Two placebo-controlled crossover studies in healthy subjects to evaluate gastric acid neutralization by an alginate-antacid formulation (Gaviscon Double Action).

OBJECTIVE: To investigate the intragastric acid neutralization activity of a combined alginate-antacid formulation. SIGNIFICANCE: Published studies have investigated the reflux-suppressing alginate component of Gaviscon Double Action (Gaviscon DA; RB, UK) but intragastric acid neutralization activity of the antacid component has not been evaluated in vivo. METHODS: Intragastric pH monitoring, using a custom-made 10-electrode catheter, was evaluated in a two-part exploratory study in healthy subjects; Part I (n = 6) tested suitability of the catheter using antacid tablets (Rennie; Bayer, Germany); Part II (n = 12) evaluated gastric acid neutralization activity of Gaviscon DA liquid (20 ml) versus placebo in fasted subjects using a randomized, open-label, crossover design. The primary endpoint was the percentage of time that intragastric pH ≥4 was measured during 30 min post-treatment. A confirmatory study of identical design was subsequently conducted (n = 20). RESULTS: Monitoring pH using the multielectrode catheter was a viable approach, directly detecting changes in intragastric pH following a single dose of antacid tablets. In the exploratory study, the percentage of time that pH ≥4 during 30 minutes post-treatment was 46.8% with Gaviscon DA liquid versus 4.7% with placebo (p = 0.0004). These findings were supported by the confirmatory study, where pH ≥4 was recorded 50.8% of the time with Gaviscon DA versus 3.5% with placebo (p = 0.0051). In this study, Gaviscon DA was safe and well tolerated. CONCLUSIONS: These studies demonstrate the effective acid neutralizing capacity of Gaviscon DA versus placebo in healthy, fasted subjects. This adds to the evidence base for the combination of alginates and antacids.

Serial CSF sampling over a period of 30 h via an indwelling spinal catheter in healthy volunteers: headache, back pain, tolerability and measured acetylcholine profile.

BACKGROUND/AIM: Timed interval cerebrospinal fluid (CSF) sampling by indwelling catheterization can be a valuable corroborative tool for the pharmacokinetic and pharmacodynamic assessment of drugs. CSF sampling in studies on drug candidates for Alzheimer's disease have been conducted in evaluations of the biomarkers acetylcholine (ACh), tau proteins, amyloid precursor protein and beta-amyloid fragments. The primary aim of this study was to study the feasibility and the burden on the healthy volunteers of serial CSF sampling within the contract research organization environment in order to establish a standardized research tool for future drug development studies. MATERIALS AND METHODS: This study is a validation study in healthy subjects: eight healthy male subjects aged 55-75 years were enrolled. After eligibility had been confirmed, the subjects were admitted to the clinical pharmacology unit 2 days before starting the CSF sampling procedure. Hydration by drip infusion of 2 L saline was performed for 24 h before starting the CSF sampling procedure, and for antithrombotic purposes, Fraxiparine (nadroparine calcium) was given 12 and 36 h after intradural catheterization. CSF catheterization was performed by board-certified anesthesiologists with experience in inserting indwelling intrathecal catheters. Subjects only required to remain in a horizontal position for the first 24 h after removal of the catheter. CSF and blood samples were collected by interval sampling over a 30-h period. RESULTS: The study was completed by seven of the eight subjects. Six subjects who completed the study reported adverse effects (AEs) which were all mild and from which they recovered during their stay in the clinic. A total of 25 AEs were reported of which 13 were considered to be procedure-related. The procedure was well tolerated by all participating subjects, and the VAS scale scores for headache and back pain were low. CSF samples were analyzed for ACh. All values were above the lowest limit of quantification. On average, the ACh concentration started at a low level but rose between 1 and 2 h after insertion of the catheter and then remained high during the whole sampling period up to 30 h. CONCLUSION: Serial sampling of CSF in seven healthy volunteers up to 30 h occurred without serious complications and was well tolerated. The CSF collected was of good quality and facilitated the assessment of an Alzheimer's disease-sensitive biomarker. We conclude that this validation study can form the basis for future patient studies aimed at elucidating disease mechanisms and the pharmacodynamics of drugs in the developmental stage.

Pharmacokinetics of fingolimod (FTY720) and a combined oral contraceptive coadministered in healthy women: drug-drug interaction study results.

BACKGROUND: Fingolimod has a novel mechanism of action in multiple sclerosis, being a first-in-class sphingosine 1-phosphate receptor modulator. Because of a potential risk of fetal toxicity based on animal studies, women of childbearing potential are advised to take effective contraceptive measures during and for 2 months after stopping fingolimod therapy. To assess whether the efficacy of a combined oral contraceptive (OC) could be compromised during fingolimod therapy, a steady-state, drug-drug interaction study of fingolimod with ethinylestradiol/levonorgestrel was performed in healthy female volunteers. OBJECTIVE: To assess the interaction between fingolimod 0.5 mg once daily and ethinylestradiol 30 µg/ levonorgestrel 150 µg once daily at a steady state. METHODS: 31 healthy women received the combined OC only on Days 1 - 14, followed by OC plus fingolimod on Days 15 - 28. RESULTS: In the presence of fingolimod, ethinylestradiol pharmacokinetics were unchanged, and levonorgestrel maximum plasma concentration at steady state and area under the concentration-time curve during a dosing interval increased by factors of 1.10 (90% CI 1.05 - 1.16) and 1.22 (90% CI 1.18 - 1.27), respectively. CONCLUSIONS: Fingolimod therapy does not alter the pharmacokinetics of the combined OC ethinylestradiol/ levonorgestrel to a clinically significant degree. Ethinylestradiol/levonorgestrel does not alter the pharmacokinetics of fingolimod. Women receiving fingolimod therapy are able to use a combined OC as a means of effective birth control.

Application of dried blood spot sampling combined with LC-MS/MS for genotyping and phenotyping of CYP450 enzymes in healthy volunteers.

An early clinical development study (phase I) was conducted to determine the usefulness of dried blood spot (DBS) sampling as an alternative to venous sampling for phenotyping and genotyping of CYP450 enzymes in healthy volunteers. Midazolam (MDZ) was used as a substrate for phenotyping CYP3A4 activity; the concentrations of MDZ and its main metabolite 1'-hydroxymidazolam (1-OH MDZ) were compared between the DBS method from finger punctures, plasma and whole blood (WB), drawn by venipuncture, whereby several methodological parameters were studied (i.e. punch width, amount of dots analyzed and storage time stability). Genotyping between DBS and venous WB samples was compared for CYP2D6 (*3, *4, *6), CYP2C19 (*2, *3), CYP3A4 (*1B) and CYP3A5 (*3C). In addition, the subject's and phlebotomist's satisfaction with venous blood sampling compared with the DBS method was evaluated using a standardized questionnaire. An LC-MS/MS method for the quantification of the MDZ and 1-OH MDZ concentrations in DBS samples was developed and validated in the range of 0.100-100 ng/mL. No compromises were made for the limits of quantification of the DBS-LC-MS/MS method vs the authentic plasma and WB methods.

Phase I study of Solulin, a novel recombinant soluble human thrombomodulin analogue.

Solulin is a novel recombinant soluble derivative of human thrombomodulin. In this first human study of Solulin, the safety, tolerability, pharmacokinetics and pharmacodynamics of Solulin in 30 healthy volunteers in response to single (0.6-30 mg) and 12 healthy volunteers in response to multiple (1 and 10 mg) ascending intravenous bolus doses compared to placebo are described. Solulin was shown to be well tolerated, and demonstrated linear pharmacokinetics over the clinically relevant dose range, with a plasma elimination half-life of 15-30 hours, indicating that a less than daily dose may be required for therapeutic use. Steady-state plasma levels after multiple dosing were reached after 48 hours. Solulin has shown to be able to inhibit thrombin generation without increasing levels of aPC/PCI complexes. Coagulation parameters INR and PT were not changed, aPTT was elevated to about 10% above the upper limit of normal after the highest single dose only. Thrombin clotting time was prolonged after administration of high dose Solulin (10, 30 mg). No effect on in vitro bleeding time has been found. There was no evidence of bleeding risk with Solulin administration. The pharmacodynamic effects correlated with Solulin plasma concentrations. This demonstrates that the antithrombotic effect of Solulin is predictable, suggesting that patient monitoring is not expected. The results of this study provide evidence that Solulin can be expected to be an effective and safe anticoagulant, and further clinical investigation is warranted.

NXY-059 does not affect bleeding time in healthy volunteers: a randomized, double-blind, placebo-controlled, 3-period crossover phase I study.

NXY-059 is a novel free radical-trapping neuroprotectant that reduces infarct size and preserves brain function in animal models of acute ischemic stroke. It is the first neuroprotectant to demonstrate a reduction in global disability in a phase III clinical trial, as measured by the modified Rankin Scale. Any effect of NXY-059 on hemostasis may be important when treating stroke patients. This phase I randomized, double-blind, placebo-controlled, 3-period crossover study compared the effect of NXY-059, desmopressin, and placebo on bleeding time, platelet aggregation, and adhesion in 30 healthy volunteers. NXY-059 did not prolong bleeding time compared with placebo: mean (SD) time for NXY-059, 369.5 seconds (125.0 seconds) versus placebo, 369.1 seconds (136.0 seconds). There were no significant effects on platelet aggregation or adhesion. At a mean unbound plasma concentration (Cu(ss)) of 335 micromol/L, NXY-059 was well tolerated, with no major safety concerns identified. In conclusion, NXY-059 does not appear to affect primary hemostasis.

NXY-059 does not significantly interact with furosemide in healthy volunteers.

NXY-059 is a free radical-trapping neuroprotectant that reduces infarct size and preserves brain function in animal models of acute ischemic stroke. Acute ischemic stroke patients receiving NXY-059 may also be exposed to diuretics for treatment of heart failure or hypertension. NXY-059 and furosemide are partly eliminated by active tubular secretion via an organic anion transporter. This double-blind, randomized, crossover, placebo-controlled study investigated whether an infusion of NXY-059 (15 mg/mL) during 12 hours affects the diuretic and saluretic effects of a 30-mg intravenous bolus dose of furosemide (10 mg/mL) administered after 6 hours' infusion, in 13 male and 11 female healthy subjects. The net increase in urine volume and sodium excretion in the interval of 6 to 12 hours was 4.15 L and 178 mmol/L, respectively, during NXY-059 treatment (P = .93) and 4.34 L and 190 mmol/L, respectively, during placebo treatment (P = .54). NXY-059 reduced the renal clearance of furosemide by 19% (P = .019), and furosemide reduced the renal clearance of NXY-059 by 8% (P = .005). NXY-059 was well tolerated.

Safety, tolerability and pharmacokinetics of escalating doses of NXY-059 in healthy young and elderly subjects.

OBJECTIVE: NXY-059 is a novel, free-radical trapping, neuroprotectant that reduces infarct size and preserves brain function in animal models of acute ischaemic stroke. This study evaluated the safety, tolerability and pharmacokinetics of NXY-059 in the unbound steady-state plasma concentration (Cu(ss)) exposure range of 50-300 micromol/L in healthy young and elderly subjects. RESEARCH DESIGN AND METHODS: The primary objective of this two-centre, randomised, double-blind, placebo-controlled, dose-escalating study was to investigate the safety and tolerability, including renal function parameters and vasoirritative effects, of 8-h and 72-h intravenous infusions of NXY-059 in healthy young (20-45 years) and elderly (55-75 years) male and female subjects. The secondary objective of the study was to evaluate the pharmacokinetics of 8-h and 72-h intravenous infusions of NXY-059 in these subjects, using blood and urine samples taken during and after NXY-059 infusion as well as the doses administered. RESULTS: Of the 104 healthy volunteers who participated in the study, 72 were young and 32 were elderly. The type and incidence of adverse events in NXY-059 and placebo subjects were similar, although headache was more common in the NXY-059 group. Renal function was not altered in either group. Thrombophlebitis was reported in two elderly subjects: one receiving NXY-059 and one receiving placebo. A proportional relationship between AUC and dose for the 8-h and 72-h infusions was observed, and clearance did not change with dose. CONCLUSIONS: NXY-059 was well tolerated at all plasma concentrations tested in both the young and elderly subjects, and no safety concerns were raised. Linear pharmacokinetics were observed following 8-h and 72-h infusions of NXY-059 at doses resulting in an average Cu(ss) in the 52-317 micromol/L range.

Polymorphic drug metabolism (CYP2D6) and utilisation of psychotropic drugs in hospitalised psychiatric patients: a retrospective study.

AIM: The aim of the current retrospective study was to assess the influence of polymorphic drug metabolism as assessed by genotyping, on the on the utilisation of psychotropic drugs in hospitalised psychiatric patients. The utilisation of psychotropic drugs was assessed using pharmacy records with emphasis on the number of prescriptions and prescriptions for possible side effects. METHODS: CYP2D6 genotype was assessed in 241 psychiatric patients by investigation for the five most common allelic variants ( CYP2D6*3, *4, *6, *7, *8) and the presence of gene duplication using allele-specific polymerase chain reaction. Data concerning the pharmacotherapy of the patients were retrieved from the pharmacy information system. Data was analysed on differences observed in pharmacy records concerning the different metabolic classes: ultra rapid metabolisers (UMs), extensive metabolisers (EMs) and poor metabolisers (PMs). RESULTS: For CYP2D6, 2.5% was UM (95% CI: 0.5-4.5%, n=6) and 8.3% was PM (95% CI: 4.8-11.8%, n=20). Drugs metabolised by CYP2D6 were less frequently prescribed in PMs than EMs (21.1% vs 33.6%, P=0.023). The average duration of prescriptions was significantly lower in PMs than EMs (54 days vs 106 days, P=0.010). Between UMs and EMs, no significant differences were found, although a similar tendency was observed. With regard to dose, no consistent differences were observed between the CYP2D6 genotype classes. Drugs against Parkinsonian-like side effects were given twice as frequently in PMs as EMs (6.9% vs 3.4%, P=0.045). CONCLUSIONS: Patients with impaired CYP2D6 metabolism received fewer CYP2D6 drugs. PMs were more prone to Parkinsonian-like side effects as evidenced by more prescriptions for drugs combating these side effects. Dose titrations were not often used to compensate for genetic polymorphisms. Pharmacy records might be a useful tool to detect differences related to polymorphic metabolism.