Hongzhong Liu

Impact of age and gender on the pharmacokinetics of gemtuzumab ozogamicin.

Study Objective. To determine the pharmacokinetic parameters of the components of gemtuzumab ozogamicin and to assess the possible influence of age and gender on the values.

Determination of cinacalcet hydrochloride in human plasma by liquid chromatography–tandem mass spectrometry

A sensitive and selective high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed to determine the cinacalcet hydrochloride in human plasma. The analyte was extracted from plasma samples using a 96-well plate automatic solid-phase extraction (SPE) device and chromatographed on an Inertsil SIL-150 (2.1 mm × 50 mm, i.d. 5 μm) column using acetonitrile-water-formic acid (90:10:1) as the mobile phase with an isocratic flow rate of 0.35 mL/min. The detection was performed on a triple quadrupole tandem mass spectrometer in multiple reaction monitoring (MRM) mode using positive electrospray ionization (ESI). The method was validated over the concentration range of 0.1-25 ng/mL. The indicators of inter- and intra-day precision (RSD%) were all within 15.1%, and the accuracy (RE%) was within ± 15%. The lower limit of quantitation (LLOQ) was 0.1 ng/mL. The average extraction recovery was 51.7%, and the detection was not affected by the matrix. The method was successfully applied to a pharmacokinetic study of cinacalcet hydrochloride in healthy Chinese volunteers.

Pharmacokinetics of vorapaxar and its metabolite following oral administration in healthy Chinese and American subjects.

AIM Vorapaxar is a proteaseactivated receptor (PAR)-1 antagonist being developed for the prevention and treatment of thrombotic vascular events. To evaluate race/ethnic differences between Caucasians and Chinese in the pharmacokinetics of vorapaxar and its active metabolite SCH 2046273 (M20) or in the metabolite/parent ratio, we conducted a cross-study comparison on pharmacokinetic data of vorapaxar and M20 obtained from two similarly designed studies: one in healthy Chinese subjects and the other in a healthy Western (United States, [U.S.]) population. METHODS The pharmacokinetic profiles of vorapaxar and M20 were characterized using open label, two treatment parallel group designs in men and women aged 18 - 45 years. Vorapaxar was administered orally as a single dose of 40 mg in Chinese subjects (n = 14) or 120 mg in U.S. subjects (n = 14), or 2.5 mg QD for 6 weeks in both studies (Chinese, n = 14; U.S., n = 23). RESULTS Vorapaxar was rapidly absorbed in both Chinese and U.S. subjects. Vorapaxar and M20 had similar elimination half-lives. The range of metabolite/parent ratios after single dose or daily administration was largely overlapped in Chinese and U.S. subjects. Steady state was attained by day 21 for vorapaxar and M20 in both race/ethnic groups. The accumulation ratios for vorapaxar and M20 during daily administration were similar in Chinese and U.S. subjects. Vorapaxar was well-tolerated in Chinese and U.S. subjects. CONCLUSION The pharmacokinetic profiles of vorapaxar and M20 and the metabolite/parent ratios in healthy Chinese were generally comparable to those in a healthy Western population.

Pharmacokinetic and Pharmacodynamic Properties of Cinacalcet (KRN1493) in Chinese Healthy Volunteers: A Randomized, Open-label, Single Ascending-dose and Multiple-dose, Parallel-group Study.

PURPOSE The aim of this study was to assess the pharmacokinetic (PK) and pharmacodynamic (PD) properties and safety of single and multiple doses of cinacalcet in Chinese healthy volunteers (HVs) for the purposes of a New Drug Application package for the Chinese Food and Drug Administration. METHODS In this randomized, open-label, single ascending-dose and multiple-dose, parallel-group study, 42 Chinese HVs were randomized to receive a single oral dose of 25, 50, or 100 mg of cinacalcet and multiple doses of 50 mg of cinacalcet once daily for 7 days. Plasma cinacalcet concentrations were analyzed by HPLC-MS/MS. The PK parameters were assessed with noncompartmental analysis. Plasma intact parathyroid hormone, serum calcium, and phosphorus concentrations were measured for PD evaluation. The safety profile was also assessed. Adverse events (AEs) were noted during the study. FINDINGS Of the 42 randomized HVs, 41 completed the study per protocol; 1 prematurely discontinued the study because of AEs. Cinacalcet has nonlinear PK properties over a dose range of 25 to 100 mg after a single dose. Mean (SD) Cmax values were 7.68 (4.25), 17 (6.33), and 31.3 (16.42) ng/mL with single doses of 25, 50, and 100 mg of cinacalcet, respectively. Mean (SD) AUC0- last values were 58.4 (25.38), 187 (70.7), and 367 (180.03) hr∙ng/mL with single doses of 25, 50, and 100 mg of cinacalcet, respectively. Steady state was attained within 7 doses of successive daily administration of 50 mg of cinacalcet. At steady state, the mean (SD) Cmax and AUC0-last values were 20.6 (9.63) ng/mL and 297 (146.15) ng∙h/mL. The accumulation ratios of Cmax and AUC (AUCτ/AUC0-24) were 1.21 and 1.32. Plasma intact parathyroid hormone and serum calcium concentrations had similar patterns, both decreased after administration of cinacalcet, whether after single dose or multiple doses. A total of 52 AEs were reported in 20 HVs (47.6%). The most frequently reported AEs after single-dose and multiple-dose cinacalcet administration were hypocalcemia, numbness, dizziness, and muscle soreness. No serious AEs were reported. IMPLICATIONS Cinacalcet was well tolerated and effective after administration of a single oral dose up to 100 mg and multiple doses of 50 mg of cinacalcet once daily for 7 days. Cinacalcet has nonlinear PK properties over a dose range of 25 to 100 mg after a single dose. PK profiles after multiple doses were similar to those after a single dose with no accumulation. Cinacalcet had similar PK and safety profiles between Chinese and Western HVs at the same dose levels.

Simultaneous determination of imigliptin and its three metabolites in human plasma and urine by liquid chromatography coupled to tandem mass spectrometry.

A specific and sensitive method was firstly developed using high performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) to simultaneously quantify imigliptin (KBP-3853) and its three metabolites (KBP-3926, KBP-3902, KBP-5493) in human plasma and urine. Solid-phase extraction (SPE) and direct dilution were used to extract imigliptin and its three metabolites from plasma and urine, respectively. The extracts were injected onto a SymmetryShield RP8 column with a gradient elution of acetonitrile and water containing 5mM ammonium acetate (pH 7). Ionization of KBP-3853, KBP-3926, KBP-3902, KBP-5493, and XZP-3244 (internal standard, IS) was performed using an electrospray ionization (ESI) source in positive mode and detection was carried out with multiple reaction monitoring (MRM) mode. The lower limits of quantitation (LLOQ) of KBP-3853/KBP-3926/KBP-3902/KBP-5493 in human plasma and urine were 0.500/0.500/0.500/0.500ng/mL and 20.0/20.0/10.0/10.0ng/mL, respectively. Inter- and intra-batch precision of imigliptin and its three metabolites were less than 15% and the accuracy was within 85-115% for both plasma and urine. The extraction recoveries of all analytes at three concentration levels were consistent. The specificity, matrix effect, linearity and stabilities under various conditions were validated for imigliptin and its three metabolites in human plasma and urine. In conclusion, the validation results showed that this method was robust, specific, and sensitive and it can successfully fulfill the requirement of clinical pharmacokinetic study of imigliptin hydrochloride in Chinese healthy subjects.

Pharmacokinetics and Safety of Subcutaneous Pasireotide and Intramuscular Pasireotide Long-acting Release in Chinese Male Healthy Volunteers: A Phase I, Single-center, Open-label, Randomized Study

PURPOSE The purpose of this study was to assess the pharmacokinetic (PK) properties and safety of single and multiple doses of subcutaneous (SC) pasireotide and a single-dose intramuscular (IM) long-acting release (LAR) formulation of pasireotide in Chinese healthy volunteers (HVs) versus the PK properties in Western HVs (pooled from previous PK studies). METHODS In this phase I, single-center, open-label study, 45 Chinese male HVs were evenly randomized to 1 to 9 treatment sequences: each volunteer received a single dose of 300, 600, or 900 μg of pasireotide SC on day 1, followed by administration of the same dose BID from day 15 to the morning of day 19, and then a single IM dose of 20, 40, or 60 mg of pasireotide LAR on day 33. The PK parameters were assessed with noncompartmental analysis. Statistical comparison of PK parameters, including AUC, Cmax, and CL/F from both formulations, was made for Chinese versus Western male HVs. The safety profile was also assessed. Metabolic parameters, including blood glucose, insulin, and glucagon, and measures that reflect the effects of pasireotide LAR on relatively long-term glucose control, lipid metabolism, and systemic concentrations of pancreatic enzymes and thyrotropin were evaluated. FINDINGS Of the 45 randomized HVs, 42 completed the study per protocol, 1 withdrew his informed consent for personal reasons, and 2 prematurely discontinued the study because of adverse events (AEs). Concentration-time and safety profiles of both formulations were similar to those reported in Western HVs. Mean geometric mean ratios (GMRs) of Chinese versus Western HVs ranged from 0.79 to 1.42. For most primary PK parameters, 90% CIs for GMRs were within a predefined ethnic insensitivity interval (90% CI, 0.70-1.43). After considering age and weight as covariates in the statistical model, the GMRs and 90% CIs for other PK parameters were within the predefined interval (Cmax in single-dose SC administration) or significantly decreased (Cmin,ss in multiple BID SC doses and first peak Cmax in the single-dose LAR formulation). No serious AEs were reported. Both formulations were well tolerated; pasireotide SC caused transient changes in glucose metabolism. Owing to the differential binding affinity to the somatostatin receptor subtypes, pasireotide LAR elicited a concentration-dependent increase of fasting blood glucose, substantial reduction in triglyceride, and a mild decrease in cholesterol. The most frequently reported AEs after single-dose and multiple-dose pasireotide SC were injection site reaction, nausea, dizziness, and diarrhea; most HVs developed diarrhea with single-dose pasireotide LAR. IMPLICATIONS The pasireotide formulations had similar PK and safety profiles between Chinese and Western male HVs. Thus, no ethnic sensitivity was found for pasireotide SC or LAR.

Determination of LBPT in human plasma by high performance liquid chromatography–tandem mass spectrometry

A rapid and selective HPLC-MS/MS method was developed for the determination of LBPT in human plasma. The analyte was extracted from plasma samples by solid-phase extraction and then chromatographed on a C18 analytical column. The mobile phase consisted of acetonitrile-10mM ammonium formate in 0.1% formic acid (30:70, v/v) and the flow rate was 0.2 mL/min. The detection was performed on a triple quadrupole tandem mass spectrometer in multiple reactions monitoring (MRM) mode using positive electrospray ionization (ESI). The method was validated over the concentration range of 0.2-100 ng/mL. Inter- and intra-day precision (RSD %) were less than 9.2% and the accuracy (RE %) ranged from 0 to 11.0%. The lower limit of quantitation (LLOQ) was 0.2 ng/mL. The extraction recovery was on average 75% and the detection was not affected by the matrix. The method was successfully applied to the pharmacokinetic study of LBPT in healthy Chinese subjects.

A single and multiple dose study to investigate the pharmacokinetics of a prolonged release formulation of ropinirole in healthy Chinese subjects

An open‐label, single, and 7‐day multiple dose study was conducted to investigate the pharmacokinetics, safety and tolerability of a prolonged release formulation of ropinirole 2 mg in healthy Chinese male (n = 12) and female (n = 12) subjects. After single doses, median tmax was 8 hours and mean t12 was 5.26 hours. After 7 days dosing, median tmax was 6 hours ( t12 not determined). Systemic exposure, AUC and Cmax, following multiple and single dosing was similar (mean AUC(0–τ) (h ng/mL): 23.84 vs. AUC(0–∞): 22.13; Cmax (ng/mL) 1.48 vs. 1.21, respectively). Systemic exposure was higher in females than males following single doses (mean AUC(0–24) (h ng/mL): 21.45 vs. 15.48; P = 0.009; Cmax (ng/mL): 1.40 vs. 0.99; P = 0.014, respectively), but similar at steady state (mean AUC(0–τ) (h ng/mL): 24.96 vs. 22.62; Cmax (ng/mL): 1.56 vs. 1.39, respectively). Estimated accumulation ratio was 1.29 (90% CI: 1.11, 1.51). Ropinirole did not display time‐dependent pharmacokinetics (estimated steady state ratio: 1.09; 90% CI: 0.93, 1.27). The most common adverse events included dizziness and oral ulcer. In conclusion, Chinese subjects displayed predictable absorption, exposure and elimination following the prolonged release formulation of ropinirole 2 mg. The safety findings are consistent with the previously established safety profile for ropinirole.

Simultaneous determination of TPN729 and its five metabolites in human plasma and urine by liquid chromatography coupled to tandem mass spectrometry

HighlightsTPN729MA is a novel PDE5 inhibitor proposed to treat erectile dysfunction.TPN729, its four metabolites were successfully determined in plasma and urine by LC–MS/MS method.The method was proved to be a robust, accurate and specified method. ABSTRACT A specific and sensitive method was firstly developed using high performance liquid chromatography coupled with tandem mass spectrometry (HPLC–MS/MS) to simultaneously quantify TPN729 and its metabolites (TPN729‐D1, TPN729‐D2, TPN729M15‐3 and TPN729M3) in human plasma and (TPN729‐D1, TPN729‐D2, TPN729M15‐3 and TPN729M14) in human urine. Protein precipitation and direct dilution were used to extract TPN729 and its metabolites from plasma and urine, respectively. Ionization of TPN729, TPN729‐D1, TPN729‐D2, TPN729M15‐3, TPN729M3, TPN729M14 and sildenafil (internal standard, IS) was performed using an electrospray ionization (ESI) source in positive mode and detection was carried out with multiple reaction monitoring (MRM) mode. This assay method for TPN729 and its five metabolites has been fully validated in terms of sensitivity, linearity, lower limit of quantification (LLOQ), precision, accuracy, stability, matrix effect and recovery. The LLOQ of TPN729/TPN729‐D1/TPN729‐D2/TPN729M15‐3/TPN729M3 in human plasma and TPN729/TPN729‐D1/TPN729‐D2/TPN729M15‐3/TPN729M14 in human urine were 0.200/0.500/2.00/0.500/1.00 ng/mL and 4.00/2.50/10.0/2.50/1.00 ng/mL, respectively. Inter‐ and intra‐batch precision of TPN729 and its metabolites were less than 15% and the accuracy was within ±15% for both plasma and urine. The extraction recoveries of all analytes at three concentration levels were consistent. In conclusion, the validation results showed that this method was robust, specific, and sensitive and it can successfully fulfill the requirement of clinical pharmacokinetic study of TPN729 in Chinese healthy subjects.

Metabolites characterization of a novel DPP-4 inhibitor, imigliptin in humans and rats using ultra-high performance liquid chromatography coupled with synapt high-resolution mass spectrometry

HIGHLIGHTSImigliptin was a novel DPP‐4 inhibitor proposed to treat type 2 diabetes mellitus.Metabolism of imigliptin in humans and rats was first investigated using UHPLC/Q‐TOF HRMS method.A total of 11 metabolites were detected and identified.The mainly metabolic positions of imigliptin were N‐acetylated and oxidation of piperidine. ABSTRACT Imigliptin has been reported as a novel dipeptidyl‐peptidase‐IV (DPP‐4) inhibitor to treat type 2 Diabetes Mellitus (T2DM), and is currently being tested in clinical trials. In the first human clinical study, imigliptin was well tolerated and proved to be a potent DPP‐4 inhibitor. Considering its potential therapeutic benefits and promising future, it is of great importance to study the metabolite profiles in the early stage of drug development. In the present study, a robust and reliable analytical method based on the ultra‐high performance liquid chromatography/quadrupole time‐of‐flight mass spectrometry (UHPLC/Q‐TOF MS) method combined with MassLynx software was established to investigate the characterization of metabolites of imigliptin in human and rat plasma, urine and feces after oral administration. As a result, a total of 9 metabolites were identified in humans, including 6, 9 and 8 metabolites in human plasma, urine, and feces, respectively. A total of 11 metabolites were identified in rats, including 7, 10 and 8 metabolites in rat plasma, urine, and feces, respectively. In addition, 6 of the metabolites detected in humans and rats were phase I metabolites, including demethylation, carboxylation, hydroxylation and dehydrogenation metabolites, and 5 of the metabolites were phase II metabolites, including acetylation and glucuronidation. There was no human metabolite detected compared to those in rats. The major metabolites detected in human plasma (M1 and M2) were products resulting from acetylation, and hydroxylation followed by dehydrogenation. M1 was the major metabolite in rat plasma. M2 and the parent drug were the major drug‐related substances in human urine. The parent drug was the major drug‐related substances in rat urine. M2, M5 (hydroxylation product) and M6 (2×hydroxylation and acetylation product) were the predominant metabolites in human feces. M2 and M5 were the major metabolites in rat feces. In addition, renal clearance was the major route of excretion for imigliptin.