a Sciex API3000. The method was accurate, specific and sensitive for the analysis of matrine in human plasma in the concentration range of 5-2000ng/ml, when huperzine A was used as internal standard. The method facilitated a clinical pharmacokinetic study after oral administration of a single dose of matrine soft gelatin capsules (100, 200 and 400mg) in a three-period crossover design. Dose-related linear trends were observed for the AUC(0-t) and the C(max) of matrine. The t(1/2) and the T(max) of matrine were independent of the administered doses.

Pharmacokinetics of orally administered single- and multiple-dose olopatadine in healthy Chinese subjects: an open-label study.

BACKGROUND AND OBJECTIVES: Olopatadine is a new selective histamine H(1) receptor antagonist with anti-inflammatory and anti-allergic effects. Its pharmacokinetics and safety have not previously been evaluated in Chinese subjects. The aims of this study were to assess the pharmacokinetics and safety of olopatadine after single- and multiple-dose oral administration in healthy Chinese subjects and to identify any differences in pharmacokinetics between males and females. METHODS: The pharmacokinetic parameters for olopatadine in 12 healthy Chinese subjects (six males and six females) were assessed by determining olopatadine concentrations with a validated liquid chromatography-tandem mass spectrometry method. Safety and tolerability were evaluated by monitoring adverse events, laboratory assay results, vital signs, physical examination findings and 12-lead ECG results. RESULTS: The pharmacokinetic parameters (mean +/- SD) for olopatadine following a single dose were: maximum plasma concentration (C(max)) 69.98 +/-20.87 ng/mL, time to reach C(max) (t(max)) 1.02 +/- 0.34 h, elimination half-life (t1/2) 5.87 +/- 4.24 h, area under the plasma-concentration curve (AUC) from time zero to the time of last quantifiable concentration (AUC(last)) 266.00 +/- 143.95 ng.h/mL, AUC from time zero extrapolated to infinity (AUC(infinity)) 283.46 +/- 152.96 ng.h/mL, apparent oral clearance (CL/F) 23.45 +/- 12.59 L/h and apparent volume of distribution after oral administration (V(d)/F) 133.83 +/- 43.07 L. The pharmacokinetic parameters of olopatadine after multiple doses were similar to those after a single dose. In both studies, significantly higher AUC(last), AUC(infinity) and C(max), longer t1/2 (single-dose only) and lower CL/F were observed in female subjects compared with male subjects after both single and multiple dosing. No serious adverse events occurred. CONCLUSION: Olopatadine was shown to be safe and well tolerated in healthy Chinese subjects. There were no changes in absorption and elimination of olopatadine following multiple doses and no accumulation was found. Possible sex-related differences in absorption and elimination of olopatadine were observed.

Simultaneous determination of desloratadine and its active metabolite 3-hydroxydesloratadine in human plasma by LC/MS/MS and its application to pharmacokinetics and bioequivalence.

A rapid and simple liquid chromatographic-tandem mass spectrometric (LC/MS/MS) method was developed and validated for the simultaneous determination of desloratadine and its active metabolite 3-hydroxydesloratadine concentrations in human plasma. After liquid-liquid extraction with ethyl ether for sample preparation, the chromatographic separation was achieved on a CAPCELL PAK C18 column (50 mm x 2.0mm, 5 microm, Shiseido). [(2)H(4)]desloratadine and [(2)H(4)]3-OH desloratadine were used as internal standards. A mobile phase consisted of 5mM ammonium formate in water, methanol and acetonitrile (50:30:20). Detection was by positive ion electrospray tandem mass spectrometry on a Sciex API3000. A quadratic regression (weighted 1/concentration) gave the best fit for calibration curves over the concentration range 0.05-10 ng/mL for both desloratadine and 3-OH desloratadine. The method was shown to be accurate, rapid and sufficiently sensitive to be successfully applied to a pharmacokinetic and bioequivalent study.

Determination of eprosartan in human plasma and urine by LC/MS/MS.

A protein precipitation, liquid chromatography/tandem mass spectrometry (LC/MS/MS) method has been developed and validated for the determination of eprosartan in human plasma and urine. The solvent system also served as a protein precipitation reagent. The chromatographic separation was achieved on a CAPCELL PAK C18 column (50 mmx2.0 mm, 5 microm, Shiseido). A mobile phase was consisted of 0.5% formic acid in water and 0.5% formic acid in acetonitrile (72:28). Detection was by positive ion electrospray tandem mass spectrometry on a Sciex API3000. The standard curves, which ranged from 5 to 2000 ng/mL in human plasma and from 0.25 to 50 microg/mL in urine, were fitted to a 1/x weighted quadratic regression model. The method proved to be accurate, specific and sensitive enough to be successfully applied to a pharmacokinetic study.

A sensitive assay for simultaneous determination of plasma concentrations of valganciclovir and its active metabolite ganciclovir by LC/MS/MS.

A protein precipitation, liquid chromatography/tandem mass spectrometry (LC/MS/MS) method has been developed and validated for the simultaneous determination of valganciclovir and its active metabolite ganciclovir in human plasma. The solvent system also served as a protein precipitation reagent. The chromatographic separation was achieved on an Aquasil C18 column (50 mm x 2.1mm, 5 microm). A linear gradient mobile phase between 0.02% formic acid and methanol was used. Detection was by positive ion electrospray tandem mass spectrometry on a Sciex API3000. The standard curves, which ranged from 4 to 512 ng/mL for valganciclovir and from 0.1 to 12.8 microg/mL for ganciclovir, were fitted to a 1/x weighted quadratic regression model. The method was proved to be accurate, specific and sensitive enough and was successfully applied to a pharmacokinetic study.