Four-period Crossover Research Articles

The effects of selected sedatives on basal and stimulated serum cortisol concentrations in healthy dogs.

Hormone assessment is typically recommended for awake, unsedated dogs. However, one of the most commonly asked questions from veterinary practitioners to the endocrinology laboratory is how sedation impacts cortisol concentrations and the adrenocorticotropic hormone (ACTH) stimulation test. Butorphanol, dexmedetomidine, and trazodone are common sedatives for dogs, but their impact on the hypothalamic-pituitary-adrenal axis (HPA) is unknown. The objective of this study was to evaluate the effects of butorphanol, dexmedetomidine, and trazodone on serum cortisol concentrations. Twelve healthy beagles were included in a prospective, randomized, four-period crossover design study with a 7-day washout. ACTH stimulation test results were determined after saline (0.5 mL IV), butorphanol (0.3 mg/kg IV), dexmedetomidine (4 µg/kg IV), and trazodone (3-5 mg/kg PO) administration. Compared to saline, butorphanol increased basal (median 11.75 µg/dL (range 2.50-23.00) (324.13 nmol/L; range 68.97-634.48) vs 1.27 µg/dL (0.74-2.10) (35.03 nmol/L; 20.41-57.93); P < 0.0001) and post-ACTH cortisol concentrations (17.05 µg/dL (12.40-26.00) (470.34 nmol/L; 342.07-717.24) vs 13.75 µg/dL (10.00-18.90) (379.31 nmol/L; 275.96-521.38); P ≤ 0.0001). Dexmedetomidine and trazodone did not significantly affect basal (1.55 µg/dL (range 0.75-1.55) (42.76 nmol/L; 20.69-42.76); P = 0.33 and 0.79 µg/dL (range 0.69-1.89) (21.79 nmol/L; 19.03-52.14); P = 0.13, respectively, vs saline 1.27 (0.74-2.10) (35.03 nmol/L; 20.41-57.93)) or post-ACTH cortisol concentrations (14.35 µg/dL (range 10.70-18.00) (395.86 nmol/L; 295.17-496.55); (P = 0.98 and 12.90 µg/dL (range 8.94-17.40) (355.86 nmol/L; 246.62-480); P = 0.65), respectively, vs saline 13.75 µg/dL (10.00-18.60) (379.31 nmol/L; 275.86-513.10). Butorphanol administration should be avoided prior to ACTH stimulation testing in dogs. Further evaluation of dexmedetomidine and trazodone's effects on adrenocortical hormone testing in dogs suspected of HPA derangements is warranted to confirm they do not impact clinical diagnosis.

Effects of smartphone use while walking on external knee abduction moment peak: A crossover randomized trial on an instrumented treadmill

IntroductionIn addition to its effects on cognitive awareness, smartphone use while walking may reduce the speed, regularity, and symmetry of walking. Although its effects on spatiotemporal gait parameters, such as walking speed and step width, have already been studied, little is currently known about the impact of smartphone dual tasking on lower limb kinetics. Research questionDoes smartphone use during walking alter gait patterns (i.e., walking speed and step width) and consequently external knee moments? MethodsIn a four-period crossover trial, external knee moment peaks, walking speed, and step width were assessed in 27 healthy adults during matched-speed walking, self-paced walking, self-paced walking with spoken calculation tasks, and self-paced walking with smartphone-entered calculation tasks. Differences between the smartphone use condition and all other conditions were determined using repeated measures ANOVA with predefined contrasts. ResultsDecreased walking speed and increased step width were observed during smartphone use. The mean external knee abduction moment peak (Nm/kg) differed significantly (p < 0.01) across the intervention condition, namely walking with smartphone-entered calculations (0.15; 95 % CI: 0.12, 0.18), and the control conditions, namely matched-speed walking (0.11; 95 % CI: 0.08, 0.13), self-paced walking (0.11; 95 % CI: 0.09, 0.14), and walking with spoken calculations (0.14; 95 % CI: 0.12, 0.16). After confounder adjustment for walking speed, step width, gender, and age, this primary outcome was significantly different between using the smartphone and self-paced walking (p < 0.01, r = 0.51). This effect size was reduced when comparing smartphone use with spoken calculations (p = 0.04, r = 0.32). ConclusionWhen using a smartphone while walking, walking speed is slowed down, step width is increased, and knee moments are adversely altered compared to walking without dual tasking. These altered knee moments are partially, but not entirely, attributable to the cognitive calculation task. These effects are age-independent, but women are more affected than men. Nevertheless, it remains unclear whether sustained walking while using a smartphone adversely affects the development of knee joint pathologies.

Bioequivalence of two oral formulations of tebipenem pivoxil hydrobromide in healthy subjects.

Tebipenem pivoxil hydrobromide (TBP‐PI‐HBr) is a novel oral carbapenem prodrug of tebipenem (TBP), the active moiety, currently in development for treating serious bacterial infections. This study assessed the bioequivalence (BE) of the clinical trial and registration tablet formulations of TBP‐PI‐HBr and evaluated the effect of food on the pharmacokinetics (PKs) of tebipenem. This was a single center, open‐label, randomized, single‐dose, three‐sequence, four‐period crossover, BE, and food‐effect study. Subjects received single 600 mg oral doses of TBP‐PI‐HBr as the reference clinical trial tablet (treatment A) and test registration tablet (treatment B) formulations in alternating sequence while fasting, and then the test formulation under fed conditions. Whole blood samples were collected predose and at specified intervals up to 24 h postdose to evaluate TBP PK parameters. Safety and tolerability were monitored. Thirty‐six healthy, adult subjects were enrolled and completed the study. The criteria for BE were met for the TBP‐PI‐HBr test (registration tablet) and reference (clinical trial tablet) formulations as the 90% confidence intervals for the geometric mean ratios for TBP area under the curve (AUC)0‐t , AUC0‐inf, and maximum plasma concentration (C max) fell within the established 80% to 125% BE limits. Dosing with food had no meaningful effect on TBP PK parameters. Five (14%) subjects reported adverse events (AEs) of mild severity. No deaths, serious AEs, or discontinuations due to AEs were reported, and no clinically relevant electrocardiograms, vital signs, or safety laboratory findings were observed. The study results demonstrate the BE of oral TBP‐PI‐HBr registration and clinical trial tablet formulations and indicate that TBP‐PI‐HBr can be administered without regard to meals.

Biorelevant In Vitro Skin Permeation Testing and In Vivo Pharmacokinetic Characterization of Lidocaine from a Nonaqueous Drug-in-Matrix Topical System

Recently, lidocaine topical systems utilizing nonaqueous matrices have been developed and provide efficient lidocaine delivery through the skin, such that lower concentrations of drug provide equivalent or greater drug delivery than drug-in-matrix hydrogel lidocaine patches. This study characterizes drug delivery from a nonaqueous lidocaine topical system with increasing drug load both in vitro and in vivo. Topical systems formulated with either 1.8% or 5.4% lidocaine were applied to healthy volunteers’ backs (n = 15) for 12 h in a single-center, open-label, four-treatment, four-period crossover pharmacokinetic study. Subjects were dosed with either three 1.8% systems or one, two, or three 5.4% systems in each period. Blood was collected for up to 48 h, and plasma lidocaine levels were measured with a validated HPLC method. In parallel, human and mouse skin models characterized the in vitro skin permeation profile. The pharmacokinetic profile was linear between one, two, and three lidocaine 5.4% applications. Application of three lidocaine 1.8% systems (108 mg lidocaine) was bioequivalent to one lidocaine 5.4% system (108 mg lidocaine). Both topical systems remained well adhered to the skin and irritation was mild. The 5.4% system had approximately threefold higher skin permeability than the 1.8% system in the mouse and human skin models. The results indicate increasing the drug load by three times results in triple the drug delivery both in vivo and in vitro. The relationship between the in vitro permeation and in vivo absorption correlates and is nonlinear.

Relationship between antofloxacin concentration and QT prolongation and estimation of the possible false-positive rate

PurposeTo elucidate the relationship between antofloxacin (AT) plasma concentration and QT interval prolongation, compare the effects of different correction and analytical methods on conclusions, and estimate the possible false-positive rate in thorough QT (TQT) studies. MethodsTwenty-four healthy Chinese volunteers from a four-period crossover TQT study orally received 200 mg/d AT, 400 mg/d AT, 400 mg/d moxifloxacin, and a placebo in a random order for 5 d for each. QT interval samples were collected on d 1 and d 5. Population models were established describing the relationship between QT and AT concentration. The yardstick from ICH E14 guidelines was used to measure the effect of drugs on QT prolongation both in biostatistical and modeling analyses. A possible false-positive rate was estimated by constructing a 1000-time bootstrap to obtain the rate-of-difference values between d 1 and d 5 over 5 ms in the placebo period. ResultsIn the modeling analysis, the QT prolongation estimate at the mean maximal concentration of AT (4.51 μg/mL) was 3.84 ms, and its upper bound of the one-sided 95 % CI was 7.04 ms, which showed a negative effect on QT interval prolongation. The estimation for the false-positive rate was 31 % in this study. ConclusionThe effect of AT on QT interval prolongation may not have been significant at the dosage of 400 mg. Baseline and placebo adjustments were necessary in TQT studies. Population modeling has demonstrated clear superiority in making full use of data to accurately analyze the relationship between drugs and QT intervals.

Randomized controlled trial assessing plaque removal of an oscillating-rotating electric toothbrush with micro-vibrations

The objective was to assess plaque removal potential of a newly designed oscillating-rotating (O-R) electric rechargeable toothbrush with micro-vibrations compared to a manual toothbrush. This was a randomized single-brushing, two-treatment, examiner-blind, replicate-use, four-period crossover design study, conducted with three cohorts of nine subjects each, with all subjects using each toothbrush twice. Test toothbrushes included a new O-R rechargeable electric toothbrush with micro-vibrations (Oral-B iO prototype) and a manual American Dental Association (ADA) reference toothbrush. On each of the four study visits, subjects refrained from oral hygiene for 12hours prior. At each visit, subjects received a pre-brushing plaque examination, brushed with their assigned toothbrush and a marketed fluoride dentifrice and then received a post-brushing plaque examination. Plaque was assessed using the expanded Turesky Modified Quigley-Hein Plaque Index. Treatment comparison analyses were two-sided and carried out at the 5% significance level. All 27 randomized subjects (mean age = 42.0years) completed the trial. Both brushes produced significant plaque reductions versus baseline (P<0.001). The O-R electric brush provided statistically significantly greater plaque reductions in all regions compared to the regular manual toothbrush, with a between-treatment difference of 0.929 for whole mouth plaque, 0.965 for proximal plaque, 1.029 for lingual plaque and 0.815 for facial plaque (P<0.001 for all comparisons). Additionally, use of the novel O-R brush yielded greater brushing evenness/consistency when comparing the facial and lingual mean plaque removal differences relative to manual brushing (P=0.001). Both brushes were well-tolerated. The novel O-R toothbrush with micro-vibrations produced significantly greater plaque reductions compared to the manual toothbrush.

Testing treatment-by-period interaction in four-period crossover trials.

Statistical analyses of crossover clinical trials have mainly focused on assessing the treatment effect, carryover effect, and period effect. Whena treatment-by-period interaction is plausible, it is important to test such interaction first before making inferences on differences among individual treatments. Considerably less attention has been paid to the treatment-by-period interaction, which has historically been aliased with the carryover effect in two-period or three-period designs. In this article, from the data of a newly developed four-period crossover design, we propose a statistical method to compare the effects of two active drugs with respect to two response variables. We study estimation and hypothesis testing considering the treatment-by-period interaction. Constrained least squares is used to estimate the treatment effect, period effect, and treatment-by-period interaction. For hypothesis testing, we extend a general multivariate method for analyzing the crossover design with multiple responses. Results from simulation studies have shown that this method performs very well. We also illustrate how to apply our method to the real data problem.

Sample size re-estimation in crossover trials: application to the AIM HY-INFORM study

BackgroundCrossover designs are commonly utilised in randomised controlled trials investigating treatments for long-term chronic illnesses. One problem with this design is its inherent repeated measures necessitate the availability of an estimate of the within-person standard deviation (SD) to perform a sample size calculation, which may be rarely available at the design stage of a trial. Interim sample size re-estimation designs can be used to help alleviate this issue by adapting the sample size mid-way through the trial, using accrued information in a statistically robust way.MethodsThe AIM HY-INFORM study is part of the Informative Markers in Hypertension (AIM HY) Programme and comprises two crossover trials, each with a planned recruitment of 600 participants. The objective of the study is to test whether blood pressure response to first line antihypertensive treatment depends on ethnicity. An interim analysis is planned to reassess the assumptions of the planned sample size for the study. The aims of this paper are: (1) to provide a formula for sample size re-estimation in both crossover trials; and (2) to present a simulation study of the planned interim analysis to investigate alternative within-person SDs to that assumed.ResultsThe AIM HY-INFORM protocol sample size calculation fixes the within-person SD to be 8 mmHg, giving > 90% power for a primary treatment effect of 4 mmHg. Using the method developed here and simulating the interim sample size reassessment, if we were to see a larger within-person SD of 9 mmHg at interim, 640 participants for 90% power 90% of the time in the three-period three-treatment design would be required. Similarly, in the four-period four-treatment crossover design, 602 participants would be required.ConclusionsThe formulas presented here provide a method for re-estimating the sample size in crossover trials. In the context of the AIM HY-INFORM study, simulating the interim analysis allows us to explore the results of a possible increase in the within-person SD from that assumed. Simulations show that without increasing the planned sample size of 600 participants, we can reasonably still expect to achieve 80% power with a small increase in the within-person SD from that assumed.Trial registrationClinicalTrials.gov, NCT02847338. Registered on 28 July 2016.

Pharmacokinetics of Salmeterol and Fluticasone Propionate Delivered in Combination via Easyhaler and Diskus Dry Powder Inhalers in Healthy Subjects.

Background: Easyhaler® dry powder inhaler (DPI) containing salmeterol and fluticasone propionate was developed for the treatment of asthma and chronic obstructive pulmonary disease. Three different Salmeterol/fluticasone Easyhaler test products (Orion Pharma, Finland) were compared against the reference product Seretide® Diskus® DPI (GlaxoSmithKline, United Kingdom) to study whether any of the test products are bioequivalent with the reference.Methods: Open and randomized pharmacokinetic four-period crossover study on 65 healthy volunteers was performed in a single center to compare the lung deposition and total systemic exposure of salmeterol and fluticasone propionate after administration of single doses (two inhalations of 50/500 μg/inhalation strength) in fasting conditions. Blood samples were drawn before dosing and at frequent time points between 2 minutes and 34 hours after dosing for determination of drug concentrations. The primary variables for total systemic exposure and lung deposition of fluticasone propionate were maximum concentration of the concentration–time curve (Cmax) and area under the concentration–time curve from time zero to the last sample with quantifiable concentration (AUCt). For salmeterol, the primary variables for total systemic exposure were Cmax and AUCt and for lung deposition Cmax and AUC up to 30 minutes after study treatment administration (AUC30min).Results: One of the Easyhaler test products met all the criteria for bioequivalence with the reference. The 96.7% confidence intervals (CIs) for the test/reference ratios of fluticasone propionate Cmax and AUCt were 0.9901–1.1336 and 0.9448–1.0542, respectively. Ninety percent CIs for salmeterol Cmax, AUC30min, and AUCt ratios were 1.0567–1.2012, 1.0989–1.2255, and 1.0769–1.1829, respectively. Median salmeterol time to maximum concentration (tmax) was 4.0 minutes. Median fluticasone propionate tmax was from 1.5 to 2.0 hours. Terminal elimination half-life was 11 hours for salmeterol and 9–10 hours for fluticasone propionate.Conclusions: Salmeterol/fluticasone Easyhaler was shown to be bioequivalent with the reference product.

Effect of phytate and zinc ions on fluoride toothpaste efficacy using an in situ caries model

ObjectivesTo compare and explore the dose-response of phytate-containing 1150 ppm fluoride toothpastes on model caries lesions and to determine the impact of zinc ions. MethodsThis was a single-centre, randomised, blinded (examiner/laboratory analyst), six-treatment, four-period crossover, in situ study in adults with a removable bilateral maxillary partial denture. Study treatments were toothpastes containing: 0.425% phytate/F; 0.85% phytate/F; 0.85% phytate/Zn/F; F-only; Zn/F and a 0% F placebo. Where present, F was 1150 ppm as NaF; Zn was 0.3% as ZnCl2. Human enamel specimens containing early-stage, surface-softened (A-lesions) or more advanced, subsurface (B-lesions) caries lesions were placed into the buccal flanges of participants’ modified partial denture (one of each lesion type per side). A-lesions were removed after 14 days of twice-daily treatment use; B-lesions were removed after a further 14 days. A-lesions were analysed for surface microhardness recovery. Both lesion types were analysed by transverse microradiography and for enamel fluoride uptake, with B-lesions additionally analysed by quantitative light-induced fluorescence. Comparison was carried out using an analysis of covariance model. ResultsStatistically significant differences between 1150 ppm F and the placebo toothpastes (p < 0.05) were shown for all measures, validating the model. No differences between fluoride toothpastes were observed for any measure with little evidence of a dose-response for phytate. Study treatments were generally well-tolerated. ConclusionsResults suggest phytate has little impact on fluoride’s ability to promote early-stage lesion remineralisation or prevent more advanced lesion demineralisation in this in situ caries model. Similarly, results suggest zinc ions do not impair fluoride efficacy. Clinical significanceToothpastes may contain therapeutic or cosmetic agents that could interfere with fluoride’s caries prevention efficacy. The present in situ caries study has demonstrated that phytate, added to provide enhanced extrinsic stain removal/prevention, and zinc, added to inhibit malodour, do not impair fluoride efficacy.

The pharmacokinetics, safety, and tolerability of single, high-strength doses of fluticasone propionate and fluticasone propionate/salmeterol delivered via a novel multidose dry powder inhaler in adolescents and adults with persistent asthma

ABSTRACTObjective: Characterize fluticasone propionate (Fp) and combination fluticasone propionate and salmeterol (FS) pharmacokinetic and safety profiles, delivered via a novel, inhalation-driven, multidose dry powder inhaler (MDPI). Methods: This multicenter, open-label, four-period crossover, single-dose study randomized patients aged ≥12 years with persistent asthma to Fp MDPI 200 mcg, FS MDPI 200/12.5 mcg, Fp dry powder inhaler (DPI) 500 mcg (250 mcg × 2 inhalations), or FS DPI 500/50 mcg. Blood samples for determination of Fp and salmeterol pharmacokinetic parameters including Cmax, AUC0–t, AUC0–inf, tmax, and t½ were collected predose through 36 h postdose (14 time points). Safety assessments comprised adverse events, vital signs, and physical examinations. The institutional review board approved the study protocol. Results: The pharmacokinetic analysis set and safety population each included 40 patients. Fp systemic exposure (Cmax, AUC0–t, and AUC0–inf) was highest for Fp DPI 500 mcg and similar for Fp MDPI 200 mcg, FS MDPI 200/12.5 mcg, and FS DPI 500/50 mcg. Fp geometric mean t½ values were similar across treatments. Salmeterol Cmax was 20% lower and AUC0–t and AUC0–inf were approximately 50% lower with FS MDPI versus FS DPI. Median tmax and geometric mean t½ were similar between FS MDPI and FS DPI. Adverse events were similar across treatments with no relevant changes in vital signs, physical examinations, or hematology test results. Conclusions: Fp MDPI and FS MDPI produced similar or lower systemic exposure to Fp and salmeterol, despite lower doses, versus conventional DPI devices, suggesting improved efficiency due to formulation and device differences.

Effects of three major amino acids found in Japanese broth on glucose metabolism and gastric emptying.

To our knowledge, the effect of the broth of dried kelp and dried bonito, dashi, on glucose metabolism and digestion has rarely been studied. Based on the component analysis of three actual broths served in traditional restaurants, a chemically synthesized broth with three free amino acids (histidine, glutamate, aspartate) and salt was prepared to investigate their effect on glucose metabolism, glucose-dependent insulinotropic polypeptide (GIP), and glucagon-like peptide 1 (GLP-1) secretion, and digestion. In study 1, seven healthy individuals were enrolled in a four-period crossover study. Participants drank or ate hot water, synthesized broth, hot water with rice, and synthesized broth with rice. Plasma glucose, serum insulin, plasma glucagon, plasma GIP, and plasma GLP-1 were measured at baseline and after ingestion. In study 2, 6 of the 7 individuals ingested rice steamed with 13C-labeled sodium acetate with hot water or synthesized broth to estimate gastric emptying by the 13C-labeled acetate breath test in a two-period crossover trial. Ingesting water or synthesized broth alone elicited no change in plasma glucose or serum insulin levels. Ingesting synthesized broth with rice resulted in a rapid rise in plasma glucose and GLP-1 (P=0.01 and 0.02, respectively) in an early postprandial phase compared with that by ingesting water with rice, but the area under the curve of those showed no significant differences. Ingesting synthesized broth with rice resulted in a significantly higher gastric emptying coefficient than that after rice with water (P=0.03). Three amino acids and sodium chloride corresponding to those found in actual broth promoted gastric emptying and led to a rapid response of plasma glucose. Our findings suggest that ingestion of the broth of dried kelp and dried bonito may improve gastric motility.

Population pharmacokinetics of moxifloxacin and its concentration-QT interval relationship modeling in Chinese healthy volunteers.

Moxifloxacin (MX) is an 8-methoxyquinolone antimicrobial drug, which is often used as a positive control in thorough QT (TQT) studies. In the present study we established the population pharmacokinetics model of MX and the relationship of MX concentrations with the QT and various corrected QT (QTc) intervals, and compared the results with other ethnicities. The MX data used for modeling were obtained from a published TQT interval prolongation study of antofloxacin with MX as the positive control. In this four-period crossover study, 24 adult Chinese healthy volunteers received either 200 or 400 mg of oral antofloxacin once daily, 400 mg of MX, or a placebo. Population concentration-effect models were used to investigate the relationship between MX concentrations and QT interval prolongation, baseline-adjusted QTc (ΔQTc), or ΔQTc adjusted with time-matched placebo corrections (ΔΔQTc). The influencing factors of MX PK and the concentration-QTc relationship were determined through covariate screening. Simulation studies were conducted in R2.30 by using the final model with the estimated population mean and intra-individual and inter-individual variability. The estimated pharmacokinetic parameters and the estimated slope of the MX concentration-QT/ΔQTc/ΔΔQTc relationship were described using models and were compared to results for other ethnicities from the literature. We showed that the population pharmacokinetic parameter estimates for total plasma clearance (CL/F), the volume of distribution of central compartment (Vc/F), the distributional clearance in plasma (Q), the volume of distribution of peripheral compartment (Vp/F), and the absorption rate constant (Ka) were 8.22 L/h, 104 L, 3.98 L/h, 37.7 L, and 1.81 1/h, respectively. There was no significant covariate included in the final model. QT interval prolongation of MX estimates ranging from 9.77 to 12.91 ms at the mean average maximum concentration of MX (4.36 μg/mL) and a mean slope ranging from 2.33 to 2.96 ms per μg/mL. In conclusion, no ethnic differences were observed for the MX pharmacokinetic parameters and QT interval prolongation.

Bronchodilator efficacy of extrafine glycopyrronium bromide: the Glyco 2 study.

An extrafine formulation of the long-acting muscarinic antagonist glycopyrronium bromide (GB) is in development for chronic obstructive pulmonary disease (COPD), in combination with beclometasone dipropionate and formoterol fumarate – a “fixed triple”. This two-part study was randomized, double blind, placebo controlled in patients with moderate-to-severe COPD: Part 1: single-dose escalation, GB 12.5, 25, 50, 100 or 200 μg versus placebo; Part 2: repeat-dose (7-day), four-period crossover, GB 12.5, 25 or 50 μg twice daily (BID) versus placebo, with an open-label extension in which all patients received tiotropium 18 μg once daily. On the morning of Day 8 in all five periods, patients also received formoterol 12 μg. In study Part 1, 27 patients were recruited. All GB doses significantly increased from baseline forced expiratory volume in 1 second (FEV1) area under the curve (AUC0–12h) and peak FEV1, with a trend toward greater efficacy with higher GB dose. All adverse events were mild–moderate in severity, with a lower incidence with GB than placebo and no evidence of a dose–response relationship. In study Part 2, of 38 patients recruited, 34 completed the study. Adjusted mean differences from placebo in 12 h trough FEV1 on Day 7 (primary) were 115, 142 and 136 mL for GB 12.5, 25 and 50 μg BID, respectively (all P<0.001). GB 25 and 50 μg BID were superior (P<0.05) to GB 12.5 μg BID for pre-dose morning FEV1 on Day 8. For this endpoint, GB 25 and 50 μg BID were also superior to tiotropium. Compared with Day 7, addition of formoterol significantly increased Day 8 FEV1 peak and AUC0–12h with all GB doses and placebo (all P<0.001). All adverse events were mild–moderate in severity and there was no indication of a dose-related relationship. This study provides initial evidence on bronchodilation, safety and pharmacokinetics of extrafine GB BID. Overall, the results suggest that GB 25 μg BID is the optimal dose in patients with COPD.

Comparison of low frequency repetitive transcranial magnetic stimulation parameters on motor cortex excitability in normal subjects

Background/objectivesOptimal low frequency repetitive transcranial magnetic stimulation (LF-rTMS) parameters for treating epilepsy and other brain disorders are unknown. To address this question, a systematic study of the effects of LF-rTMS frequency and intensity on cortical excitability was performed. MethodsUsing a four-period crossover design, subjects were scheduled for four LF-rTMS sessions that were at least four weeks apart. LF-rTMS was delivered as 900 pulses directed at primary motor cortex using four protocols: 0.5Hz at 90% resting motor threshold (RMT), 0.5Hz at 110% RMT, 1Hz at 90% RMT, and 1Hz at 110% RMT. Motor evoked potential (MEP) amplitude, resting motor threshold (RMT), and cortical silent period (CSP) were measured before, immediately after, and 60min after LF-rTMS. Each of the four protocols was analyzed separately to compare baseline measurements to those after LF-rTMS. ResultsNone of the four LF-rTMS protocols produced a trend or significant change in MEP amplitude, RMT, or CSP. ConclusionThe lack of significant effect from the four LF-rTMS protocols indicates that none produced evidence for alteration of cortical excitability. The direct comparison of four LF-rTMS protocols is distinct to this investigation, as most similar studies were exploratory and studied only one or two protocols. The negative result relates only to the methods used in this investigation and does not indicate that LF-rTMS does not alter cortical excitability with other parameters. These results may be useful when designing additional investigations into the effect of LF-rTMS on epilepsy, other disorders, and cortical excitability.

Pharmacokinetic properties of low-dose SoluMatrix meloxicam in healthy adults.

SoluMatrix® meloxicam has been developed using SoluMatrix Fine Particle Technology™ to produce a meloxicam drug product with enhanced absorption properties to enable treatment at lower doses than available oral meloxicam drug products. This follows recognition of serious dose-dependent adverse events (AEs) associated with nonsteroidal anti-inflammatory drugs, including meloxicam. This study investigated the pharmacokinetic (PK) properties of SoluMatrix meloxicam 5-mg (fasting conditions) and 10-mg capsules (fasting and fed conditions) and compared SoluMatrix meloxicam 10-mg capsules with meloxicam 15-mg tablets under fasting conditions. This four-period crossover study randomized 28 healthy adult participants to receive single doses of SoluMatrix meloxicam 5-mg capsules (fasting) and 10-mg capsules (fasting or fed) and meloxicam tablets 15mg (fasting). Meloxicam plasma concentrations were assessed through 96h postdose. Safety was assessed. Twenty-five participants (89.3%) completed the study. Under fasting conditions, SoluMatrix meloxicam 10mg [1252.8 (254.22) ng/mL] produced similar meloxicam mean (standard deviation (SD)) maximum plasma concentrations vs meloxicam 15-mg tablets [1288.8 (424.40) ng/mL]. The overall mean (SD) systemic meloxicam exposure was 33% lower for SoluMatrix meloxicam 10mg [29,173.01 (11,042.09) ng*h/mL] vs meloxicam 15-mg tablets [40,875.6 (11,733.47) ng*h/mL]. The median time to maximum plasma meloxicam levels occurred earlier following SoluMatrix meloxicam 5mg (2.0h) and 10mg (2.0h) administration vs meloxicam 15-mg tablets (4.0h). Few study-medication-related AEs were reported. SoluMatrix meloxicam 10mg was more rapidly absorbed and associated with a lower overall exposure compared with meloxicam 15-mg tablets in this study in healthy adults under fasting conditions.

Effects of two calculolytic diets on parameters of feline mineral metabolism.

To evaluate the influence of two feline calculolytic diets on selected parameters of mineral metabolism. Two dry commercial diets designed for struvite urolith dissolution were evaluated in 14 cats. The study was designed as a two-sequence, four-period crossover protocol with a baseline period, two 60-day "run-in" periods in which calculolytic diets (Diet 1 and Diet 2) were fed and one 30-day "wash-out" period. Data are expressed as median (range). Feeding the calculolytic diets for two months did not alter plasma concentrations of calcium, phosphorus, magnesium and parathyroid hormone. A significant (P < 0.05 in each case) decline in calcitriol was observed after administering both diets from 236.4 (122.4-429.6) to 170.4 (108.0-394.3) pmol/L (Diet 1) and from 278.4 (153.6-492.0) to 177.1 (87.6-392.4) pmol/L (Diet 2). Cats fed Diet 1 showed a significant increase in urine calcium concentration (from 0.3 (0.2-0.5) to 0.4 (0.3-0.7) mmol/L). Magnesium concentration in urine was significantly increased with both diets, from 1.4 (0.1-1.7) to 1.5 (1.3-2.4) mmol/L (Diet 1) and from 1.1 (0.4-1.9) to 2.0 (0.1-3.1) mmol/L (Diet 2). Both diets resulted in an increased urinary concentration of magnesium, through different mechanisms: urine acidification (Diet 1) and increased sodium load (Diet 2).

A phase 1, randomised, open-label, four-period crossover, single-dose study to evaluate the pharmacokinetics of hydrocortisone modified release tablets

A phase 1, randomised, open-label, four-period crossover, single-dose study to evaluate the pharmacokinetics of hydrocortisone modified release tablets

Pharmacokinetic/pharmacodynamic assessments of 10 mg/kg tramadol intramuscular injection in yellow-bellied slider turtles (Trachemys scripta scripta).

In reptiles, administration of opioid drugs has yielded unexpected results with respect to analgesia. The aims of this study were to assess the pharmacokinetic/pharmacodynamic (PK/PD) properties of tramadol and its active metabolite M1 and to evaluate the effect of the renal portal system on the PK/PD parameters in yellow-bellied slider turtles. Turtles (n = 19) were randomly assigned to four treatment groups, according to a masked, single-dose, four-treatment, unpaired, four-period crossover design. Group A (n = 5) received a single i.m. dose of tramadol (50 mg/mL) at 10 mg/kg in the proximal hindlimb. Group B (n = 5) received the same i.m. dose but in the forelimb. Groups C (n = 5) and D (n = 4) received a single i.m. injection of saline (NaCl 0.9%) of equivalent volume to the volumes of tramadol injected in the hind- and forelimb, respectively. Groups were rotated (1-month washout period) until the completion of the crossover study. Tramadol plasma concentrations were evaluated by a validated HPLC-FL method. An infrared thermal stimulus was applied to the plantar surface of the turtles' hindlimbs to evaluate the thermal withdrawal latency (TWL). The two PK profiles of tramadol differed in the first 2 h following administration, but overlapped in the elimination phases. The metabolite M1 was formed in both the treatment groups, showing similar pharmacokinetic trends, although the amount of M1 was significantly higher (20%) in the hindlimb vs. forelimb group. Turtles given tramadol in the hind- and forelimb showed a significant increase in TWL over the periods of 0.5-48 and 8-48 h, respectively. The calculated % maximal possible response (% MPR) was low (about 24%). The PK/PD correlations between M1 plasma concentrations vs. % MPR appeared to show a counterclockwise hysteresis loop shape.

A randomised clinical study to measure the anti-erosion benefits of a stannous-containing sodium fluoride dentifrice.

Background:To compare the enamel protection efficacy of stannous-containing sodium fluoride and sodium monofluorophosphate (MFP)/triclosan dentifrices marketed in India in an in situ erosion model with acidic challenge.Materials and Methods:This randomised and controlled, in situ, supervised, double-blind clinical trial employed a two-treatment, four-period crossover design, wherein subjects wore an appliance fitted with human enamel samples 6 h/day during each 10 day treatment period and swished twice daily with their assigned dentifrice slurry: Oral-B® Pro-Health (maximum 1,000 ppm F as sodium fluoride with stannous chloride) or Colgate® Strong Teeth with Cavity Protection (maximum 1,000 F as sodium MFP and triclosan). Subjects swished with 250 ml of orange juice over a 10 min period after each treatment and twice daily for the acidic erosive challenge. Enamel samples were measured for tooth surface loss using contact profilometry at baseline and day 10.Results:A total of 34 subjects were randomised to treatment; 32 subjects completed the final visit. Baseline profilometry measurements of the specimen surfaces were near zero within ± 0.3 μm, and no statistically significant difference (P > 0.48) on average was observed between the two test dentifrices. At day 10, the stannous-containing dentifrice demonstrated 88% less erosion (P < 0.0001) relative to the MFP/triclosan dentifrice. Estimated medians (95% confidence intervals) were 0.21 μm (0.17, 0.25) for the stannous-containing dentifrice versus 1.66 μm (1.39, 1.99) for the MFP/triclosan dentifrice. Both dentifrices were well-tolerated.Conclusions:Compared with MFP/triclosan toothpaste, a stabilised stannous-containing sodium fluoride dentifrice gave statistically significantly greater protection against tooth enamel surface loss in situ following repeated acid erosive challenge.