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Aim: To assess viral clearance, pharmacokinetics, tolerability and symptom evolution following ensovibep administration in symptomatic COVID-19 outpatients., Methods: In this open-label, first-in-patient study a single dose of either 225 mg (n = 6) or 600 mg (n = 6) of ensovibep was administered intravenously in outpatients with mild-to-moderate COVID-19 symptoms. Pharmacokinetic profiles were determined (90-day period). Pharmacodynamic assessments consisted of viral load (qPCR and cultures) and symptom questionnaires. Immunogenicity against ensovibep and SARS-CoV-2-neutralizing activity were determined. Safety and tolerability were assessed throughout a 13-week follow-up., Results: Both doses showed similar pharmacokinetics (first-order) with mean half-lives of 14 (SD 5.0) and 13 days (SD 5.7) for the 225- and 600-mg groups, respectively. Pharmacologically relevant serum concentrations were maintained in all subjects for at least 2 weeks postdose, regardless of possible immunogenicity against ensovibep. Viral load changes from baseline at day 15 were 5.1 (SD 0.86) and 5.3 (SD 2.2) log 10 copies/mL for the 225- and 600-mg doses, respectively. COVID-19 symptom scores decreased from 10.0 (SD 4.1) and 11.3 (SD 4.0) to 1.6 (SD 3.1) and 3.3 (SD 2.4) in the first week for the 225- and 600-mg groups, respectively. No anti-SARS-CoV-2 neutralizing activity was present predose and all patients had SARS-CoV-2 antibodies at day 91. Adverse events were of mild-to-moderate severity, transient and self-limiting., Conclusion: Single-dose intravenous administration of 225 or 600 mg of ensovibep appeared safe and well tolerated in patients with mild-to-moderate COVID-19. Ensovibep showed favourable pharmacokinetics in patients and the pharmacodynamic results warrant further research in a larger phase 2/3 randomized-controlled trail., (© 2022 The Authors. British Journal of Clinical Pharmacology published by John Wiley & Sons Ltd on behalf of British Pharmacological Society.)

Aims: During phase I study conduct, blinded data are reviewed to predict the safety of increasing the dose level. The aim of the present study was to describe the probability that effects are observed in blinded evaluations of data in a simulated phase I study design., Methods: An application was created to simulate blinded pharmacological response curves over time for 6 common safety/efficacy measurements in phase I studies for 1 or 2 cohorts (6 active, 2 placebo per cohort). Effect sizes between 0 and 3 between-measurement standard deviations (SDs) were simulated. Each set of simulated graphs contained the individual response and mean ± SD over time. Reviewers (n = 34) reviewed a median of 100 simulated datasets and indicated whether an effect was present., Results: Increasing effect sizes resulted in a higher chance of the effect being identified by the blinded reviewer. On average, 6% of effect sizes of 0.5 between-measurement SD were correctly identified, increasing to 72% in 3.0 between-measurement SD effect sizes. In contrast, on average 92-95% of simulations with no effect were correctly identified, with little effect of between-measurement variability in single cohort simulations. Adding a dataset of a second cohort at half the simulated dose did not appear to improve the interpretation., Conclusion: Our analysis showed that effect sizes <2× the between-measurement SD of the investigated outcome frequently go unnoticed by blinded reviewers, indicating that the weight given to these blinded analyses in current phase I practice is inappropriate and should be re-evaluated., (© 2022 The Authors. British Journal of Clinical Pharmacology published by John Wiley & Sons Ltd on behalf of British Pharmacological Society.)

Aims: Whereas intravenous administration of Toll-like receptor 4 ligand lipopolysaccharide (LPS) to human volunteers is frequently used in clinical pharmacology studies, systemic use of LPS has practical limitations. We aimed to characterize the intradermal LPS response in healthy volunteers, and as such qualify the method as local inflammation model for clinical pharmacology studies., Methods: Eighteen healthy male volunteers received 2 or 4 intradermal 5 ng LPS injections and 1 saline injection on the forearms. The LPS response was evaluated by noninvasive (perfusion, skin temperature and erythema) and invasive assessments (cellular and cytokine responses) in skin biopsy and blister exudate., Results: LPS elicited a visible response and returned to baseline at 48 hours. Erythema, perfusion and temperature were statistically significant (P < .0001) over a 24-hour time course compared to saline. The protein response was dominated by an acute interleukin (IL)-6, IL-8 and tumour necrosis factor response followed by IL-1β, IL-10 and interferon-γ. The cellular response consisted of an acute neutrophil influx followed by different monocyte subsets and dendritic cells., Discussion: Intradermal LPS administration in humans causes an acute, localized and transient inflammatory reaction that is well-tolerated by healthy volunteers. This may be a valuable inflammation model for evaluating the pharmacological activity of anti-inflammatory investigational compounds in proof of pharmacology studies., (© 2021 The Authors. British Journal of Clinical Pharmacology published by John Wiley & Sons Ltd on behalf of British Pharmacological Society.)

There is a need for antidiabetic agents successfully targeting insulin sensitivity and treating obesity control at the same time. The aim of this first-in-human study was (a) to evaluate safety and tolerability, (b) to evaluate pharmacokinetics and (c) to assess indications of receptor engagement of single ascending doses of KBP-042, a dual amylin and calcitonin receptor agonist (DACRA) that has shown promising preclinical data, with superior activity in terms of typical amylin-induced responses including reduction of food intake, weight loss and gluco-regulatory capacities. A randomised double-blind placebo-controlled single ascending dose study was performed with six dose levels of KBP-042 (5, 7.5, 10, 20, 20 (evening), 40 ug) in healthy male adults. KBP-042 or placebo was administered as a single dose after an overnight fast, followed by a standardized lunch after 4 hours. KBP-042 was associated with dose-dependent complaints of nausea and vomiting, with a lack of tolerability at doses of 20 μg and above. Doses of 5-40 μg KBP-042 behaved according to a linear pharmacokinetic profile. Indications of target receptor engagement were observed at the level of glucose control and lowering of bone resorption, compared to placebo. The results of this study showed that doses up to 40 μg were safe, although tolerability was not present at the highest doses. The study confirmed target receptor engagement at the studied doses., (© 2021 British Pharmacological Society.)

Aims: To evaluate feasibility of intradermal (i.d.) adalimumab administration using hollow microneedles, and to compare a single i.d. dose of adalimumab using a hollow microneedle with a single subcutaneous (s.c.) dose using a conventional needle., Methods: In this single-centre double-blind, placebo-controlled, double-dummy clinical trial in 24 healthy adults we compared 40 mg adalimumab (0.4 mL) administered i.d. using a hollow microneedle with a s.c. dose using a conventional needle. Primary parameters were pain, acceptability and local tolerability; secondary parameters safety, pharmacokinetics and immunogenicity. We explored usability of optical coherence tomography, clinical photography, thermal imaging, and laser speckle contrast imaging to evaluate skin reaction after i.d. injections. In vitro protein analysis was performed to assess compatibility of adalimumab with the hollow microneedle device., Results: While feasible and safe, injection pain of i.d. adalimumab was higher compared to s.c. adalimumab (35.4 vs. 7.9 on a 100-point visual analogue scale). Initial absorption rate and relative bioavailability were higher after i.d. adalimumab (time to maximum plasma concentration = 95 h [47-120]; F rel = 129% [6.46%]) compared to s.c. adalimumab (time to maximum plasma concentration = 120 h [96-221]). Anti-adalimumab antibodies were detected in 50% and 83% of the subjects after i.d. and s.c. adalimumab, respectively. We observed statistically significantly more erythema and skin perfusion after i.d. adalimumab, compared to s.c. adalimumab and placebo injections (P < .0001). Cytokine secretion after whole blood lipopolysaccharide challenge was comparable between administration routes., Conclusions: Intradermal injection of adalimumab using hollowing microneedles was perceived as more painful and less accepted than s.c. administration, but yields a higher relative bioavailability with similar safety and pharmacodynamic effects., (© 2021 The Authors. British Journal of Clinical Pharmacology published by John Wiley & Sons Ltd on behalf of British Pharmacological Society.)

Aim: To investigate the safety, tolerability, pharmacokinetics and pharmacodynamics of the highly selective oral p38alpha/beta mitogen-activated protein (MAP) kinase inhibitor Org 48,775-0 in a first-in-human study., Methods: In the single ascending dosing (SAD) study, an oral dose of Org 48,775-0 (0.3-600 mg) was evaluated in healthy males. In the multiple ascending dosing (MAD) study, levels of 30, 70 and 150 mg were dosed for six consecutive days, twice daily. Both studies were performed in a double-blind, randomized, placebo-controlled, cross-over fashion and evaluated pharmacokinetics, pharmacodynamics (ex vivo inhibition of lipopolysaccharide [LPS]-induced tumor necrosis factor (TNFα) release) and routine clinical and laboratory data. Pharmacokinetic and pharmacodynamic parameters of Org 48,775-0 were compared between healthy males and postmenopausal females, and the effect of a standardized fat meal was evaluated., Results: All adverse events observed in the SAD (16; dizziness and headache, diarrhoea and catheter-related phlebitis) and MAD (43; mainly somnolence, dizziness, headache and nasopharyngitis) cohorts were mild, transient and completely reversible. Pharmacokinetics were linear up to single doses of 400 mg. Median T max ranged from 0.5 to 1.8 hours, geometric mean for T 1/2 from 7.0 to 14.4 hours. Org 48,775-0 doses equal to and greater than 30 mg significantly inhibited LPS-induced TNFα release (42.3%; 95% CI = -65.2, -4.3) compared to placebo. In the MAD study, Org 48,775-0 treatment inhibited LPS-induced TNFα release during the entire steady-state period. Levels of inhibition amounted 30-75% for 30 mg, 53-80% for 70 mg and 77-92% for 150 mg Org 48,775-0., Conclusion: Org 48,775-0 has the capacity to significantly inhibit MAP kinase activity in humans without safety concerns., (© 2020 British Pharmacological Society.)

Aims: Keyhole limpet haemocyanin (KLH) immunization is a clinical model for the evaluation of human antibody responses. The current study evaluated the anti-KLH antibody response after KLH immunization and the delayed-type hypersensitivity response following intradermal KLH administration, using objective imaging techniques., Methods: Healthy male subjects aged 24.5 ± 5.4 years were randomized to intramuscular immunization with 100 μg KLH (n = 12) or placebo (n = 3). Anti-KLH antibody (Ig) M and IgG titres were determined before and every 7 days after KLH immunization for a total of 28 days. Twenty-one days after the immunization, all subjects received 1 μg KLH intradermally. Prior to and 2 days after intradermal KLH administration, skin blood perfusion, erythema and oedema were quantified using noninvasive imaging tools. Repeated measures ANCOVAs were used to analyse data., Results: Anti-KLH IgM and IgG titres increased after KLH immunization compared to placebo (estimated difference [ED]: 37%, 95% confidence interval [CI]: 19-51% and ED: 68%, 95% CI: 56-76% respectively). Upon intradermal KLH administration an increase in skin blood perfusion (ED: 10.9 arbitrary units (AU), 95% CI: 1.4-20.4 AU) and erythema (ED: 0.3 AU, 95% CI: 0.1-0.5 AU) was observed in KLH-immunized subjects compared to placebo., Conclusion: KLH immunization followed by intradermal KLH administration resulted in increased anti-KLH IgM and IgG titres and a delayed-type hypersensitivity response quantified by an increase in skin blood perfusion and erythema. Using noninvasive imaging tools the KLH model has the potential to serve as an objective tool to study the pharmacodynamics of T-cell-directed immunomodulatory drugs., (© 2020 The Authors. British Journal of Clinical Pharmacology published by John Wiley & Sons Ltd.)

Aims: To assess safety and tolerability and explore pharmacodynamics and efficacy of omiganan in external anogenital warts (AGW) and vulvar high-grade squamous intraepithelial lesions (HSIL)., Methods: Two randomized controlled trials in patients with external AGW and vulvar HSIL were conducted. Patients received topical omiganan 2.5% or placebo gel once daily for 12 weeks with a follow-up of 12 weeks. Safety and tolerability were monitored and pharmacodynamics and clinical efficacy of omiganan were assessed by analysing lesion count, size and viral load. Self-reported pain, itch and quality of life were assessed by an electronic diary and questionnaire., Results: Twenty-four AGW and 12 vulvar HSIL patients were enrolled. All patients had a high treatment adherence (99%). No serious adverse events occurred and all adverse events (n = 27) were mild, transient and self-limiting. The treatment groups were not different in terms of safety and tolerability, lesion count and size, and patient-reported outcomes pain, itch and quality of life. Human papillomavirus load significantly reduced after 12 weeks of treatment with omiganan compared to placebo (-96.6%; 95% confidence interval -99.9 to -7.4%; P = .045) in AGW patients only., Conclusion: Topical omiganan appears to be safe in patients with AGW and vulvar HSIL and reduced human papillomavirus load after 12 weeks of treatment in AGW patients., (© 2019 The British Pharmacological Society.)

We aimed to characterise the population pharmacokinetics of cholesteryl ester transferase protein inhibitor DRL-17822 in healthy males and explore the effect of food and formulation on the oral absorption of DRL-17822 in 4 phase I studies. DRL-17822 was dosed orally (2-1000 mg) in 2 different drug formulations (nanocrystal formulation and amorphous solid dispersion formulation) after either an overnight fast, or a low-fat, continental or high-fat breakfast. A 2-compartment model with 6 transit absorption compartments best characterised the data. Additionally, a strong interaction of food and formulation on bioavailability was observed and parsimoniously characterised in the model by binning combinations of food state and formulation with similar bio-availabilities. The final model adequately characterised the pharmacokinetic data of DRL-17822 in healthy males including the complex interaction of food and drug formulation. The amorphous solid dispersion formulation has a lower food effect on bioavailability compared with the nanocrystal formulation., (© 2020 The Authors. British Journal of Clinical Pharmacology published by John Wiley & Sons Ltd on behalf of British Pharmacological Society.)

Aims: Growth hormone (GH) secretion is pulsatile and secretion varies highly between individuals. To understand and ultimately predict GH secretion, it is important to first delineate and quantify the interaction and variability in the biological processes underlying stimulated GH secretion. This study reports on the development of a population nonlinear mixed effects model for GH stimulation, incorporating individual GH kinetics and the stimulation of GH by GH-releasing hormone (GHRH)., Methods: Literature data on the systemic circulation, the median eminence, and the anterior pituitary were included as system parameters in the model. Population parameters were estimated on data from 8 healthy normal weight and 16 obese women who received a 33 μg recombinant human GH dose. The next day, a bolus injection of 100 μg GHRH was given to stimulate GH secretion., Results: The GH kinetics were best described with the addition of 2 distribution compartments with a bodyweight dependent clearance (increasing linearly from 24.7 L/h for a 60-kg subject to 32.1 L/h for a 100-kg subject). The model described the data adequately with high parameter precision and significant interindividual variability on the GH clearance and distribution volume. Additionally, high variability in the amount of secreted GH, driven by GHRH receptor activation, was identified (coefficient of variation = 90%)., Conclusion: The stimulation of GH by GHRH was quantified and significant interindividual variability was identified on multiple parameters. This model sets the stage for further development of by inclusion of additional physiological components to quantify GH secretion in humans., (© 2020 The Authors. British Journal of Clinical Pharmacology published by John Wiley & Sons Ltd on behalf of British Pharmacological Society.)

Background: Assessment of treatment effects in clinical trials requires valid information on treatment adherence, adverse events and symptoms. Paper-based diaries are often inconvenient and have limited reliability, particularly for outpatient trials., Objectives: To investigate the utility of an electronic diary (e-diary) application for patients with skin diseases in outpatient clinical trials., Methods: An e-diary application was developed and technically validated. Treatment adherence was defined as topical administration by the patient, and patient-reported outcomes, i.e. pain and itch, were evaluated by the e-diary in six clinical trials on newly tested topical drugs. Additionally, the proportion of patients capturing the applied topical drug by camera and filling in the pain and itch scores was defined as e-diary adherence, and patients' perception of usefulness and acceptability of the e-diary were evaluated., Results: Treatment adherence rates of the included 256 patients were high (median 98%, range 97-99%). E-diary adherence was also high with a median of 93% (range 87-97%) for capturing the applied drug by camera, and 89% (range 87-96%) and 94% (range 87-96%) for entering respectively the itch and pain score. Daily symptom scores provided good insights into the disease burden, and patients rated the e-diary as good to excellent with respect to user acceptability., Conclusions: The results suggest that the e-diary is an excellent way to ensure proper treatment administration, indicated by both the high user acceptability scores and high treatment adherence. Moreover, the e-diary may also be valuable for frequent and reliable monitoring of patient-reported outcomes in daily clinical practice., (© 2019 The Authors. Journal of the European Academy of Dermatology and Venereology published by John Wiley & Sons Ltd on behalf of European Academy of Dermatology and Venereology.)

Background: The quantification of human papilloma virus (HPV)-induced skin lesions is essential for the clinical assessment of the course of disease and the response to treatment. However, clinical assessments that measure dimensions of lesions using a caliper do not provide complete insight into three-dimensional (3D) lesions, and its inter-rater variability is often poor., Objective: The aim of this study was to validate a stereophotogrammetric 3D camera system for the quantification of HPV-induced lesions., Methods: The camera system was validated for accuracy, precision and interoperator and inter-rater variability. Subsequently, 3D photographs were quantified and compared to caliper measurements for clinical validation by Bland-Altman modelling, based on data from 80 patients with cutaneous warts (CW), 24 with anogenital warts (AGW) patients and 12 with high-grade squamous intraepithelial lesions of the vulva (vulvar HSIL) with a total lesion count of 220 CW, 74 AGW and 31 vulvar HSIL., Results: Technical validation showed excellent accuracy [coefficients of variation (CV) ≤ 0.68%] and reproducibility (CVs ≤ 2%), a good to excellent agreement between operators (CVs ≤ 8.7%) and a good to excellent agreement between different raters for all three lesion types (ICCs ≥ 0.86). When comparing 3D with caliper measurements, excellent biases were found for diameter of AGW (long diameter 5%), good biases were found for diameter of AGW (short diameter 10%) and height of CW (8%), and acceptable biases were found for the diameter of CW (11%) and vulvar HSIL (short diameter 14%, long diameter 16%). An unfavourable difference between these methods (bias 25%) was found for the assessment of height of AGWs., Conclusion: Stereophotogrammetric 3D imaging is an accurate and reliable method for the clinical visualization and quantification of HPV-induced skin lesions., (© 2019 The Authors. Journal of the European Academy of Dermatology and Venereology published by John Wiley & Sons Ltd on behalf of European Academy of Dermatology and Venereology.)

Drug safety is an important issue, especially in the experimental phases of development. Adverse immunostimulation (AI) is sometimes encountered following treatment with biopharmaceuticals, which can be life-threatening if it results in a severe systemic inflammatory reaction. Biopharmaceuticals that unexpectedly induce an inflammatory response still enter the clinic, even while meeting all regulatory requirements. Impurities (of microbial origin) in biopharmaceuticals are an often-overlooked cause of AI. This demonstrates that the current guidelines for quality control and safety pharmacology testing are not flawless. Here, based on two case examples, several shortcomings of the guidelines are discussed. The most important of these are the lack of sensitivity for impurities, lack of testing for pyrogens other than endotoxin, and the use of insensitive animal species and biomarkers in preclinical investigations. Moreover, testing for the immunotoxicity of biopharmaceuticals is explicitly not recommended by the international guidelines. Publication of cases of AI is pivotal, both to increase awareness and to facilitate scientific discussions on how to prevent AI in the future., (© 2019 The Authors. British Journal of Clinical Pharmacology published by John Wiley & Sons Ltd on behalf of British Pharmacological Society.)

Aims: To evaluate the availability of pharmacokinetic, safety and efficacy analyses specifically targeted at elderly, prior to the authorization of drugs., Methods: A cross-sectional, structured review of publicly available initial approval documents of Food and Drug Administration-approved drugs was performed. The 10 most frequently on-label prescribed drug classes, drugs with known pharmacokinetic differences in the elderly or drugs that are relatively contraindicated in elderly (e.g. anticholinergics or benzodiazepines) were included in the analyses., Results: In total, 1129 unique active pharmaceutical ingredients were found eligible for the analyses, of these, 506 were found in the Food and Drug Administration database (45%). The initial approval documents were available for 182 drugs. For the majority of the drugs, the initial approval documents in the database showed information on pharmacokinetics in elderly (n = 113; 62%). Furthermore, over time, the availability of information with regard to elderly increased statistically significantly from 0% in the period 1970-1979 to 76% for the period 2010-2018. Information on safety and efficacy was less frequently present, i.e. 42% and 45%, respectively and, moreover, the availability of information did not improve over time., Conclusion: The under-representation of elderly in clinical trials thereby challenging the external validity of benefit/risk assessments of launched drugs was confirmed. Priority should be given to a study population that is representative for the target population., (© 2019 The Authors. British Journal of Clinical Pharmacology published by John Wiley & Sons Ltd on behalf of British Pharmacological Society.)

Aims: Several studies have reported the under-representation of women in clinical trials, thereby challenging the external validity of the benefit/risk assessments of launched drugs. Our aim was to determine the extent to which women have been included in clinical trials used for drug registration and to analyse the fraction of women participating in phases I, II and III., Methods: We conducted cross-sectional, structured research into publicly available registration dossiers of Food and Drug Administration (FDA)-approved drugs that are prescribed frequently. Furthermore, we analysed compounds with high hepatic clearance and a known gender-related difference in drug response. In a sensitivity analysis, we compared figures with US disease prevalence data., Results: For 38 of the initial 137 drugs (28%), sufficient data were reported and publicly available. For these drugs, 185 479 trial participants were included, of whom 47% were female and 44% were male; gender was not reported for 9% of participants. However, the number of female participants varied with the phase of the trial, with 22% females in phase I trials vs. 48% and 49%, respectively, in phase II and III trials. When compared with US disease prevalence data, 10 drugs (26%) had a greater than 20% difference between the proportion of females affected with the disease compared with representation in clinical trials., Conclusions: From these publicly available data, there was no evidence of any systematic under-representation of women in clinical trials., (© 2018 The Authors. British Journal of Clinical Pharmacology published by John Wiley & Sons Ltd on behalf of British Pharmacological Society.)

Background: DNA viruses such as HPV rely on K + influx for replication. Both digoxin and furosemide inhibit the K + influx by interacting with cell membrane ion co-transporters (Na + /K + -ATPase and Na + -K + -2Cl - co-transporter-1, respectively). We therefore hypothesized that these two compounds in a topical formulation may be valuable in the treatment of HPV-induced warts. This new approach is called Ionic Contra-Viral Therapy (ICVT)., Objective: To evaluate systemic exposure, safety and tolerability of ICVT with a combination of furosemide and digoxin after repeated topical application in subjects with common warts. Furthermore, we aimed to evaluate pharmacodynamics effects of ICVT., Methods: Twelve healthy subjects with at least four common warts on their hands were included in the study and treated with a fixed dose of 980 mg topical gel containing 0.125% (w/w) digoxin and 0.125% (w/w) furosemide for 7 consecutive days on their lower back to assess safety and systemic exposure. Two warts were treated with 10 mg each and two served as negative controls to obtain preliminary evidence of treatment effect., Results: ICVT was well tolerated topically, and there was no evidence of systemic exposure of digoxin or furosemide. There were no clinical relevant safety findings and no serious adverse events (SAEs). A rapid and statistically significant reduction in diameter, height and volume of the warts was already observed at day 14., Conclusion: ICVT was found to be safe for administration to humans and 7 days of active treatment showed a statistical significant wart reduction compared to untreated control lesions, clearly indicating pharmacological activity., (© 2017 The Authors. Journal of the European Academy of Dermatology and Venereology published by John Wiley & Sons Ltd on behalf of European Academy of Dermatology and Venereology.)

Oligonucleotides (ONs) are short fragments of nucleic acids, currently being investigated as therapeutic agents. When administered subcutaneously (sc), ONs cause a specific local reaction originating around the injection site, such as erythema, itching, discomfort and pain, including more severe manifestations such as ulceration or necrosis. These injection site reactions (ISRs) are common, but rather poorly described in the literature. With this review, we aim to provide an overview on the extent of the problem of ISRs, based on reported incidence. A structured literature search was performed to identify reported incidence and clinical features of ISRs which yielded 70 manuscripts that contained information regarding ISRs. The data from literature was combined with data on file available at our institution. All sc administered ONs described in the literature lead to the occurrence of ISRs. The percentage of trial subjects that developed ISRs ranged from 22 to 100% depending on ON. The majority of ONs caused ISRs in more than 70% of the trial subjects. The severity of the observed reactions varied between different ONs. Occurrence rate as well as severity of ISRs increases with higher doses. For chemistry and target of the compounds, no clear association regarding ISR incidence or severity was identified. All ONs developed to date are associated with ISRs. Overcoming the problem of ISRs might add greatly to the potential success of sc-administered ONs. Knowledge of these skin reactions and their specific immunostimulatory properties should be increased in order to obtain ONs that are more suitable for long-term use and clinically applicable in a broader patient population., (© 2016 The British Pharmacological Society.)

Aim: The objective of this study was to investigate whether the pharmacokinetics of orally administered levofloxacin show 24 h variation. Levofloxacin was used as a model compound for solubility and permeability independent absorption and passive renal elimination., Methods: In this single centre, crossover, open label study, 12 healthy subjects received an oral dose of 1000 mg levofloxacin at six different time points equally divided over the 24 h period. Population pharmacokinetic modelling was used to identify potential 24 h variation in the pharmacokinetic parameters of this drug., Results: The pharmacokinetics of levofloxacin could be described by a one compartment model with first order clearance and a transit compartment to describe drug absorption. The fit of the model was significantly improved when the absorption rate constant was described as a cosine function with a fixed period of 24 h, a relative amplitude of 47% and a peak around 08.00 h in the morning. Despite this variation in absorption rate constant, simulations of a once daily dosing regimen showed that tmax , Cmax and the area under the curve at steady-state were not affected by the time of drug administration., Conclusion: The finding that the absorption rate constant showed considerable 24 h variation may be relevant for drugs with similar physicochemical properties as levofloxacin that have a narrower therapeutic index. Levofloxacin, however, can be dosed without taking into account the time of day, at least in terms of its pharmacokinetics., (© 2015 The British Pharmacological Society.)

Aims: LDL-receptor expression is inhibited by the protease proprotein convertase subtilisin/kexin type 9 (PCSK9), which is considered a pharmacological target to reduce LDL-C concentrations in hypercholesterolaemic patients. We performed a first-in-human trial with SPC5001, a locked nucleic acid antisense inhibitor of PCSK9., Methods: In this randomized, placebo-controlled trial, 24 healthy volunteers received three weekly subcutaneous administrations of SPC5001 (0.5, 1.5 or 5 mg kg(-1)) or placebo (SPC5001 : placebo ratio 6 : 2). End points were safety/tolerability, pharmacokinetics and efficacy of SPC5001., Results: SPC5001 plasma exposure (AUC(0,24 h)) increased more than dose-proportionally. At 5 mg kg(-1), SPC5001 decreased target protein PCSK9 (day 15 to day 35: -49% vs. placebo, P < 0.0001), resulting in a reduction in LDL-C concentrations (maximal estimated difference at day 28 compared with placebo -0.72 mmol l(-1), 95% confidence interval - 1.24, -0.16 mmol l(-1); P < 0.01). SPC5001 treatment (5 mg kg(-1)) also decreased ApoB (P = 0.04) and increased ApoA1 (P = 0.05). SPC5001 administration dose-dependently induced mild to moderate injection site reactions in 44% of the subjects, and transient increases in serum creatinine of ≥20 μmol l(-1) (15%) over baseline with signs of renal tubular toxicity in four out of six subjects at the highest dose level. One subject developed biopsy-proven acute tubular necrosis., Conclusions: SPC5001 treatment dose-dependently inhibited PCSK9 and decreased LDL-C concentrations, demonstrating human proof-of-pharmacology. However, SPC5001 caused mild to moderate injection site reactions and renal tubular toxicity, and clinical development of SPC5001 was terminated. Our findings underline the need for better understanding of the molecular mechanisms behind the side effects of compounds such as SPC5001, and for sensitive and relevant renal toxicity monitoring in future oligonucleotide studies., (© 2015 The British Pharmacological Society.)

Aim: Anthracycline-induced cardiotoxicity is (partly) mediated by free radical overload. A randomized study was performed in breast cancer patients to investigate whether free radical scavenger super oxide dismutase (SOD) protects against anthracycline-induced cardiotoxicity as measured by changes in echo, electrocardiography and an array of biomarkers., Method and Results: Eighty female, chemotherapy-naïve breast cancer patients (median age 49, range 24-67 years) scheduled for four or five courses of adjuvant 3 weekly doxorubicin plus cyclophosphamide (AC) chemotherapy, were randomly assigned to receive 80 mg PC-SOD (human recombinant SOD bound to lecithin) or placebo, administered intravenously (i.v.) immediately prior to each AC course. The primary end point was protection against cardiac damage evaluated using echocardiography, QT assessments and a set of biochemical markers for myocardial function, oxidative stress and inflammation. Assessments were performed before and during each course of chemotherapy, and at 1, 4 and 9 months after completion of the chemotherapy regimen. In all patients cardiac effects such as increases in NT-proBNP concentration and prolongation of the QTc interval were noticed. There were no differences between the PC-SOD and placebo-treated patients in systolic or diastolic cardiac function or for any other of the biomarkers used to assess the cardiac effects of anthracyclines., Conclusion: PC-SOD at a dose of 80 mg i.v. is not cardioprotective in patients with breast carcinoma treated with anthracyclines., (© 2014 The British Pharmacological Society.)

Early detection of drug-induced kidney injury is vital in drug development. Generally accepted biomarkers such as creatinine and blood urea nitrogen (BUN) lack sensitivity and early injury responses are missed. Many new biomarkers to detect nephrotoxicity for pre-clinical utilization have been described and their use is adopted in regulatory guidelines. However, guidance on appropriate biomarkers for clinical trials is minimal. We provide an overview of potentially useful kidney biomarkers that can be used in clinical trials. This includes guidance to select biomarkers suitable to capture specific characteristics of the (expected) kidney injury. We conclude that measurement of urinary kidney injury marker-1 (KIM-1) serves many purposes and is often an appropriate choice. Cystatin C captures effects on glomerular filtration rate (GFR), but this marker should preferably be combined with more specific markers to localize the origin of the observed effect. Untoward effects on tubules can be captured relatively well with several markers. Direct detection of glomerular injury is currently impossible since specific biomarkers are lacking. Indirect assessment of toxic effects on glomeruli is possible by using carefully selected panels of other injury markers. We conclude that it is possible to obtain appropriate information on nephrotoxicity in clinical drug development by using carefully selected panels of injury markers and suggest that identification and validation of specific glomerular biomarkers could be of great value., (© 2013 The British Pharmacological Society.)

Imagine a medicine that is expected to have very limited effects based upon knowledge of its pharmacology and (patho)physiology and that is studied in the wrong population, with low-quality studies that use a surrogate end-point that relates to the clinical end-point in a partial manner at most. Such a medicine would surely not be recommended. The use of recombinant human erythropoietin (rHuEPO) to enhance performance in cycling is very common. A qualitative systematic review of the available literature was performed to examine the evidence for the ergogenic properties of this drug, which is normally used to treat anaemia in chronic renal failure patients. The results of this literature search show that there is no scientific basis from which to conclude that rHuEPO has performance-enhancing properties in elite cyclists. The reported studies have many shortcomings regarding translation of the results to professional cycling endurance performance. Additionally, the possibly harmful side-effects have not been adequately researched for this population but appear to be worrying, at least. The use of rHuEPO in cycling is rife but scientifically unsupported by evidence, and its use in sports is medical malpractice. What its use would have been, if the involved team physicians had been trained in clinical pharmacology and had investigated this properly, remains a matter of speculation. A single well-controlled trial in athletes in real-life circumstances would give a better indication of the real advantages and risk factors of rHuEPO use, but it would be an oversimplification to suggest that this would eradicate its use., (© 2012 The Authors. British Journal of Clinical Pharmacology © 2012 The British Pharmacological Society.)

Biochemical characterization of the haemostatic system has advanced significantly in the past decades. Sub-systems, such as coagulation, fibrinolysis, blood cells and platelets and the vessel wall have been studied by specialists, mostly separately and independently. The time has come to integrate the approaches, and, in particular, to develop tests to document the state of the whole system and to have available adequate pharmacodynamic tests to evaluate treatments. Many examples are available to show that traditional general methods of clotting and lysis do not provide the information that is desired. The present tendency is to use specific methods for specific factors or effects which are very limited in pharmacological information. There is also increasing awareness of the occurrence of rather broad interindividual variability in the haemostatic system. This suggests that individually tailored treatments are required. This is the more relevant since haemostasis is a balance and treatment should be positioned between efficacy and safety. The conclusion is reached that there is a need for integrated or global methods or sets of methods that reflect the complexity and individual status appropriately and allow the practitioner to judge the effects of interventions and their individual aspects., (© 2011 The Authors. British Journal of Clinical Pharmacology © 2011 The British Pharmacological Society.)

Aims: To develop a limited sampling strategy to determine ciclosporin systemic exposure [area-under-the-curve(AUC)]. This is meant to be the first step in a future study of the relationship between AUC and the biological effects of ciclosporin., Methods: The pharmacokinetics of ciclosporin was investigated prospectively following stem cell transplantation (SCT) in 17 children, aged 1.8-16.1 years. Ciclosporin was given twice daily, intravenously over a short infusion of 2 h duration during the early post-SCT period, or orally later on, when oral medication was well tolerated. Parameter estimation was performed using nonlinear mixed effect modelling as implemented in the NONMEM program. Individual empirical Bayes estimates of clearance and distribution volume were correlated with the demographic variables., Results: Pharmacokinetics was described adequately with a two-compartment model with lag time (population estimates: CL = 11.3 l h(-1); V(c) = 16.5 l; V(p) = 59.9 l; t(1/2) absorption = 0.78 h, t(lag) = 0.6 h). The AUCs, determined for the combination of trough level with one time point between 2 and 3 h after dosing, correlated very well with the reference AUC (r(2) = 0.97). No correlation was found between clearance and distribution volume, and the demographic patient variables length, body weight, age and glomerular filtration rate., Conclusion: A two-point limited sampling strategy, in combination with a Bayesian fitting procedure using the pharmacokinetic population model described, can adequately determine the AUC of ciclosporin. Since no correlation between clearance and body weight was found, dosing ciclosporin per kg bodyweight is not supported by the results of this study. We suggest starting with a fixed dose, followed by AUC determination and dose adjustment.

Aim: To study the pharmacokinetics (PK), safety and tolerability of single rising doses up to 80 mg of superoxide dismutase covalently linked to lecithin (PC-SOD) in healthy White volunteers., Methods: This double-blind, placebo-controlled, four-period cross-over study was performed in eight healthy volunteers (four male/four female). Three doses of PC-SOD (20, 40 and 80 mg) and placebo were administered intravenously in randomized order. Serum and urinary PC-SOD concentrations were measured predose and up to 96 h after dosing. In addition to standard safety measurements, the urinary excretion of N-acetyl-beta-glucosaminidase, alpha-glutathione S-transferase (alpha-GST) and pi-GST was measured to evaluate renal function. The PK of PC-SOD was analysed using noncompartmental and compartmental methods., Results: All treatments were well tolerated, and no obvious relationship between adverse events and treatment was observed. No effects of PC-SOD on renal function could be detected. Dose normalized C(max) and AUC were not different between the different dosages, indicating linearity of plasma concentrations with dose. Estimated PC-SOD clearance was 2.54 ml min(-1)[95% confidence interval (CI) 2.07, 2.83]. The terminal half-life was estimated to be 1.54 days (95% CI 0.93, 2.15). SOD activity was elevated above baseline for 19 +/- 6 h after the 80-mg dose., Conclusions: Single intravenous administrations of PC-SOD in doses up to 80 mg were well tolerated in healthy White male and female volunteers. With the doses used, SOD activity was linearly related to the dose; after the 80-mg dose it was present for an appreciable period. These findings suggest that it is worthwhile to investigate PC-SOD in clinical conditions characterized by a high radical overload.

Aim: To evaluate a high-dose continuous furosemide regimen in infants after cardiac surgery., Methods: Fifteen haemodynamically unstable infants with volume overload admitted to a paediatric intensive care unit were treated with an aggressive furosemide regimen consisting of a loading bolus (1-2 mg kg(-1)) followed by a continuous infusion at 0.2 mg kg(-1) h(-1) which was adjusted according to a target urine output of 4 ml kg(-1) h(-1). Frequent sampling for furosemide concentrations in blood and urine was done for 3 days with simultaneous assessment of sodium excretion and urine output., Results: The mean furosemide dose was 0.22 (+/- 0.06), 0.25 (+/- 0.10) and 0.22 (+/- 0.11) mg kg(-1) h(-1) on the first, second and third day, respectively. Median urine production was 3.0 (0.6-5.3), 4.2 (1.7-6.6) and 3.9 (2.0-8.5) ml kg(-1) h(-1), respectively, on the first, second and third day of the study. The target urine production was reached at a median time of 24 (6-60) h and this was maintained during the study period. The regimen did not result in toxic serum concentrations and was haemodynamically well tolerated., Conclusion: High-dose continuous furosemide infusion for 72 h in haemodynamically unstable infants after cardiac surgery appears to be a safe and effective treatment for volume overload. Development of tolerance against the effects of furosemide and ototoxic furosemide concentrations were not observed.

What Is Already Known About This Subject: * Many studies have investigated the effects of thiazolidinediones on isolated biochemical markers (biomarkers) or sets of markers in Type 2 diabetes mellitus (T2DM) patients and healthy volunteers. * However, a limited number of parameters is not capable of capturing the broad response to pharmacological intervention with these types of (pleiotropic) drugs, which are known to activate the nuclear transcription factor peroxisome proliferator activated receptor gamma (PPARgamma). * Our study tested the new hypothesis (primary objective) that nuclear magnetic resonance (NMR)-based metabolomics, capable of providing a readout of global metabolite concentrations in biofluids, could provide a better (more holistic) picture of the the multiparametric response to pharmacological intervention with a PPARgamma agonist and thus yield a broad array of biomarkers ('fingerprint') that could be used to support and expedite clinical development of novel thiazolidinediones., What This Study Adds: * NMR-based metabolomics coupled with sophisticated bioinformatics is indeed capable of identifying rapid changes in global metabolite profiles in urine and plasma (treatment 'fingerprints'), which may be linked to the well-documented early changes in hepatic insulin senstitivity following thiazolidinedione intervention in T2DM patients. * Consequently, this approach (upon proper validation) comprises an important new addition to the early clinical development 'proof of concept' toolbox for thiazolidinediones, and may also be applicable to other classes of drugs., Aims: To explore the usefulness of metabolomics as a method to obtain a broad array of biomarkers for the pharmacological effects of rosiglitazone (RSG) in plasma and urine samples from patients with type 2 diabetes mellitus (T2DM) and healthy volunteers (HVs). Additionally, we explored the differences in metabolite concentrations between T2DM patients and HVs to identify a putative metabolic disease fingerprint for T2DM., Methods: (1)H nuclear magnetic resonance (NMR) spectroscopy was used to profile blood plasma and urine samples of 16 T2DM patients and 16 HVs receiving RSG 4 mg or placebo twice daily for 6 weeks. Multivariate analyses were employed to identify treatment- and disease-related effects on global endogenous metabolite profiles., Results: RSG treatment led to a rapid relative reduction in urinary hippurate and aromatic amino acids as well as an increase in plasma branched chain amino acids and alanine, glutamine and glutamate in the T2DM group. No RSG treatment effects were noted in the HV group. Exploratory baseline analyses showed that urine and plasma metabolites discriminated between genders and disease state. T2DM patients showed a relative increase in urinary concentrations of several amino acids, citrate, phospho(enol)pyruvate and hippurate. Putative T2DM-related changes in plasma were largely attributable to increased plasma lipids., Conclusion: The results of this study indicate that NMR-based metabolomics of urine and blood plasma samples can yield a broad array of early responding biomarkers for the effects of RSG in T2DM patients, as well as nonglucose biomarkers that may reflect the T2DM state.

Aims: Pre-clinical data suggest that the racemic phyto-oestrogen 8-prenylnaringenin (8-PN) may have beneficial effects in postmenopausal women and may become an alternative to classical hormone replacement therapy (HRT) treatment regimes. The aim of this study was to investigate the pharmacokinetics, endocrine effects and tolerability of chemically synthesized 8-PN in postmenopausal women., Methods: The study was performed using a randomized, double-blind, placebo-controlled, dose-escalation design with three groups of eight healthy postmenopausal women. In each group six subjects received 8-PN and two subjects placebo. 8-PN was given orally in doses of 50, 250 or 750 mg. Drug concentrations in serum, urine and faeces were measured up to 48 h and follicle-stimulating hormone/luteinizing hormone (LH) concentrations up to 24 h., Results: All treatments were well tolerated and associated with a low incidence of (drug unrelated) adverse events. Serum concentrations of free 8-PN showed rapid drug absorption and secondary peaks suggestive of marked enterohepatic recirculation. Independent of the treatment group, approximately 30% of the dose was recovered in excreta as free compound or conjugates over the 48-h observation period. The first C(max) and AUC(0-48 h) showed dose linearity with ratios of 1 : 4.5 : 13.6 (C(max)) and 1 : 5.2 : 17.1 (AUC). The750- mg dose decreased LH concentrations by 16.7% (95% confidence interval 0.5, 30.2)., Conclusion: Single oral doses of up to 750 mg 8-PN were well tolerated by postmenopausal women. The pharmacokinetic profile of 8-PN was characterized by rapid and probably complete enteral absorption, high metabolic stability, pronounced enterohepatic recirculation and tight dose linearity. The decrease in LH serum concentrations found after the highest dose demonstrates the ability of 8-PN to exert systemic endocrine effects in postmenopausal women.

Aims: To characterize the pharmacokinetics of fumarates in healthy subjects., Methods: Ten subjects received a single fumarate tablet (containing 120 mg of dimethylfumarate and 95 mg of calcium-monoethylfumarate) in the fasted state and after a standardized breakfast in randomized order. Prior to and at fixed intervals after the dose, blood samples were drawn and the concentrations of monomethylfumarate, the biologically active metabolite, as well as dimethylfumarate and fumaric acid were measured using high-performance liquid chromatography., Results: After a lag time, a transient increase in serum monomethylfumarate concentrations in the blood was observed, whereas dimethylfumarate and fumaric acid concentrations remained below the detection limit. The tlag was 240 min [range 60-603 min; 95% confidence interval (CI) 139, 471] shorter when the tablet was taken after an overnight fast (90 min; range 60-120 min; 95% CI 66, 107) than when taken with breakfast (300 min; range 180-723 min; 95% CI 0, 1002). The tmax was 241 min (range 60-1189 min, 95% CI 53, 781) shorter when the tablet was taken after an overnight fast (182 min; range 120-240 min; 95% CI 146, 211) than when taken with breakfast (361 min; range 240-1429 min; 95% CI 0, 1062). The mean Cmax for monomethylfumarate in the blood of fasting subjects was to 0.84 mg l(-1) (range 0.37-1.29 mg l(-1); 95% CI 0.52, 1.07) and did not differ from that in fed subjects (0.48 mg l(-1); range 0-1.22 mg l(-1); 95% CI 0, 5.55)., Conclusions: The pharmacokinetics of monomethylfumarate in healthy subjects after a single tablet of fumarate are highly variable, particularly after food intake. Further experiments exploring the pharmacokinetics of oral fumarates are warranted in order to elucidate the mechanisms underlying variability in response in patients., (Copyright 2004 Blackwell Publishing Ltd)

Aim: To investigate a motilin effect on gallbladder volume in healthy volunteers and patients with functional dyspepsia., Methods: Forty-three healthy volunteers and 10 patients with functional dyspepsia received motilin (4 pmol.min/kg) or placebo in four separate double-blind, randomized, placebo-controlled, cross-over studies. The gallbladder volume was measured by ultrasonography. Analysis of variance of the combined data of these studies was performed to investigate a motilin effect on gallbladder volume and potential differences between patients and healthy volunteers., Results: The baseline gallbladder volume was similar for placebo and motilin treatment, as well as for patients and healthy volunteers. Motilin, compared with placebo, significantly decreased the gallbladder volume in healthy volunteers (P = 0.003) and patients (P < 0.0001). A linear concentration-response relationship was observed. The decrease in gallbladder volume by motilin was greater in patients (P = 0.03). The motilin effect was consistent between studies., Conclusion: The interdigestive gallbladder volume is a non-invasive end-point for motilin activity, displaying a consistent response across studies, a clear response to motilin and a clear concentration-response relationship. However, it is less suitable as a biomarker for future pharmacological studies on motilin agonists or antagonists as the effect is probably indirect, and a relatively large study population of 27 subjects is required to demonstrate a 15% decrease in gallbladder volume. Further investigation is required to confirm altered gallbladder motility as a feature of functional dyspepsia.

Aim: To assess the effects of the motilin receptor antagonist RWJ-68023 on basal and motilin-stimulated proximal gastric volume., Methods: Eighteen healthy male volunteers received RWJ-68023 in two different doses or placebo for 135 min. After 45 min, subjects received a motilin infusion for 90 min. Proximal gastric volume was measured with a barostat at constant pressure and during isobaric distensions. Abdominal symptoms were scored using visual analogue scales. Motilin and RWJ-68023 concentrations were assessed by radioimmunoassay and liquid chromatography-mass spectrometry, respectively., Results: Both dosages of RWJ-68023 were safe and well tolerated. The most common adverse events were of gastrointestinal origin. RWJ-68023 did not affect basal proximal gastric volume, but the high-dose RWJ-68023 reduced the contractile effect of motilin on the stomach. This antagonizing effect of RWJ-68023 was only significant (P = 0.014) during the distension procedure., Conclusions: The RWJ-68023 doses used in this study were selected to accomplish plasma concentrations that would block the motilin effect entirely. However, the antagonizing effect of RWJ-68023 was partial and only present when the tonic condition of the stomach was modulated by motilin.

Aims: The role of motilin in the regulation of upper gastrointestinal (GI) motility is well defined. However, little is known about the effects on the distal GI tract. To investigate the effect of exogenous motilin on rectal function, barostat measurements in the rectum were performed and lower abdominal symptoms were scored., Methods: Eight fasted, healthy volunteers were infused intravenously with synthetic motilin or placebo over 90 min in a double-blind, randomized, cross-over design. Rectum volume was measured with a barostat device during constant pressure and during isobaric distensions. Lower abdominal symptoms were scored by visual analogue scales. Plasma motilin concentrations were measured by radioimmunoassay., Results: Baseline rectum volumes were similar between treatments: 185 +/- 62 mL (motilin) and 136 +/- 41 mL (placebo). During the constant pressure procedure, motilin increased rectum volume [area under the effect curve (AUEC)] by 6%[95% confidence interval (CI) -3, 16] of baseline, compared with placebo. During isobaric distensions motilin increased rectum volume (AUEC) by 43 mL (95% CI 0.4, 85; P < 0.05) and compliance by 10 mL mmHg-1 (95% CI 0.3, 20; P < 0.05) relative to placebo. Motilin did not induce changes in the sensation of rectal feelings., Conclusion: Exogenous motilin increased rectal compliance in healthy volunteers, without affecting rectal sensations.

Aims: Heparin releases tissue factor pathway inhibitor (TFPI) from the endothelium and this release may decrease after repeated high dose heparin administration. The primary aim was to investigate and quantify this phenomenon during a short low dose heparin infusion. Also, the effects of heparin on tissue plasminogen activator (t-PA) were studied., Methods: Nine healthy, nonsmoking, male volunteers (range 19-23 years) received a continuous heparin infusion (2000 IU) over 40 min. The endothelial TFPI release rate was estimated from the total TFPI concentration profile using a pharmacokinetic model., Results: Mean +/- s.d. total and free TFPI increased from 62.9 +/- 9.4/8.3 +/- 2.1 ng ml-1 at baseline to 237.2 +/- 40.9/111.0 +/- 19.9 ng ml-1 after 40 min infusion. The relationship between heparin concentration (anti-IIa activity) and TFPI concentration followed a maximum effect model and a clockwise loop (proteresis) was observed. The TFPI release rate rapidly increased to maximum of 200 +/- 45 micro g min-1 after 17.5 min heparin infusion but did not increase further although heparin concentrations further doubled. In contrast to TFPI, t-PA antigen decreased from 5.6 +/- 1.0 at baseline to 4.5 +/- 1.0 ng ml-1 at the end of infusion (t = 40 min) (difference of 1.1 ng ml-1 (95% confidence interval; 0.9, 1.3)., Conclusions: Our application of concentration-effect models and pharmacokinetic principles to these haemostatic variables showed that endothelial TFPI release has a maximum that is already reached at low heparin dose, corresponding with an anti-IIa activity of 0.08 IU ml-1. The relationship between anti-IIa activity and TFPI release rate showed signs of acute tolerance (clockwise loop) indicating exhaustion of endothelial TFPI pools. These findings may be of importance for the heparin dose used in conditions such as unstable angina, in which the favourable effects of heparin have been ascribed to its ability to release TFPI.

Aims: To investigate the pharmacokinetic and pharmacodynamic interaction of the antithrombotic pentasaccharide fondaparinux (Org31540/SR90107A), given subcutaneously, and oral warfarin in healthy subjects., Methods: This study was performed according to a randomised, three-way cross-over, placebo-controlled, double-blind design in 12 healthy male subjects. The treatment consisted of five subcutaneous (s.c.) injections of fondaparinux (4 mg) or placebo at 24 h intervals. Oral dosing of warfarin or placebo was added to the fourth (15 mg) and fifth (10 mg) s.c. injection. Blood samples for pentasaccharide assay, PT and APTT were drawn before the first s.c. dose of the pentasaccharide and over a 6 day period thereafter., Results: Fondaparinux administered to healthy male volunteers alone or in combination with oral warfarin was well tolerated and no serious adverse events were observed. No differences were found in the AUC (43 vs 44 mg l(-1) h), Cmax (645 vs 678 ng ml(-1)) or elimination half-life (13.8 vs 14.1 h) of fondaparinux between the pentasaccharide-only and the combination treatment. The effect of warfarin on PT (mean maximal increase: 8.2 s.) was not influenced by the presence of the pentasaccharide (mean maximal increase in PT: 9.1 s.). After all treatments a small rise in APTT was seen. No further differences could be detected in the pharmacodynamic parameters following the three treatments., Conclusions: The coadministration of warfarin did not influence the pharmacokinetics of fondaparinux in healthy subjects. PT can still be used to monitor the effect of oral anticoagulants during the switch from antithrombotic treatment with pentasaccharide to full oral anticoagulant therapy.

Aim: To assess non-invasively the dose-response relations for the effects of exogenous motilin on antrum contraction frequency, gall-bladder volume and gastric myoelectrical activity., Methods: In a double-blind, randomized, placebo-controlled, five-way crossover study, 10 fasted healthy volunteers were infused intravenously with synthetic human motilin (0.5, 1, 2 and 4 pmol x min/kg) or placebo for 60 min. Gall-bladder volume and antrum contractions were assessed by ultrasonography and gastric myoelectrical activity by electrogastrography. Motilin concentrations were measured using a radioimmunoassay., Results: Baseline plasma motilin levels (60 pmol/L) were similar for all treatments. Motilin levels increased upon the start of infusion and rapidly returned to baseline after cessation of the infusion. At motilin doses of 2 and 4 pmol.min/kg, the antrum contraction frequency was significantly augmented, with maximum differences of two contractions per 2-min interval compared to placebo, while no changes in gastric myoelectrical activity were observed. Changes in gall-bladder volume were not significantly different for any of the motilin doses compared to placebo., Conclusions: Motilin increased antrum contraction frequency, whereas no effect on gastric myoelectrical activity was observed. Antrum contraction frequency appears to be a useful biomarker for motilin efficacy, and motilin doses of 2 and 4 pmol x min/kg were equally effective.

Aims: To determine the influence of the hand circulation on the determination of venous distensibility with venous occlusion plethysmography., Methods: In a randomised study, duplicate measurements of forearm venous distensibility, with and without a wrist cuff, were made over occlusion periods of 3 and 12 min in eight volunteers. Treatments were compared with paired Student's t-tests and differences are presented as 95% confidence intervals (CI). Intra-subject variability was assessed with analysis of variance., Results: Non-significant differences in increases in forearm volume between the occlusions with and without wrist cuff were found for the 3 min occlusion (CI: -0.4, + 0.2%) and the 12 min occlusion period (CI: -0.7, + 0.2%). However, the coefficient of variation was lower with the use of a wrist cuff; after 3 min occlusion (12% vs 19%) and after 12 min of occlusion (14% vs 24%). Forearm volume after 12 min of venous occlusion was 0.5% (CI: + 0.4, + 0.7) higher than after 3 min., Conclusions: Although venous distensibility was equal when assessed with and without wrist cuff, exclusion of the hand circulation reduces intraindividual variability. Equilibrium in forearm volume is not reached after 3 min period of venous occlusion, as often assumed. The magnitude of the additional increase after prolonged occlusion stresses the need for well-controlled studies.

Aims: To study the delivery of 15 mg beclomethasone 17,21-dipropionate (BDP) to the distal part of the small bowel for three oral sustained-release formulations (I-III) and a reference capsule in volunteer ileostomists, and to compare these findings with the in vitro dissolution profiles., Methods: Two groups of nine ileostomy volunteers (aged 20-61 years), who were otherwise healthy, were enrolled in the study. The recovery of BDP and its metabolite beclomethasone 17-monopropionate (B17P) in ileostomy effluent was investigated in a cross-over study after administration of formulations I or II or a reference capsule containing micronised BDP, and in a second open study after administration of formulation III. Radio-opaque granules were coadministered for evaluation of gastrointestinal passage. Ileostomy effluents were collected hourly for 10-12 h following drug intake. After marker beads had been counted on X-rays, ileostomy collections were analysed for BDP and its metabolites. Cumulative recovery, lag-time and mean transit time were determined for drug and marker beads., Results: Gastrointestinal passage characteristics were similar for all treatments. Total drug recovery was approximately three times higher for the sustained-release formulations than for the reference capsule. Recovery of B17P from stoma fluid samples was significantly lower for formulation III than for formulations I and II., Conclusions: The novel oral formulations delivered substantial amounts of steroid drug at the distal small bowel/proximal colon, which may warrant further studies to evaluate clinical applicability.

Aims: Application of single methods to assess liver blood flow (LBF) yielded conflicting results on the magnitude and duration of effect on LBF of oral nifedipine and captopril. The aim of this study was to investigate the influence of these drugs on LBF by simultaneous use of ICG infusion and echo-Doppler., Methods: The study was performed according to a double-blind, placebo-controlled, randomized, cross-over design in nine healthy male volunteers. After an overnight fast and an equilibration period, subjects received a continuous i.v. indocyanine green (ICG) infusion for 4 h. At presumed ICG steady state (t=45 min), subjects were dosed with oral nifedipine (20 mg), captopril (50 mg) or placebo. During the experiment, blood sampling for ICG assay and measurement of portal venous blood flow (echo-Doppler) took place regularly. Treatments were compared using analysis of variance. Differences are reported with 95% confidence intervals (CI)., Results: The area under the curves (AUC) for ICG over 1 h and over 3 h after nifedipine were 15% (difference in AUC: + 0.6, + 7.0 mg l(-1) min) and 22% (+ 7.0, + 28.4 mg l(-1) min) lower compared with placebo. After captopril, the AUC values were 8-10% lower compared with placebo but the 95% CIs included zero. Portal venous flow was 15% (+ 5, + 86 ml min(-1)) higher compared to placebo after nifedipine but not after captopril (-3%; -49, +33 ml min(-1)). The duration of effect on liver blood flow lasted approximately 2 h but was variable (range: 40-160 min). The time to maximal blood flow increase and the duration of effect after nifedipine were very similar for both measures of LBF. Changes in ICG concentrations could be reasonably well predicted from the changes in portal blood flow., Conclusions: Nifedipine increases LBF for a substantial period of time but the effect is variable between subjects. This effect could be detected by both the ICG method and echo-Doppler and the findings of both methods were in agreement. In this respect it is likely that captopril does not influence LBF in healthy volunteers as no effect was detected with either method.

Aims: To provide methods for the translation of the concentration-time profile of highly cleared marker compounds into the underlying clearance and hepatic blood flow profile., Methods: Continuous infusion of indocyanine green or sorbitol was used to assess the effect of the hepatic blood flow modifiers exercise, somatostatin and octreotide. Three distinct methods are described for the translation of concentration into flow: 1. assuming successive phases of constant clearance 2. point to point estimation of clearance using estimates of concentration change 3. using a parametric description of the flow profile in combination with the differential equations describing the change in marker concentrations., Results: The marker compound concentration profiles are adequately described using the different methods. Exercise results in a decrease in hepatic blood flow of about 80%. Somatostatin and octreotide elicit an indistinguishable hepatic blood flow decrease from 1.49 to 1.07 l min(-1). Return to baseline takes much longer for octreotide (half-life 126+/-104 min) than for somatostatin (half-life 4.29+/-3.55 min)., Conclusions: Translation of concentration profiles into clearance profiles is possible making continuous assessment of hepatic blood flow feasible.

Echo-Doppler measurements of portal venous blood flow in intrahepatic branches and indocyanine green (ICG) clearance after continuous i.v. infusion as measure for liver blood flow were compared to evaluate the increase in splanchnic blood flow after food intake. It was shown that both methods assessed the changes in flow in a similar manner. Changes in blood flow in intrahepatic portal vein branches measured with echo-Doppler adequately predicted the change in ICG concentrations. Hence, echo-Doppler measurements of hepatic portal blood flow in intrahepatic branches can be used to estimate changes in total liver blood flow.

1. The pharmacokinetics of nisoldipine (10 mg) was assessed in 10 healthy subjects after single dose and multiple dose oral administration. Apparent liver blood flow was measured, using ICG before and during the absorption phase of nisoldipine. 2. Apparent liver blood flow was increased both on acute and short-term administration of nisoldipine, basal flow being lower on multiple dosing than on acute administration (P less than 0.02). 3. A positive relationship was found between the increase in apparent liver blood flow during absorption of nisoldipine and the flow-dependent part of the total AUC of nisoldipine. 4. The findings of this study indicate that a variable liver blood flow response during the absorption phase of nisoldipine contributes to the pharmacokinetic variability of the drug, both on acute and multiple dose administration.