Pharmacokinetic and pharmacodynamic evaluation study of etomidate: a randomized, open-label, 2-period crossover study in healthy Chinese subjects.

Etomidate is a sedative and hypnotic drug through intravenous administration that act on the central nervous system through GABA (Gamma-Amino Butyric Acid) receptors, which is widely used in anesthesia induction and maintenance and long-term sedation in severe patients. The study aimed to evaluate the pharmacokinetic and pharmacodynamic properties of two etomidate fat emulsions after administration through the intravenous infusion pump in healthy Chinese subjects. A randomized, open-label, 2-period crossover study was performed in 52 healthy subjects. The wash-out period was 7 days. Blood samples and pharmacodynamic index values were collected at the specified time points. Etomidate concentrations were measured using validated liquid chromatography-tandem mass spectrometry. Pharmacokinetic parameters were analyzed using a non-compartment model method. Pharmacodynamic parameters were calculated using pharmacodynamic index values. The study also evaluated the safety of the etomidate. Both the pharmacokinetic parameters and pharmacodynamic parameters result of the test and reference formulation were very similar. The 90% confidence intervals (CI) of the geometric least-squares mean (GLSM) ratios of the test to reference formulation were 91.33-104.96% for the maximum plasma concentration (Cmax), 97.21-102.03% for the area under the plasma concentration time curve from time 0 to the time of the last measurable concentration (AUC0-t), and 97.22-102.33% for the area under the plasma concentration time curve from time 0 to infinity (AUC0-∞). Meanwhile, the 90% CI of the GLSM ratios of the test to reference formulation were 102.28-110.69% for the minimal BIS value (BISmin), 99.23-101.17% for the area under the BIS time curve from time 0-60 min after administration (BISAUC0-60 min), respectively. The 90% CI of these pharmacokinetic and pharmacodynamic parameters all fall in the accepted bioequivalence range of 80.00-125.00%. No serious adverse events occurred during the study. This study has shown that the etomidate fat emulsion test and reference formulation had similar pharmacokinetic and pharmacodynamic characteristics in vivo. The two formulations exhibited good safety and well-tolerance.Clinical trials registration number: http://www.chinadrugtrials.org.cn/index.html . # CTR20191836.

Corrigendum: Pharmacokinetics and bioequivalence study of esomeprazole magnesium enteric-coated tablets 20 mg in healthy Chinese subjects under fasting and fed conditions.

[This corrects the article DOI: 10.3389/fphar.2023.1169103.].

Pharmacokinetics and bioequivalence study of esomeprazole magnesium enteric-coated tablets 20 mg in healthy Chinese subjects under fasting and fed conditions.

Objective: The main purpose of this study was to evaluate the pharmacokinetics, bioequivalence, and safety properties between a new generic and a brand reference formulation of esomeprazole enteric-coated tablets 20 mg in healthy Chinese subjects under fasting and fed conditions. Methods: The fasting study was an open-label, randomized, two-period crossover study conducted in 32 healthy Chinese volunteers, and the fed study was a four-period crossover study conducted in 40 healthy Chinese volunteers. Blood samples were collected at the specified time points and determined to obtain the plasma concentrations of esomeprazole. The primary pharmacokinetic parameters were calculated using the non-compartment method. Bioequivalence was analyzed by the geometric mean ratios (GMRs) of the two formulations and the corresponding 90% confidence intervals (CIs). The safety of the two formulations was assessed. Results: The fasting and fed study showed that the pharmacokinetics of the two formulations was similar. Under the fasting condition, the 90% CIs of GMRs of the test-to-reference formulation were 87.92%-104.36% for Cmax, 87.82%-101.45% for AUC0-t, and 87.99%-101.54% for AUC0-∞; under the fed condition, the 90% CIs of GMRs of the test-to-reference formulation were 80.53%-94.95% for Cmax, 87.46%-97.26% for AUC0-t, and 87.46%-97.16% for AUC0-∞. The 90% CIs of GMRs fall within the bioequivalence range of 80.00%-125.00%. The two formulations had good safety and were well-tolerated, and no serious adverse events occurred. Conclusion: According to relevant regulatory standards, esomeprazole enteric-coated generic and reference products exhibited bioequivalence and good safety in healthy Chinese subjects. Clinical Trials Registration: http://www.chinadrugtrials.org.cn/index.html, identifier CTR20171347 and CTR20171484.

The effect of food on the pharmacokinetics of WXFL10203614, a potential selective JAK1 inhibitor, in healthy Chinese subjects.

Objective: This study was performed to investigate the effect of food on the pharmacokinetics (PK) of WXFL10203614 in healthy Chinese subjects. Methods: This was a randomized, open-label, single-dose, two-treatment (fed vs fasted), two-period, two-sequence, crossover study. 14 eligible subjects were averagely randomized into 2 sequences and then received 10 mg WXFL10203614 under fasted or fed condition. In each period, the blood samples were collected from 0 h (pre-dose) and serially up to 72 h post-dose, and plasma concentrations were detected using the high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method. The effect of food on the PK profile and safety of WXFL10203614 were assessed. Results: 70 subjects were screened, and 14 subjects (10 male and 4 female) were enrolled and completed the study. Under the fasted condition, WXFL10203614 was absorbed rapidly with a Tmax of 0.98 h. The absorption rate was slower, Tmax delayed by 2.98 h, and the Cmax decreased by 16.3% when WXFL10203614 administered after the high-fat and high-calorie diet, other PK parameters were not affected. The 90% confidence intervals (CIs) for the ratio (fed/fasted) of geometric means of the Cmax, AUC0-t and AUC0-∞ were 0.73-1.01, 0.90-1.03 and 0.90-1.03, indicating that the high-fat and high-calorie diet might impact the absorption process of WXFL10203614. Although the Cmax was slightly decreased, there was no significant difference in the Cmax under fasted and fed conditions. Thus, it was not considered clinically significant owing to the small magnitude of changes in Cmax. All Treatment-emergent adverse events (TEAEs) were mild and resolved spontaneously without treatment. Conclusion: Food had no clinically relevant effects on drug system exposure of WXFL10203614. It was well tolerated under fasted and fed conditions in healthy Chinese subjects, so WXFL10203614 could be administered orally with or without food. Clinical Trial Registration: http://www.chinadrugtrials.org.cn/index.html, identifier CTR20191636.

Safety, tolerability and pharmacokinetics of WXFL10203614 in healthy Chinese subjects: A randomized, double-blind, placebo-controlled phase â study.

Objective: This study was conducted to investigate the safety, tolerability and pharmacokinetics (PK) of WXFL10203614 after single and multiple oral doses in healthy Chinese subjects. Methods: A single-center, randomized, double-blind, placebo-controlled phase Ⅰ study was performed on healthy Chinese subjects. In the single-dose study, Subjects were randomized into 7 dose levels of WXFL10203614 (1 mg group, n = 2; 2, 5, 10, 17, 25 and 33 mg groups with placebo, 8 subjects per group, 2 of them given placebo). In the multiple-dose study, subjects received 5 or 10 mg WXFL10203614 once daily (QD), 5 mg twice daily (BID) or placebo for 7 consecutive days. Safety, tolerability and PK of WXFL10203614 were all assessed. Results: A total of 592 subjects were screened, 50 subjects were enrolled in the single-dose study and 30 in the multiple-dose study. All adverse events (AEs) were mild or moderate and resolved spontaneously. No Serious Adverse Events (SAEs) or deaths were reported during the study. WXFL10203614 was absorbed rapidly after dosing with Tmax of 0.48-0.98 h, Cmax, AUC0-t and AUC0-∞ were all increased in a dose-related manner over the range of 1-33 mg. Renal excretion was the major route of elimination of WXFL10203614. Steady-state PK parameters (Cmax,ss, AUC0-t,ss and AUC0-∞,ss) were elevated after once-daily administration of 5-10 mg WXFL10203614 and non- and weak drug accumulations were observed, whereas moderate drug accumulation occurred in the 5 mg BID group. Conclusion: WXFL10203614 exhibited good safety, tolerability and favorable PK profiles in healthy Chinese subjects, supporting further clinical development in patients with rheumatoid arthritis. Clinical Trials Registration Number: http://www.chinadrugtrials.org.cn/index.html, #CTR20190069 and CTR20200143.

Safety, Tolerability, and Pharmacokinetic Study of 101BHG-D01 Nasal Spray, a Novel Long-Acting and Selective Cholinergic M Receptor Antagonist, in Healthy Chinese Volunteers: A Randomized, Double-Blind, Placebo-Controlled, Single-Dose Escalation, First-In-Human Study.

BACKGROUND AND OBJECTIVE: 101BHG-D01 nasal spray is the first novel long-acting cholinergic M receptor antagonist under development to treat rhinorrhea in rhinitis. This first-in-human study aimed to evaluate the safety, tolerability, and pharmacokinetics of 101BHG-D01 nasal spray following single intranasal doses in healthy Chinese subjects. METHODS: A randomized, double-blind, placebo-controlled, single-dose escalation study was conducted in healthy Chinese volunteers after intranasal doses of 101BHG-D01 nasal spray or placebo ranging from 40 µg to 960 µg (total of six doses). Blood samples were collected at scheduled time points, and plasma concentrations were determined using a validated high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method. A non-compartmental method was used to calculate the main pharmacokinetic parameters, including the area under the plasma concentration-time curve from time zero to the time of the last measurable concentration (AUC0-t), the area under the plasma concentration-time curve from time zero to infinity (AUC0-∞), the maximum plasma concentration (Cmax), the time to maximum plasma concentration (Tmax), and the elimination half-life (t1/2). Safety was evaluated by monitoring adverse events, laboratory assays, vital signs, physical examinations, 12-lead electrocardiograms (ECGs), anterior rhinoscopy, ophthalmic examination, and ambulatory ECG monitoring. RESULTS: Following single intranasal dosing, 101BHG-D01 was rapidly absorbed with a median Tmax of 0.34-0.50 h and eliminated slowly with a mean t1/2 ranging from 4.29 to 46.76 h for different dose groups. The Cmax and AUC of 101BHG-D01 increased linearly across the examined dose range of 40-960 µg. 101BHG-D01 nasal spray was well tolerated, all AEs were mild, and no serious adverse events occurred during the study. CONCLUSIONS: 101BHG-D01 nasal spray was safe and well tolerated in healthy Chinese subjects when administered intranasally in single escalating doses. The mean Cmax and AUC increased proportionally to the studied dose. The pharmacokinetic, safety, and tolerability profiles of 101BHG-D01 nasal spray indicate that it is a good candidate for further development as a treatment for rhinorrhea in rhinitis.

Comparative Pharmacokinetics, Safety, and Immunogenicity Study of the Prefilled Syringe and Lyophilized Formulation of a Recombinant Human Tumor Necrosis Factor-α Receptor II:lgG Fc Fusion Protein in Healthy Chinese Male Subjects.

This study aimed to compare the pharmacokinetics, safety, and immunogenicity of the prefilled syringe (PFS) with lyophilized (LYO) recombinant human tumor necrosis factor-α receptor II:lgG Fc fusion protein (rhTNFR:Fc) in healthy Chinese male subjects. A single-center, randomized, open-label, 2-period, crossover study was performed in healthy Chinese male subjects. Subjects were randomly assigned into 2 sequences and received a subcutaneous injection of 25 mg rhTNFR:Fc PFS or rhTNFR:Fc LYO (Anbainuo), with a 35-day washout between the 2 periods. Blood samples were collected at specified time intervals, and then serum concentrations of rhTNFR:Fc were analyzed by enzyme-linked immunosorbent assay. The maximum serum concentration, area under the concentration-time curve (AUC) from time 0 to the last quantifiable concentration, and AUC from time 0 to infinity were all calculated and evaluated. Meanwhile, safety and immunogenicity were also assessed. A total of 82 subjects completed the study, and six subjects withdrew for various reasons. The 90%CIs for geometric mean ratios of maximum serum concentration, AUC from time 0 to the last quantifiable concentration, and AUC from time 0 to infinity were all within the equivalence range of 80% to 125%. Safety was comparable between the 2 formulations with low immunogenicity. rhTNFR:Fc PFS exhibited similar pharmacokinetic and safety profiles of rhTNFR:Fc LYO (Anbainuo) in healthy Chinese male subjects.

No apparent pharmacokinetic interactions were found between henagliflozin: A novel sodium-glucose co-transporter 2 inhibitor and glimepiride in healthy Chinese male subjects.

WHAT IS KNOWN AND OBJECTIVE: Henagliflozin is a novel selective sodium-glucose co-transporter 2 (SGLT2) inhibitor with similar inhibitory effect to ertugliflozin. Glimepiride is widely used to treat type 2 diabetes mellitus (T2DM) with few cardiovascular side effects. In the present study, we aimed at evaluating the pharmacokinetic (PK) interactions between henagliflozin and glimepiride. METHODS: An open-label, single-centre, single-arm, 3-period, 3-treatment, self-control study was conducted in twelve healthy Chinese male subjects. During each study period, subjects received a single oral dose of glimepiride 2 mg, multiple oral doses of henagliflozin 10 mg or a combination of the two drugs. Serial blood samples were collected 24 h post-dosing for PK analyses. Finger-tip blood glucose was also tested for safety evaluation. RESULTS AND DISCUSSION: Co-administration of henagliflozin with glimepiride did not affect their plasma PK profiles. For henagliflozin, the 90% confidence intervals for the geometric mean ratio (GMR) for the maximum plasma concentrations at steady-state (Cmax ss ) and the area under the plasma concentration-time curve during a dosing interval at steady-state (AUCτ, ss ) of combination therapy to henagliflozin alone were 1.00 (0.93-1.08) and 1.00 (0.98-1.02), respectively. For glimepiride, the corresponding values of combination therapy to glimepiride alone were 1.00 (0.88-1.13) for maximum plasma concentrations (Cmax ), 0.91 (0.84-0.99) for the area under the plasma concentration-time curve from 0-24 h (AUC0-24h ) and 0.91 (0.83-1.00) for the plasma concentration-time curve from 0 h to infinite (AUC0-inf ), respectively. All values fell within the equivalence range of 0.8-1.25. All monotherapies and combination therapy led to no serious adverse events and were well tolerated. WHAT IS NEW AND CONCLUSION: Multiple doses of henagliflozin did not exert a significant change on glimepiride PK profiles and a single dose of glimepiride had little effect on henagliflozin blood concentration. Thus, henagliflozin can be co-administered with glimepiride without dose adjustment of either drug.

Bioequivalence Study of Palbociclib Capsules in Healthy Chinese Subjects Under Fasting and Fed Conditions.

BACKGROUND AND OBJECTIVE: Palbociclib is an oral small-molecule inhibitor of cyclin-dependent kinase 4/6 used for the treatment of advanced breast cancer. This study compared the pharmacokinetic and safety profiles between a new generic and a branded reference formulation of palbociclib capsules in healthy Chinese subjects under fasting and fed conditions and evaluated the bioequivalence of two palbociclib products to obtain sufficient evidence for the marketing approval of the new generic drug. METHODS: A randomized, open-label, two-period crossover study was conducted in healthy Chinese volunteers under both fasting and fed conditions (30 subjects/condition). Eligible healthy subjects received a single 125-mg dose of the palbociclib test or reference formulation followed by a 14-day washout period. Serial blood samples were collected at scheduled timepoints, and plasma concentrations were determined by a validated high-performance liquid chromatography-tandem mass spectrometry method. A non-compartment method was used to calculate the main pharmacokinetic parameters, including the area under the plasma concentration-time curve (AUC) from time 0 to the time of the last measurable concentration (AUC0-t), the AUC from time 0 to infinity (AUC0-∞), the maximum plasma concentration (Cmax), the time to maximum plasma concentration, and the elimination half-life. The geometric mean ratios and the corresponding 90% confidence intervals of palbociclib were acquired for the bioequivalence analysis. Safety and tolerability were assessed by monitoring adverse events, laboratory assessments, vital signs, physical examinations, and 12-lead electrocardiograms. RESULTS: Under the fasting condition, the pharmacokinetic parameter values of the test formulation were similar to those of the reference formulation. The 90% confidence intervals of geometric mean ratios of the test to reference formulations were 94.35-103.82% for Cmax, 94.79-103.26% for AUC0-t, and 94.82-103.38% for AUC0-∞, which are all within the accepted bioequivalence range of 80.00-125.00%. Meanwhile, under the fed condition, the pharmacokinetic parameter values of the test formulation were also similar to those of the reference formulation. The 90% confidence intervals of geometric mean ratios of the test to reference formulations were 96.65-103.56% for Cmax, 98.06-103.61% for AUC0-t, and 97.88-103.46% for AUC0-∞, which are all within the accepted bioequivalence range of 80.00-125.00%. The test and reference products were well tolerated, and no serious adverse events occurred during the study. CONCLUSIONS: Pharmacokinetic bioequivalence of palbociclib in healthy subjects was established between the palbociclib test formulation and the reference formulation under fasting and fed conditions according to predetermined regulatory criteria. The two formulations were safe and well tolerated.

A Randomized, Double-Blind, Single-Dose Study Comparing the Biosimilarity of HOT-1010 With Bevacizumab (Avastin®) in Chinese Healthy Male Subjects.

Objective: This study was conducted to compare the pharmacokinetics, safety and immunogenicity of HOT-1010 with bevacizumab (Avastin®) in Chinese healthy male subjects. Methods: A single-center, randomized, double-blind, single-dose, parallel trial was performed in 84 Chinese healthy male subjects who randomly (1:1) received a single intravenous infusion of 1 mg/kg HOT-1010 or Avastin® for 90 min and followed up for 85 days. Serum concentrations of bevacizumab were analyzed by enzyme-linked immunosorbent assay. Primary pharmacokinetic parameters, Cmax, AUC0-t and AUC0-∞, were calculated and evaluated the bioequivalence between HOT-1010 and Avastin®, the safety and immunogenicity of investigational drugs were also assessed. Results: A total of 82 subjects completed the study. The 90% Confidence Intervals for geometric mean ratios of Cmax, AUC0-t and AUC0-∞ were 91.81-103.64%, 85.19-95.39% and 85.04-95.36%, which were all within the bioequivalence margin. Treatment-emergent adverse events were reported in 27 (65.9%) subjects in HOT-1010 group and 23 (56.1%) subjects in Avastin® group. Most TEAEs were mild or moderate. No TEAEs, Serious Adverse Events or deaths leading to discontinuation was reported. Subjects were all tested negative for Anti-drug Antibody. Conclusion: HOT-1010 exhibited the similar pharmacokinetics, safety and immunogenicity profiles of bevacizumab (Avastin®) in Chinese healthy male subjects. Clinical Trial Registration: http://www.chinadrugtrials.org.cn/index.html, CTR20181610.

Identification of human uridine diphosphate-glucuronosyltransferase isoforms responsible for the glucuronidation of 10,11-dihydro-10-hydroxy-carbazepine.

OBJECTIVES: To determine the kinetics of the formation of 10,11-dihydro-10-hydroxy-carbazepine (MHD)-O-glucuronide in human liver microsomes (HLMs), human intestine microsomes (HIMs), human kidney microsomes (HKMs) and recombinant human UDP-glucuronosyltransferase (UGTs), and identify the primary UGT isoforms catalyzing the glucuronidation of MHD. METHODS: The kinetics of the glucuronidation of MHD was determined in HLMs, HIMs as well as HKMs. Screening assays with 13 recombinant human UGTs, inhibition studies and correlation analysis were performed to identify the main UGTs involved in the glucuronidation of MHD. KEY FINDINGS: MHD-O-glucuronide was formed in HLMs, HIMs as well as HKMs, HLMs showed the highest intrinsic clearance of MHD. Among 13 recombinant human UGTs, UGT2B7 and UGT1A9 were identified to be the principal UGT isoforms mediating the glucuronidation of MHD, while UGT1A4 played a partial role. In addition, inhibition studies and correlation analysis further confirmed that UGT2B7 and UGT1A9 participated in the formation of MHD-O-glucuronide. CONCLUSIONS: MHD could be metabolized by UGTs in the liver, intestine and kidney, and the hepatic glucuronidation was the critical metabolic pathway. UGT2B7 and UGT1A9 were the primary UGT isoforms mediating the formation of MHD-O-glucuronide in the liver.

Acarbose bioequivalence: Exploration of eligible protocol design.

WHAT IS KNOWN AND OBJECTIVE: Acarbose is a poorly absorbed α-glucosidase inhibitor that acts locally in the intestinal tract. Therefore, the evaluation of its bioequivalence (BE) should be based on pharmacodynamic (PD) rather than pharmacokinetic (PK) endpoints. Currently, there is no consensus on the best method for acarbose BE evaluation. The optimal protocol design regarding dosing time/dose and PD parameters requires further exploration. The aim of the study was to identify an optimum protocol for establishing acarbose BE in healthy Chinese volunteers using PD endpoints. METHODS: Three pilot studies were conducted in healthy Chinese subjects. Study 1 was an open, randomized, two-period crossover study using the reference (R) drug at the dose of 1 × 50 mg. Study 1 aimed to determine appropriate dosing time by comparing the PD effect of acarbose between two administration methods. One method was concomitant administration of sucrose and acarbose, and another method was acarbose administration 10 min before sucrose. Study 2 was an open, randomized, three-period crossover study. Subjects were given the R drug at the dose of 1 × 50 mg, 2 × 50 mg or 3 × 50 mg in a random sequence. The aim of Study 2 was to identify a reasonable dose of acarbose in the BE study. Study 3 was conducted with an open, randomized, three-period crossover design using the test (T) or R drug in an R-T-R sequence at the dose of 2 × 50 mg. Study 3 aimed to compare the BE between the R and T drug and determine intra-individual variation. Twelve subjects were recruited in Study 1, Study 2 and Study 3, respectively, with a one-week washout period. Serum glucose and insulin concentrations were determined after sucrose administration (baseline) and sucrose/acarbose co-administration. RESULTS AND DISCUSSION: In Study 1, no significant differences in PD parameters were found between the two administration methods. The results of Study 2 revealed that the optimal dose was between 1 × 50 mg and 2 × 50 mg. The comparison of PD parameters indicated that the rectifying method could distinguish between different formulations. Study 3 showed that the geometric mean ratios of Cmax, r , AUC0-2 h, r and AUC0-4 h, r were 90.06%, 84.55% and 84.21%, respectively, using the rectifying method. The 90% CIs of Cmax, r were within acceptance limits (80.00%-125.00%), whereas that of AUC0-2 h, r and AUC0-4 h, r were out of the range. The intra-individual variation was approximately 21% for R formulation. Based on the variation, the number of subjects needed to identify formulation differences in the pivotal study would be 55 with 90% power at the 5% level of significance. WHAT IS NEW AND CONCLUSION: The results from our study manifested that a randomized, balanced, two-way crossover design was eligible to evaluate acarbose BE. The appropriate dosing time was concomitant administration of sucrose and acarbose, and the optimal dose was 2 × 50 mg. The rectifying method exhibited preferable sensitivity and applicability in acarbose BE evaluation. A practical sample size of the pivotal study would be 55. These results may help to provide new insights into the protocol design of acarbose BE study.

Rapid and highly sensitive quantification of the anti-tuberculosis agents isoniazid, ethambutol, pyrazinamide, rifampicin and rifabutin in human plasma by UPLC-MS/MS.

With the increased cases of multidrug- or rifampicin-resistant tuberculosis and co-infection with HIV globally, it is difficult to achieve ideal clinical responses because of poor drug absorption and drug-drug interactions. Herein, a bioanalytical UPLC-MS/MS method was developed and validated to quantify five anti-TB agents in human plasma samples for detecting blood drug concentrations to improve therapeutic effects. To overcome the matrix effects, stable isotope labeled analogue of each analyte was used for internal standardization. A simple single-step protein precipitation by acetonitrile was employed for the sample preparation, then the analytes including rifampicin, rifabutin, pyrazinamid, ethambutol, isoniazid and their isotope labeled internal standards (ILISs) were implemented on an HILIC silica column with a gradient mode. The linear range for each analyte was covering the peak drug concentration (Cmax) in the 20 times diluted plasma samples. The coefficient of variation of intra- and inter-day precision was less than 17.0 %, and the accuracy ranged between 91.5 and 110.0 %. The extraction recoveries of all agents were ≥90.2 %, and the matrix effects with internal standard-normalization for all agents were 97.1-110.0 %. The optimal blood sampling time was designed basing on the results of stability validation. This UPLC-MS/MS method with a run time of 3.5 min was successfully applied to routine therapeutic monitoring of the five anti-TB agents in patient plasma.

Pharmacokinetic interaction of finasteride with tamsulosin hydrochloride: an open-label, randomized, 3-period crossover study in healthy Chinese male volunteers.

PURPOSE: The primary aim of this study was to evaluate whether there was clinically significant pharmacokinetic (PK) interaction between finasteride and tamsulosin in healthy Chinese male subjects. METHODS: This was an open-label, randomized, 3-period, crossover study. Subjects received single and multiple doses of 5 mg finasteride alone, single and multiple doses of 0.2 mg tamsulosin hydrochloride sustained-release capsule alone, and single and multiple doses of 5 mg finasteride with 0.2 mg tamsulosin hydrochloride, in an order determined by a computerized randomization schedule. Blood samples were collected up to 48 hours after dosing on study day 1 and up to 24 hours after dosing on study day 9 for determination of plasma concentrations with a validated LC-MS/MS method. Pharmacokinetic parameters were estimated via noncompartmental methods. Tolerability was evaluated by monitoring adverse events, laboratory assays, vital signs, and 12-lead ECG. FINDINGS: Fifteen subjects were enrolled, and 14 completed the study. The geometric mean ratios (GMRs) (90% CIs) of AUC(τ,ss) and C(max,ss) values of finasteride at steady state between coadministration of finasteride and tamsulosin hydrochloride and finasteride alone were 1.14 (1.05-1.23) and 1.06 (0.99-1.14), respectively. The GMRs (90% CIs) for AUC(0-t) and C(max) values of finasteride for a single dose of coadministration of finasteride and tamsulosin hydrochloride and finasteride alone were 1.02 (0.94-1.11) and 1.06 (1.01-1.11), respectively. The GMRs (90% CIs) for AUC(τ,ss) and C(max,ss) values of tamsulosin at steady-state for coadministration of finasteride and tamsulosin hydrochloride and tamsulosin hydrochloride alone were 1.18 (1.05-1.33) and 1.23 (1.06-1.43), respectively. The GMRs (90% CIs) for AUC(0-t) and C(max) values of tamsulosin for a single dose of coadministration of finasteride and tamsulosin hydrochloride and tamsulosin hydrochloride alone were 1.04 (0.97-1.10) and 1.04 (0.98-1.11), respectively. Statistical analyses confirmed that the 90% CIs for these PK parameters were within the predefined not clinically significant PK drug-drug interaction effect boundaries (0.5-2.0) in this study. If comparing the findings with narrower boundaries (0.8-1.25), the conclusion may not be supportive for tamsulosin hydrochloride. During the study, a total of 4 adverse events were reported in 3 subjects including allergic reaction, abnormal findings on an ECG, a slight increase in alanine aminotransferase, and a positive result on glucose urine test. IMPLICATIONS: Both finasteride and tamsulosin hydrochloride were well tolerated. Coadministration of finasteride and tamulosin hydrochloride seems unlikely to lead to a clinically significant PK drug-drug interaction, after a single dose and at steady state.

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.