Pharmacokinetic and Safety Study of Single and Multiple Oral Doses of Safinamide in Healthy Chinese Volunteers

This randomized, parallel-group study evaluated the plasma pharmacokinetic profile of safinamide in 24 healthy Chinese men and women, randomly assigned to receive 50 or 100 mg of safinamide as a single dose, followed, after a 7-day washout, by multiple doses once daily for 7 days. Plasma safinamide was determined up to 96 h after the first single dose (day 1) and the last multiple dose (day 14), and up to 24 h after the first multiple dose (day 8). Following single- and multiple-dose administration, peak concentrations were achieved at a median time of 1.5-2 h. Plasma exposure increased in a dose-proportional manner. After single dose, mean half-life was 23-24 h. Area under the concentration-time curve (AUC) from time zero extrapolated to infinity was only slightly higher than AUC from time zero to the last quantifiable concentration, corresponding for the 2 parameters, respectively, to 12,380 and 11,560 ng • h/mL for the 50 mg and to 22,030 and 20,790 ng • h/mL for the 100-mg dose. AUC in the dosing interval at steady state was 13,150 and 23,100 ng • h/mL for 50 and 100 mg of safinamide. Steady state was reached in 6 days, accumulation was approximately twofold, and the pharmacokinetics were time independent. The plasma safinamide pharmacokinetic profile observed in this study is in line with the published results in both Chinese and non-Asian populations.

A Comparative Pharmacokinetic Study of Fexuprazan 10 mg: Demonstrating Bioequivalence with the Reference Formulation and Evaluating Steady State

Fexuprazan is a potassium-competitive acid blocker approved for treating gastric-acid-related diseases. Although the effectiveness of the recent formulation fexuprazan 10 mg has been demonstrated in Phase 3 clinical trials, data on the pharmacokinetics (PKs) of administering fexuprazan 10 mg twice daily at a 12 h interval are lacking. Moreover, it is imperative to ensure the bioequivalence of the new formulation with the previously approved 40 mg formulation. This study evaluated the pharmacokinetics (PKs) of the single- and multiple-dose oral administration of fexuprazan 10 mg tablets in healthy participants (Part 1) and investigated their bioequivalence with 40 mg tablets (Part 2). Part 1 comprised a single- and multiple-dose, one-sequence, two-period design and eight participants, while Part 2 comprised a single-dose, 2 × 2 crossover design and 24 participants. In Part 1, in Periods 1 and 2, participants received single and multiple doses (twice daily) of fexuprazan 10 mg, respectively. The maximum plasma concentration (Cmax) area under the concentration-time curve from 0 to 12 h (AUC0-12h) of the multiple-dose participants was approximately double that of the single-dose participants. In Part 2, the geometric mean ratios (90% confidence intervals) for Cmax and AUC from zero to the time of the last quantifiable concentration (AUClast) of the use of four fexuprazan 10 mg tablets to those of one fexuprazan 40 mg tablet were 1.0290 (0.9352-1.1321) and 1.0290 (0.9476-1.1174), respectively, meeting the bioequivalence criteria. Favorable PKs were observed after single and multiple administrations of one fexuprazan 10 mg tablet, and four fexuprazan 10 mg tablets were pharmacokinetically equivalent to one fexuprazan 40 mg tablet.

Physiological Responses to Multiple Low-Doses of Bacillus anthracis Spores in the Rabbit Model of Inhalation Anthrax

Bacillus anthracis spores that are re-aerosolized from surface deposits after initial contamination present significant health risks for personnel involved in decontamination. To model repeated exposure to low dose B. anthracis spores, three groups of seven rabbits were challenged with multiple low-doses of B. anthracis spores 5 days a week for 3 weeks. Mortality, body temperature, heart and respiration rates, hematology, C-reactive protein, bacteremia, and serum protective antigen were monitored for 21 days post-exposure after the last of multiple doses. All rabbits exposed to a mean daily dose of 2.91 × 10² colony forming units (CFU) survived and showed minimal physiological changes attributable to exposure. One of seven rabbits receiving a mean daily dose of 1.22 × 10³ CFU died and four of seven receiving a mean daily dose of 1.17 × 10⁴ CFU died. The LD₅₀ was calculated to be 8.1 × 10³ CFU of accumulated dose. Rabbits that succumbed to the higher dose exhibited bacteremia and increases above baseline in heart rate, respiration rate, and body temperature. Two rabbits in the mean daily dose group of 1.17 × 10⁴ CFU exhibited clinical signs of inhalation anthrax yet survived. This study provides a description of lethality, pathophysiology, and pathology in a controlled multiple low-dose inhalation exposure study of B. anthracis in the rabbit model. The data suggest that the accumulated dose is important in survival outcome and that a subset of rabbits may show clinical signs of disease but fully recover without therapeutic intervention

Multiple-Dose Oral Fosfomycin for Treatment of Complicated Urinary Tract Infections in the Outpatient Setting

Background

Few published studies exist to describe the off-label use of multiple-dose fosfomycin for outpatient treatment of complicated urinary tract infections (UTI). The purpose of this study was to characterize the patients, infections, drug susceptibilities, and outcomes of multiple-dose fosfomycin episodes for outpatient UTI treatment.

Methods

This retrospective study evaluated patients who received an outpatient prescription for multiple-dose fosfomycin between July 1999 and June 2018. Multiple-dose fosfomycin prescriptions dispensed for UTI prophylaxis were excluded. The primary outcome was clinical resolution (complete resolution of signs and symptoms) of infection within 30 days. Secondary outcomes included descriptions of antibiotics and cultures before and after treatment, 30-day bacteriologic resolution (posttreatment urine culture <10³ colony-forming units of the original pathogen), and 90-day healthcare utilizations for UTI or pyelonephritis. Data were analyzed using descriptive statistics.

Results

Of 171 multiple-dose fosfomycin treatment episodes, the most common regimen was 1 dose every 3 days, mean duration of 6.1 days. Clinical resolution occurred in 115 of 171 (67.3%) episodes, and bacteriologic resolution occurred in 37 of 76 (48.7%) episodes with posttreatment cultures. Most patients used antibiotics or had urine cultures before treatment (81.9% and 97.7%, respectively). Additional antibiotic use, urine cultures, and healthcare utilizations within 90 days posttreatment occurred in 51.5%, 66.1%, and 24.6% of patients, respectively.

Conclusions

For treating complicated UTI with multiple-dose fosfomycin, clinical resolution occurred in 2 of 3 treatment episodes and bacteriologic resolution occurred in one-half of treatment episodes. Future research is necessary to determine the relative efficacy and safety and optimal dosing regimen, duration, and population for UTI treatment with multiple-dose fosfomycin.

Pharmacokinetics, Pharmacodynamics, and Safety of a Single Escalating Dose and Repeated Doses of Rasagiline Transdermal Patch in Healthy Chinese Subjects

A rasagiline transdermal patch can be used to offer continuous rasagiline to patients with Parkinson's disease who cannot take their usual oral medications. This was the first study to investigate the pharmacokinetics, pharmacodynamics, and safety of the rasagiline transdermal patch in healthy Chinese subjects. Thirty subjects were randomized to 3 groups with 10 subjects in each group. The 10 subjects of group 1 received a single 1-mg dose of rasagiline as a tablet; the 20 subjects of groups 2 and 3 received a single transdermal patch (48-hour patch-on period) containing 1.25 mg and 2.5 mg rasagiline, respectively. After a 2-week washout period, the subjects of group 1 were assigned to receive 1 mg of rasagiline tablets every 24 hours for 7 days, and the subjects of group 2 were assigned to receive 1.25-mg rasagiline transdermal patches (48-hour patch-on period) every 72 hours for 5 time periods. The absorption of rasagiline from the transdermal patch was significantly improved, although the peak plasma concentration was obviously reduced. There was slight accumulation of rasagiline dose after multiple administrations. Inhibition of platelet monoamine oxidase-B (MAO-B) activity was dose dependent. The 80% inhibition maintained for at least 48 hours after multiple-dose administration of 1 mg tablets, and for 72 hours after multiple-dose administration of 1.25 mg/48 h patch. Compared with rasagiline tablets, the transdermal patch had a prolonged duration of 80% inhibition and increased maximal inhibition of MAO-B activity. These characteristics permitted an interval of 3 days of dosing, which was convenient for patients to use.

Erythrocyte Encapsulated Thymidine Phosphorylase for the Treatment of Patients with Mitochondrial Neurogastrointestinal Encephalomyopathy: Study Protocol for a Multi-Centre, Multiple Dose, Open Label Trial

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is an autosomal recessive disorder which primarily affects the gastrointestinal and nervous systems. This disease is caused by mutations in the nuclear TYMP gene, which encodes for thymidine phosphorylase, an enzyme required for the normal metabolism of deoxynucleosides, thymidine, and deoxyuridine. The subsequent elevated systemic concentrations of deoxynucleosides lead to increased intracellular concentrations of their corresponding triphosphates, and ultimately mitochondrial failure due to progressive accumulation of mitochondrial DNA (mtDNA) defects and mtDNA depletion. Currently, there are no treatments for MNGIE where effectiveness has been evidenced in clinical trials. This Phase 2, multi-centre, multiple dose, open label trial without a control will investigate the application of erythrocyte-encapsulated thymidine phosphorylase (EE-TP) as an enzyme replacement therapy for MNGIE. Three EE-TP dose levels are planned with patients receiving the dose level that achieves metabolic correction. The study duration is 31 months, comprising 28 days of screening, 90 days of run-in, 24 months of treatment and 90 days of post-dose follow-up. The primary objectives are to determine the safety, tolerability, pharmacodynamics, and efficacy of multiple doses of EE-TP. The secondary objectives are to assess EE-TP immunogenicity after multiple dose administrations and changes in clinical assessments, and the pharmacodynamics effect of EE-TP on clinical assessments.

A First-in-Human Safety, Tolerability, and Pharmacokinetics Study of Benapenem in Healthy Chinese Volunteers

The objective of this trial was to investigate the safety, tolerability, and pharmacokinetics (PK) of benapenem administered by single or multiple intravenous infusions in healthy Chinese volunteers. The trial was divided into 3 parts. In part A, 94 subjects were enrolled in a double-blind, placebo-controlled, sequential-ascending-single-dose study. The subjects were randomly assigned to groups receiving placebo or benapenem for injection at doses of 62.5, 125, 250, 500, 1,000, 2,000, or 3,000 mg. The effects of intravenous infusion time on the subjects of 250-, 500-, and 1,000-mg groups were explored. In part B, 12 subjects were enrolled in a single-dose PK study under fasting conditions and received 250, 500, or 1,000 mg of benapenem for injection. In part C, 36 subjects were given 250, 500, and 1,000 mg of benapenem for injection once daily for 7 consecutive days. The results showed that benapenem for injection was well tolerated during the studies. The major observed adverse events were mild, and all were resolved spontaneously without any medical intervention. Benapenem was mainly excreted through the kidneys in the form of parent molecule and metabolites. The PK and safety profiles of benapenem in healthy Chinese volunteers support its once-daily dosing in future clinical investigations. (Part A, part B, and part C have been registered at ClinicalTrials.gov under identifiers NCT03588156, NCT03578588, and NCT03570970, respectively.).

Macrofilaricidal Efficacy of Repeated Doses of Ivermectin for the Treatment of River Blindness

Background

Mass drug administration (MDA) with ivermectin is the cornerstone of efforts to eliminate human onchocerciasis by 2020 or 2025. The feasibility of elimination crucially depends on the effects of multiple ivermectin doses on Onchocerca volvulus. A single ivermectin (standard) dose clears the skin-dwelling microfilarial progeny of adult worms (macrofilariae) and temporarily impedes the release of such progeny by female macrofilariae, but a macrofilaricidal effect has been deemed minimal. Multiple doses of ivermectin may cumulatively and permanently reduce the fertility and shorten the lifespan of adult females. However, rigorous quantification of these effects necessitates interrogating longitudinal data on macrofilariae with suitably powerful analytical techniques.

Methods

Using a novel mathematical modeling approach, we analyzed, at an individual participant level, longitudinal data on viability and fertility of female worms from the single most comprehensive multiple-dose clinical trial of ivermectin, comparing 3-monthly with annual treatments administered for 3 years in Cameroon.

Results

Multiple doses of ivermectin have a partial macrofilaricidal and a modest permanent sterilizing effect after 4 or more consecutive treatments, even at routine MDA doses (150 µg/kg) and frequencies (annual). The life expectancy of adult O. volvulus is reduced by approximately 50% and 70% after 3 years of annual or 3-monthly (quarterly) exposures to ivermectin.

Conclusions

Our quantification of macrofilaricidal and sterilizing effects of ivermectin should be incorporated into transmission models to inform onchocerciasis elimination efforts in Africa and residual foci in Latin America. It also provides a framework to assess macrofilaricidal candidate drugs currently under development.

Comparison of Four Methods of Treating Ectopic Pregnancy: A Retrospective Cohort Study

Objective

To compare the results of expectant management, single and multidose methotrexate (MTX) and surgical management of ectopic pregnancy (EP).

Materials and Methods

In this retrospective cohort study, the original files of 233 patients who were treated for EP between May 2009 and December 2016 were analyzed. The patients were assigned to the following groups based on the applied treatment methods: Group 1, expectant management (n = 24), Group 2, single-dose MTX (n = 144), Group 3, multiple-dose MTX (n = 25), and Group 4, surgical intervention (n = 40). The following parameters were recorded and assessed: sociodemographic characteristics, pelvic ultrasonography findings (gestational sac, ectopic mass appearance, positive fetal cardiac activity), serum beta-human chorionic gonadotropin (β-hCG) levels on Day 0, Day 4, and Day 7, and surgical procedures in women that underwent surgical interventions.

Results

The sociodemographic characteristics were similar in all four groups. The percentage of ectopic mass and positive fetal cardiac activity was greater and the diameter of the mass was larger in Group 4 than in the other groups. The β-hCG values on Day 0, Day 4, and Day 7 were statistically different between the groups (p < 0.001). The cutoff value for the β-hCG change for EP resolution was 18% between Day 0 and Day 4 (AUC = 0.726, p < 0.001) and 15% between Day 4 and Day 7 (AUC = 0.874, p < 0.001). The probability of the requirement for an additional dose of MTX was 0.78 (95% CI 0.71 – 0.87; p < 0.001) times lower in patients who had a > 18% decrease in β-hCG levels from Day 0 to Day 4 in comparison to those who had a decrease < 18% from Day 0 to Day 4. The probability of the requirement for an additional dose of MTX was 1.64 (95% CI 1.25 – 2.16; p < 0.001) times greater in patients whose reduction in β-hCG levels from Day 4 to Day 7 was < 15% in comparison to those who had > 15% reduction from Day 4 to Day 7.

Conclusions

Additional dose requirements for patients with EP may be predicted early in the changes in β-hCG levels between Day 0 and Day 4. Further prospective studies are required to elucidate this issue.

Pharmacokinetics and safety of fentanyl sublingual spray and fentanyl citrate intravenous: a multiple ascending dose study in opioid-naïve healthy volunteers

OBJECTIVE

Fentanyl sublingual spray, with its rapid onset for pain relief, may be efficacious in the management of acute or post-operative pain. Because patients in these settings may be opioid-naïve, the study was conducted to determine the safety, tolerability, and pharmacokinetics of multiple dose administration of fentanyl sublingual spray in an opioid-naïve population.

METHODS

Fentanyl sublingual spray (100 mcg, 200 mcg, and 400 mcg) and fentanyl citrate intravenous (IV; 50 mcg) were administered every 0.5, 1.0, 2.0, and 4.0 h for up to three doses per cohort in opioid-naïve subjects (ClinicalTrials.gov identifier: NCT02641340). Eight subjects in each cohort were randomly assigned (six subjects received fentanyl sublingual spray; two subjects received fentanyl citrate IV). Pharmacokinetic and safety-related pharmacodynamic assessments were performed through 24 h post-first dose. Safety assessments were collected through Day 7.

RESULTS

Ninety-six opioid-naïve subjects, aged 20-55 years, with a body mass index of 18.7-31.5 kg/m², participated in the study. Multiple doses of fentanyl sublingual spray (100, 200, and 400 mcg) were generally well tolerated. Hypoxia, observed in the 200-mcg and 400-mcg dose groups, increased with increasing doses and higher dosing frequency, but was readily managed by nasal cannula oxygenation. Overall, nausea increased with increasing doses, and ∼52.6% (10 out of 19) cases of nausea that occurred at the highest dose of 400 mcg were treated with concomitant medication. Overall, the reported adverse events were consistent with the known safety profile of fentanyl.

CONCLUSION

Fentanyl sublingual spray (100 mcg, 200 mg, and 400 mcg) administered every 0.5, 1, 2, and 4 h was generally well tolerated in an opioid-naïve population. The results suggest that doses of 200 mcg or lower may be safe for use in an opioid-naïve population.

Extended-Release Once-Daily Formulation of Tofacitinib: Evaluation of Pharmacokinetics Compared With Immediate-Release Tofacitinib and Impact of Food

Tofacitinib is an oral Janus kinase inhibitor for the treatment of rheumatoid arthritis. An extended‐release (XR) formulation has been designed to provide a once‐daily (QD) dosing option to patients to achieve comparable pharmacokinetic (PK) parameters to the twice‐daily immediate‐release (IR) formulation. We conducted 2 randomized, open‐label, phase 1 studies in healthy volunteers. Study A characterized single‐dose and steady‐state PK of tofacitinib XR 11 mg QD and intended to demonstrate equivalence of exposure under single‐dose and steady‐state conditions to tofacitinib IR 5 mg twice daily. Study B assessed the effect of a high‐fat meal on the bioavailability of tofacitinib from the XR formulation. Safety and tolerability were monitored in both studies. In study A (N = 24), the XR and IR formulations achieved time to maximum plasma concentration at 4 hours and 0.5 hours postdose, respectively; terminal half‐life was 5.9 hours and 3.2 hours, respectively. Area under plasma concentration‐time curve (AUC) and maximum plasma concentration (C_max) after single‐ and multiple‐dose administration were equivalent between the XR and IR formulations. In study B (N = 24), no difference in AUC was observed for fed vs fasted conditions. C_max increased by 27% under the fed state. On repeat administration, negligible accumulation (<20%) of systemic exposures was observed for both formulations. Steady state was achieved within 48 hours of dosing with the XR formulation. Tofacitinib administration as an XR or IR formulation was generally well tolerated in these studies.

Pharmacokinetics and Safety of Brexpiprazole Following Multiple-Dose Administration to Japanese Patients With Schizophrenia

Brexpiprazole is currently approved in the United States for the treatment of schizophrenia and as adjunctive treatment of major depressive disorder. In Canada, it is approved for the treatment of schizophrenia. This study evaluated the pharmacokinetics (PK) and safety of brexpiprazole in Japanese patients with schizophrenia. This phase 1 study comprised a 14‐day multiple‐dose administration of brexpiprazole 1, 4, and 6 mg/day (n = 7, 8, and 6, respectively). Plasma concentrations and PK parameters and the influence of CYP2D6 polymorphisms (intermediate metabolizers [IMs] and extensive metabolizers [EMs]) on PK were evaluated. Adverse events (AEs) were recorded. The C_max and AUC_24h of brexpiprazole and its metabolite, DM‐3411, showed dose‐proportionality. The C_max and AUC_24h of brexpiprazole showed accumulation of about 2.5‐ to 5.5‐fold on day 14, compared with those on day 1. The median t_max and the mean elimination half‐life of brexpiprazole were 4–5 and 52–92 hours, respectively, across all doses on day 14. The C_24h of brexpiprazole reached steady state after day 10 in all dose groups. The dose‐normalized C_max and AUC_24h of brexpiprazole on day 14 were higher in IM patients than in EM patients. AEs were generally mild to moderate, with transient serum prolactin increase being the most common event. No clinically significant changes were observed for other clinical laboratory values. Brexpiprazole was safe and well tolerated in the studied Japanese patients with schizophrenia.

Single dose versus multiple dose of antibiotic prophylaxis in caesarean section: a systematic review and meta-analysis

BACKGROUND

Prophylactic antibiotics are traditionally given as a single dose for caesarean section. However, inconsistent application of recommendations and recent evidence prompted a literature review.

OBJECTIVES

To assess the optimal regimen for antibiotic prophylaxis in caesarean section by comparing single versus multiple doses of the same intervention.

SEARCH STRATEGY

MEDLINE, Web of Knowledge, SCOPUS, CENTRAL and ongoing trials databases were searched. Reference lists were reviewed and international groups contacted.

SELECTION CRITERIA

Randomised controlled trials (RCT) comparing single with multiple dose regimens of the same antibiotic prophylaxis. Quasi-RCT and abstracts were suitable for inclusion.

DATA COLLECTION AND ANALYSIS

Reviewers independently extracted data and assessed quality of evidence. A random-effects model was used and results presented as risk ratio (RR) with 95% confidence intervals (CI).

MAIN RESULTS

Sixteen studies were included, involving 2695 women. Nonsignificant differences were observed between single dose and multiple dose antibiotic prophylaxis in the incidence of postpartum infectious morbidity (RR 0.95, 95% CI 0.75-1.20, I2 = 25%), endometritis (RR 1.03, 95% CI 0.74-1.42, I2 = 0%) and wound infection (RR 1.22, 95% CI 0.72-2.08, I2 = 0%). A trend towards lower risk of urinary tract infection was seen with multiple dose (RR 0.65, 95% CI 0.34-1.24, I2 = 0%).

CONCLUSIONS

There was insufficient evidence to determine whether there is a difference between single and multiple dose regimens in reducing the incidence of infectious morbidity after caesarean section. The quality of evidence was very low and well-designed RCTs are needed.

TWEETABLE ABSTRACT

Insufficient evidence of difference between dosage regimens of antibiotic prophylaxis in caesarean section.

Effects of multiple-dose ponesimod, a selective S1P1 receptor modulator, on lymphocyte subsets in healthy humans

This study investigated the effects of ponesimod, a selective S1P₁ receptor modulator, on T lymphocyte subsets in 16 healthy subjects. Lymphocyte subset proportions and absolute numbers were determined at baseline and on Day 10, after once-daily administration of ponesimod (10 mg, 20 mg, and 40 mg each consecutively for 3 days) or placebo (ratio 3:1). The overall change from baseline in lymphocyte count was -1,292±340×10⁶ cells/L and 275±486×10⁶ cells/L in ponesimod- and placebo-treated subjects, respectively. This included a decrease in both T and B lymphocytes following ponesimod treatment. A decrease in naïve CD4⁺ T cells (CD45RA⁺CCR7⁺) from baseline was observed only after ponesimod treatment (-113±98×10⁶ cells/L, placebo: 0±18×10⁶ cells/L). The number of T-cytotoxic (CD3⁺CD8⁺) and T-helper (CD3⁺CD4⁺) cells was significantly altered following ponesimod treatment compared with placebo. Furthermore, ponesimod treatment resulted in marked decreases in CD4⁺ T-central memory (CD45RA^-CCR7⁺) cells (-437±164×10⁶ cells/L) and CD4⁺ T-effector memory (CD45RA^-CCR7^-) cells (-131±57×10⁶ cells/L). In addition, ponesimod treatment led to a decrease of -228±90×10⁶ cells/L of gut-homing T cells (CLA^-integrin β7⁺). In contrast, when compared with placebo, CD8⁺ T-effector memory and natural killer (NK) cells were not significantly reduced following multiple-dose administration of ponesimod. In summary, ponesimod treatment led to a marked reduction in overall T and B cells. Further investigations revealed that the number of CD4⁺ cells was dramatically reduced, whereas CD8⁺ and NK cells were less affected, allowing the body to preserve critical viral-clearing functions.

Multiple dose pharmacokinetics of inhaled loxapine in subjects on chronic, stable antipsychotic regimens

This randomized, double‐blind, placebo‐controlled, parallel‐group study was to determine the pharmacokinetic characteristics, safety, and tolerability of multiple doses of inhaled loxapine aerosol in subjects on a stable, oral, chronic antipsychotic regimen. Loxapine was delivered by means of a unique thermally generated aerosol comprising drug particles of a size designed for deep lung delivery and absorption. Thirty‐two subjects were randomized 1:1:1:1 to receive inhaled loxapine (total doses of 15, 20, or 30 mg) or inhaled placebo administered in 3 divided doses, given 4 hours apart. Following inhalation, the median T_max was 2 minutes, and concentrations declined to about half C_max approximately 5 minutes later across the 3 dose levels. The dose proportionality across data from this study combined with data from the single‐dose study showed a slope (90%CI) of log AUC_inf versus log dose of 0.818 (0.762–0.875) across the 8 doses (n = 60 subjects) studied, indicating reasonable dose proportionality. The most common adverse events were cough (3 of 32, 9%), sedation (3 of 32, 9%), and dysgeusia (2 of 32, 6%). The inhalation of multiple doses of inhaled loxapine were well tolerated in study subjects and provided a safe, well‐tolerated means for rapidly and reliably achieving therapeutic plasma concentrations of loxapine. ClinicalTrials.gov identifier: NCT00555412

Single- and multiple-dose tolerability and pharmacokinetics of the CRTH2 antagonist setipiprant in healthy male subjects

Chemoattractant receptor-homologous molecule expressed on T helper (Th) 2 cells (CRTH2) is a G-protein-coupled receptor for prostaglandin D2 (PGD2), a key mediator in inflammatory disorders such as asthma and allergic rhinitis. In this study, we investigated the single- and multiple-dose tolerability and pharmacokinetics (PKs) of setipiprant, an orally active, potent, and selective CRTH2 antagonist. This randomized, double-blind, placebo-controlled study was performed in two parts in healthy male subjects. In study Part A, single oral doses of up to 2000 mg setipiprant or placebo were given to sequential groups of eight subjects each. Additionally, the impact of food on the PKs was investigated in one-dose group. In study Part B, two groups of subjects received 500 or 1000 mg setipiprant or placebo b.i.d. during 5.5 days. At regular intervals, tolerability variables and plasma and urine levels of setipiprant were determined. Setipiprant was well tolerated after single- and multiple-dose administration. Headache was the most frequently reported adverse event. No treatment effect on tolerability variables was observed. After single- and multiple-dose administration, setipiprant was rapidly absorbed and followed a biphasic elimination pattern with an elimination half-life between 10 and 18 h. Steady-state conditions were reached after 2-3 days and setipiprant did not accumulate. Exposure to setipiprant was lower in the presence of food. Urinary excretion of unchanged setipiprant did not exceed 7% of the administered dose. In this entry-into-human study, setipiprant showed good tolerability and a favorable PK profile, thus warranting its development in the treatment of inflammatory disorders.

Single- and multiple-dose pharmacokinetics of genistein capsules in healthy chinese subjects: A phase I, randomized, open-label study

BACKGROUND

Genistein capsules are currently being developed to treat osteoporosis in China. Genistein is extracted from the fruit of Sophora japonica Leguminosae.

OBJECTIVE

The objective of this study was to assess the pharmacokinetics of genistein capsules after single and multiple oral doses in healthy Chinese subjects.

METHODS

This was a Phase I, randomized, open-label, single- and multiple- dose study in healthy Chinese adults (aged 19-40 years). In the single-dose study, subjects were randomly assigned in a 1:1:1 ratio to receive genistein 50, 100, or 300 mg (in 50-mg capsules). To assess the effect of food on the pharmacokinetics, subjects in the 50-mg group were equally randomized again into fasting and postprandial (genistein was administered after a high-fat breakfast) groups according to a 2-way cross-over design. A separate equal-sized group of subjects were administered genistein 50 mg on day 1 (single dose), received no treatment on days 2 and 3, and were administered genistein 50 mg QD for 6 days (days 4-9) to obtain a multiple-dose pharmacokinetic profile. Because genistein is converted so rapidly and completely to glucuronidated genistein after administration, plasma concentrations of glucuronidated genistein were determined using a validated high-performance liquid chromatography/ tandem mass spectrometry method. Drug tolerability was assessed by monitoring adverse events (AEs) and laboratory parameters.

RESULTS

The study enrolled 40 healthy subjects (24 men, 16 women; 10 each in the 50-, 100-, and 300-mg single-dose groups and 10 in the multiple-dose group). Three subjects voluntarily withdrew (2 in the 100-mg group and 1 in the 300-mg group) before study drug administration. Thirty-seven subjects (24 men, 13 women) completed the study and were included in the analysis. The mean (SD) values of the single-dose genistein 50-, 100-, and 300-mg groups were as follows: Tmax, 6.0 (2.4), 7.4 (2.4), and 5.6 (1.2) hours, respectively; tl/2, 13.0 (4.0), 12.6 (5.8), and 9.4 (1.1) hours; AUC0-t, 3344 (1635), 8389 (5164), and 9361 (2428) ng/mL · h(-1); and Cmax , 218.7 (68.6), 435.7 (202.1), and 553.4 (152.8) ng/mL. The plasma glucuronidated genistein concentrations were directly proportional to the administered dose over the range of 50 to 100 mg and increased nonproportionately with the 300-mg dose. No statistically significant differences in pharmacokinetic parameters were found in the fasting group compared with the postprandial group. In the multiple-dose group, the mean (SD) steady-state pharmacokinetic parameters on day 9 were similar to those following a single dose of genistein on day 1 (Tmax, 6.0 [1.0] vs 5.9 [1.5] hours, respectively; tl/2, 9.5 [1.5] vs 9.1 [1.5] hours; AUC0-t, 2830 [1541] vs 2078 [1308] ng/mL · h(-1); Cmax, 203.1 [130.9] vs 168.4 [105.7] ng/mL). All AEs were assessed as mild or moderate and resolved without treatment, with the exception of elevated alanine aminotransferase and aspartate aminotransferase activities in one subject that resolved with treatment.

CONCLUSIONS

The pharmacokinetics of glucuronidated genistein appeared to fit the linear-dose range of genistein 50 to 100 mg, but not the 300-mg dose in these healthy Chinese volunteers. Food consumption did not significantly affect the pharmacokinetic properties. No significant differences were observed in the pharmacokinetic parameters after multiple doses of genistein compared with a single dose, suggesting that the drug did not accumulate after multiple doses.

Relevance of UDP-glucuronosyltransferase polymorphisms for drug dosing: A quantitative systematic review

UDP-glucuronosyltransferases (UGT) catalyze the biotransformation of many endobiotics and xenobiotics, and are coded by polymorphic genes. However, knowledge about the effects of these polymorphisms is rarely used for the individualization of drug therapy. Here, we present a quantitative systematic review of clinical studies on the impact of UGT variants on drug metabolism to clarify the potential for genotype-adjusted therapy recommendations. Data on UGT polymorphisms and dose-related pharmacokinetic parameters in man were retrieved by a systematic search in public databases. Mean estimates of pharmacokinetic parameters were extracted for each group of carriers of UGT variants to assess their effect size. Pooled estimates and relative confidence bounds were computed with a random-effects meta-analytic approach whenever multiple studies on the same variant, ethnic group, and substrate were available. Information was retrieved on 30 polymorphic metabolic pathways involving 10 UGT enzymes. For irinotecan and mycophenolic acid a wealth of data was available for assessing the impact of genetic polymorphisms on pharmacokinetics under different dosages, between ethnicities, under comedication, and under toxicity. Evidence for effects of potential clinical relevance exists for 19 drugs, but the data are not sufficient to assess effect size with the precision required to issue dose recommendations. In conclusion, compared to other drug metabolizing enzymes much less systematic research has been conducted on the polymorphisms of UGT enzymes. However, there is evidence of the existence of large monogenetic functional polymorphisms affecting pharmacokinetics and suggesting a potential use of UGT polymorphisms for the individualization of drug therapy.

Pharmacokinetics of dihydrocodeine and its active metabolite after single and multiple oral dosing

AIMS

The pharmacokinetics of dihydrocodeine (DHC) and its active metabolite dihydromorphine (DHM) were assessed after a single oral dose of DHC and after increasing doses of DHC at steady-state. Methods Twelve healthy male volunteers (18-45 years, CYP2D6 extensive metabolizers (EMs), MR<1 took a single oral dose (s.d.) of DHC 60 mg after breakfast. After 60 h DHC 60 mg was administered twice daily for 3 days, the dose was increased to 90 mg twice daily for 3 days, the final dose of 120 mg was administered twice daily for 3 days (multiple dose: m.d.). Blood sampling and urine collection: during 60 h after s.d. and during 12 h after m.d. Results No significant differences in the area under the curve (AUC) of both, DHC and DHM could be detected after a single oral dose of 60 mg DHC (AUC (0,infinity)) and during steady-state doses of 60 mg DHC (AUC(0,12 h)). During increasing steady-state doses of DHC, the data showed a dose linearity of AUC, maximal serum concentration (Cmax ) and minimal steady-state serum levels (Cssmin) of both, DHC and DHM (P<0.0001), point estimates of DHC dose corrected AUCs were well within the bioequivalence range (60 mg: 0.989; 90%CI 0.951-1. 028, 90 mg: 0.997; 90%CI 0.959-1.036, 120 mg: 0.977; 90%CI 0.940-1. 016). O-demethylation from DHC to DHM remained constant within the increasing steady-state doses of DHC in the 12 extensive metabolizers of CYP2D6.

CONCLUSIONS

In the studied dose range (60-120 mg) the pharmacokinetics of DHC and its active metabolite DHM are linear in EMs of CYP2D6.