Three-way Crossover Study Research Articles

The use of betaine HCl to enhance dasatinib absorption in healthy volunteers with rabeprazole-induced hypochlorhydria.

Many orally administered, small-molecule, targeted anticancer drugs, such as dasatinib, exhibit pH-dependent solubility and reduced drug exposure when given with acid-reducing agents. We previously demonstrated that betaine hydrochloride (BHCl) can transiently re-acidify gastric pH in healthy volunteers with drug-induced hypochlorhydria. In this randomized, single-dose, three-way crossover study, healthy volunteers received dasatinib (100 mg) alone, after pretreatment with rabeprazole, and with 1500 mg BHCl after rabeprazole pretreatment, to determine if BHCl can enhance dasatinib absorption in hypochlorhydric conditions. Rabeprazole (20 mg b.i.d.) significantly reduced dasatinib Cmax and AUC0-∞ by 92 and 78%, respectively. However, coadministration of BHCl significantly increased dasatinib Cmax and AUC0-∞ by 15- and 6.7-fold, restoring them to 105 and 121%, respectively, of the control (dasatinib alone). Therefore, BHCl reversed the impact of hypochlorhydria on dasatinib drug exposure and may be an effective strategy to mitigate potential drug-drug interactions for drugs that exhibit pH-dependent solubility and are administered orally under hypochlorhydric conditions.

Glycopyrronium does not affect QT interval in healthy subjects: a randomized, three- period, cross-over, placebo- and positive-controlled study.

Glycopyrronium (NVA237), a once-daily long-acting muscarinic antagonist, has recently been approved for the treatment of patients with chronic obstructive pulmonary disease (COPD). This study evaluated the effect of glycopyrronium on the QT interval and other cardiac parameters in healthy subjects. This randomized, partially blinded, single-dose, placebo- and positive- (moxifloxacin) controlled, three-way cross-over study investigated the effect of a single inhaled supra-therapeutic dose (8-fold clinical dose in COPD patients) of 400 µg glycopyrronium on the Fridericia-corrected QT interval (QTcF; primary objective), Bazettcorrected QT interval (QTcB), heart rate, blood pressure, pharmacokinetics (PK), safety, and tolerability. A total of 73 healthy male (n = 35) and female (n = 38) subjects, aged between 18 and 45 years, were randomized. Glycopyrronium did not cause significant QTcF prolongation compared to placebo. The largest time-matched mean difference to placebo was 2.97 ms at 5 minutes, with the upper limit of the two-sided 90% confidence interval (CI) being 4.80 ms, excluding a relevant QT effect as defined by the ICH E14 guideline. Glycopyrronium had a slight bradycardic effect with a mean change of -2.88 (90% CI: -3.78, -1.99) beats per minutes (bpm) and a maximum of -5.87 (90% CI: -7.82, -3.92) bpm at 5 hours post-inhalation. No clinically relevant effects were seen on QTcB, other electrocardiogram (ECG) intervals, or blood pressure. Maximum plasma concentration (Cmax) of glycopyrronium was achieved shortly after inhalation (median tmax = 7 minutes). All the treatments were well tolerated with no serious adverse events. A supra-therapeutic dose of glycopyrronium had a favorable cardiovascular safety profile with no clinically relevant effect on QT interval.

Head-to-head, randomised, crossover study of oral versus subcutaneous methotrexate in patients with rheumatoid arthritis: drug-exposure limitations of oral methotrexate at doses ≥15 mg may be overcome with subcutaneous administration

ObjectiveTo compare the relative bioavailability, safety and tolerability of oral methotrexate (MTX) and subcutaneous (SC) MTX administered via an auto-injector (MTXAI) in patients with rheumatoid arthritis (RA).MethodsIn this randomised, multicenter,...

Drowsiness and motor responses to consecutive daily doses of promethazine and loratadine

ObjectivesLimited information is available regarding sedation and motor function following repeat dosing of antihistamines. This study examined how promethazine and loratadine affect day-time drowsiness, the commencement of voluntary movement, and involuntary movement when administered on consecutive days. MethodsTen healthy young subjects (24±5years) were recruited into a double-blind, placebo-controlled, three-way crossover study. Subjects ingested either promethazine, loratadine or a placebo, and ingested the same drug 24h later. Measures of drowsiness, simple reaction time (SRT), choice reaction time (CRT), and postural tremor were obtained pre-ingestion, 1h post-ingestion and 2h post-ingestion on each day. ResultsConsecutive daily doses of promethazine and loratadine affected SRT and CRT, respectively, whereby reaction time deficits were less pronounced following the repeat dose. A reduced tremor response was also observed following consecutive daily dosing of promethazine, in contrast to loratadine which caused an increase in tremor amplitude with the consecutive daily dose. ConclusionsReaction time and tremor responses differed following the single dose compared to consecutive doses. SignificanceSufferers of allergic rhinitis often require antihistamine dosing regimens that continue over multiple days. Future studies will benefit from examining drowsiness and movement responses following single doses as well as consecutive dosing.

Effect of lenvatinib (E7080) on the QTc interval: results from a thorough QT study in healthy volunteers

QT assessment of oncology drugs is generally challenging because they are genotoxic and, of necessity,they require multisite evaluation in cancer patients. Lenvatinib is not genotoxic, therefore, this thorough QT (TQT)study with lenvatinib, a multityrosine kinase inhibitor, was undertaken utilizing healthy volunteers and concentration effect modeling to project the TQT effect at high plasma levels. Fifty-two healthy subjects randomly received single doses of lenvatinib 32 mg, placebo, or moxifloxacin 400 mg in a three-way crossover study. Serial electrocardiograms were recorded, and the effect on placebo corrected change-from-baseline QTcF (ΔΔQTcF) was evaluated. The relationship between lenvatinib plasma concentrations and QTcF was analyzed with linear mixed effects modeling. L envatinib mildly lowered the heart rate by 5–8 bpm during the first 12 h after dosing. ΔΔQTcF was shortened with a peak effect of −5.72 ms (90 % confidence interval (90 % CI) −7.76 to −3.69 ms) at 6 h postdosing.The upper bound of mean ΔΔQTcF did not exceed 2 ms at any time point postdosing. A concentration-dependent effect of lenvatinib on ΔΔQTcF was identified with an estimated population intercept of −2.96 ms (90 % CI −4.49 to−1.43 ms; P = 0.0016) and a negative slope of −0.0045(90 % CI −4.49 to −1.43) ms per ng/mL, respectively. The safety profile after a single dose of lenvatinib was acceptable,with adverse events (AEs) of mild-to-moderate severity and no serious AEs. L envatinib had no clinically relevant effect on the QTc interval. Concentration-effect modeling supports the lack of QTc prolongation at high plasma concentrations.

Effects of a protein‐rich drink or a standard meal on the pharmacokinetics of elvitegravir, cobicistat, emtricitabine and tenofovir in healthy Japanese male subjects: A randomized, three‐way crossover study

This study investigated the effects of ingested food types on the pharmacokinetics of elvitegravir, cobicistat, emtricitabine, and tenofovir as a single-tablet regimen (STR) in Japanese HIV-negative healthy subjects. In this open-label, randomized, three-way crossover study, the pharmacokinetic profiles of elvitegravir, cobicistat, emtricitabine, and tenofovir were evaluated when administered with a standard breakfast, under fasting conditions, or with a nutritional protein-rich drink. All subjects (N = 11) received a single morning dose of elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil fumarate (150/150/200/300 mg). Administration under fasting conditions resulted in decreases in the mean AUCinf of elvitegravir and tenofovir by 50% and 28%, respectively, relative to administration with a standard breakfast, whereas the bioavailabilities of elvitegravir and tenofovir were comparable when administered with a standard breakfast or a nutritional protein-rich drink. Under fasting conditions, it appears that the bioavailabilities of elvitegravir and tenofovir were not equivalent to those when they were administered with either type of food, although they were bioequivalent to each other under fed conditions. Cobicistat and emtricitabine were bioequivalent under all conditions. These findings suggest that elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil fumarate should be administered with food, and that the bioavailability of elvitegravir and tenofovir is not affected by the type of meal ingested.

The effect of AST-120 on the single-dose pharmacokinetics of metoprolol extended-release tablets in healthy subjects

This was a randomized, open-label, three-way crossover study to assess the effects of AST-120 (an orally administered spherical carbon adsorbent acting in the gastrointestinal tract without systemic circulation) on the single-dose pharmacokinetics of metoprolol in an extended-release formulation (metoprolol ER) in healthy volunteers. A total of 34 subjects were singly administered metoprolol ER alone (A), and metoprolol ER in combination with AST-120 simultaneously (B) and 1 h later (C). The total exposure was more significantly reduced in both treatments B and C than that in treatment A; the geometric mean ratios of area under the curve extrapolated to infinity (AUC0-∞) for B/A and C/A were reduced by approximately 30% in both treatments B and C. Maximum observed plasma concentration (Cmax) of metoprolol in treatment B significantly decreased, whereas Cmax in treatment C was slightly decreased. AST-120 treatment was unlikely to affect apparent first-order terminal elimination half-life (T1/2) of metoprolol significantly. Reduction in heart rate and blood pressure readings were similar across the treatment periods. Coadministration of AST-120 and metoprolol ER was safe and was well tolerated. Because AST-120 reduced gastrointestinal absorption of metoprolol ER, careful monitoring of heart rate and blood pressure is recommended in coadministration of AST-120 with metoprolol ER.

A randomised, controlled, crossover study to investigate the safety and response of 1R,2S‐methoxamine hydrochloride (NRL001) on anal function in healthy volunteers

This study aimed to assess the dose and volume effects of suppository preparations and safety of NRL001 (one of four possible stereoisomers of methoxamine hydrochloride) on anal sphincter tone using rectal suppositories in healthy adult volunteers. This was a Phase I, single-centre, randomised, double-blind, three-way crossover study during which subjects received three single doses of 1 g rectal suppositories (containing 5 or 10 mg NRL001 or matching placebo) or 2 g rectal suppositories (containing 10 or 15 mg NRL001 or matching placebo) on three separate dosing days. The outcome measures were mean anal resting pressure (MARP) variables (monitored continuously for 20-30 min before and up to 6 h after dosing), pharmacokinetics (PK) and safety assessments. Twenty-six subjects were dosed with study medication. Two subjects were withdrawn prematurely and were not included in the main analysis. There was a dose-dependent increase in anal sphincter tone (MARP) when comparing the 5 and 10 mg doses of NRL001; however, the 15 mg dose did not have a significantly greater effect than the 10 mg dose. Suppository size (1 or 2 g) did not appear to have an effect on sphincter tone. There was no evidence against dose proportionality for the PK variables, but the mean maximum plasma concentration (Cmax ) for the 1 g suppository group was higher than for the 2 g group. Twenty-one adverse events were reported in 8 (30.8%) subjects. A dose dependent decrease in heart rate was noted; however, there were no adverse events reported that were related to this reduction in heart rate. The increase in anal sphincter tone supports the potential therapeutic use of NRL001 in treating faecal incontinence, with further studies in patients required. NRL001 was well tolerated in single doses of up to 15 mg.

Similar Maximum Systemic but not Local Cyclooxygenase-2 Inhibition by 50 mg Lumiracoxib and 90 mg Etoricoxib: A Randomized Controlled Trial in Healthy Subjects

Once daily doses of 100-400 mg lumiracoxib have been proposed to inhibit local prostaglandin synthesis longer than systemic prostaglandin synthesis due to local accumulation in inflamed, acidic tissue. Lower, less toxic doses, however, might still achieve the clinical goal and merit further contemplation. In a randomized, double-blind, placebo-controlled, three-way cross-over study, 18 healthy men received, with an interval of 24 h, two oral doses of 50 mg lumiracoxib or for comparison, 90 mg etoricoxib, for which local tissue accumulation has not been claimed as therapeutic component. Systemic and local drug concentrations, assessed by means of subcutaneous in-vivo microdialysis, were related to COX-2 inhibiting effects, quantified as inhibition of prostaglandin ex-vivo production in whole blood as well as local tissue prostaglandin (PG) concentrations. Twenty-four hours after the first dose, only etoricoxib was detectable in plasma and inhibited PGE2 production. In contrast, after the second dose, systemic PGE2 concentrations were significantly reduced by both coxibs, indicating similar maximum systemic effects of the selected doses. The local COX-2 inhibition by etoricoxib was most pronounced for PGD2. To the contrary, no indication was given of local inhibition of PG production by lumiracoxib at the dose tested. Doses of 50 mg lumiracoxib and 90 mg etoricoxib produced similar maximum inhibition of systemic COX-2 function whereas 50 mg lumiracoxib was ineffective in producing local COX-2 inhibition. At a 50 mg dosage, lumiracoxib does not provide peripheral effects that outlast its systemic actions in therapies of rheumatic diseases such as osteoarthritis.

Inhibition of the early asthmatic response to inhaled allergen by the 5-lipoxygenase activating protein inhibitor GSK2190915: a dose–response study

BackgroundGSK2190915, a 5-lipoxygenase activating protein inhibitor, inhibits the production of cysteinyl leukotrienes and leukotriene B4 and 5-oxo-6,8,11,14-eicosatetraenoic acid. We have previously reported that GSK2190915 100 mg daily inhibits early and late asthmatic responses to inhaled allergen; the effects of lower doses have not been reported. This study assessed the dose–response effects of GSK2190915 10 mg and 50 mg on the early asthmatic response (EAR) to inhaled allergen.MethodsNineteen subjects with mild asthma and an EAR were enrolled in a randomized, double-blind, three-way crossover study of GSK2190915 10 mg, 50 mg, and placebo orally once-daily for 3 days. Allergen challenge was performed 2 hours after the third dose.ResultsCompared with placebo, GSK2190915 10 mg and 50 mg caused significant, dose-dependent attenuation of the minimum forced expiratory volume at 1 second (FEV1) absolute change from baseline; mean treatment differences were 0.21 L (95% confidence interval [CI] 0.04 L, 0.38 L) and 0.41 L (95% CI 0.24 L, 0.58 L), respectively. GSK2190915 50 mg was more effective than 10 mg; mean difference between treatments was 0.20 L, (95% CI 0.03 L, 0.36 L). Compared with placebo, GSK2190915 50 mg, but not 10 mg, significantly inhibited the weighted mean FEV1 absolute change from baseline.ConclusionGSK2190915 50 mg attenuated the EAR similarly to GSK2190915 100 mg in our previous study, suggesting 50 mg is at the top of the dose–response curve. GSK2190915 10 mg is a suboptimal dose. The EAR can be used to assess the therapeutic dose of a new treatment for asthma.

Ethylphenidate: From biomarker to designer drug

The following is a brief background and account of the psychostimulant "designer drug" and curious methylphenidate-ethanol transesterification metabolite, ethylphenidate (EPH; Fig 1). That is ethylphenidate with an "E", not it's well known homolog, methylphenidate (MPH; Ritalin, Concerta, others) – the first-line agent for the treatment of attention-deficit/hyperactivity disorder (ADHD). Note that the only structural difference resides in the ester where EPH has an ethyl group rather than the methyl group in MPH.

The efficacy of once-daily fluticasone furoate/vilanterol in asthma is comparable with morning or evening dosing

To investigate the effect of time of day of dosing (morning or evening) on lung function following administration of fluticasone furoate (FF)/vilanterol (VI) 100/25 mcg. Double-blind, placebo-controlled, randomised, three-way crossover study. Subjects with persistent asthma (N = 26) received FF/VI (morning or evening) or matching placebo once-daily for 14 (± 2 days) via dry powder inhaler (DPI). Weighted mean (0-24h) and pre-treatment FEV1 (morning and evening) were determined after the Day 14 evening dose, together with mean pre-treatment (morning and evening) peak expiratory flow (PEF) on Days 2-12. FF/VI 100/25 administered morning or evening produced clinically significant increases in weighted mean FEV1: the differences [95% confidence interval (CI)] from placebo were 377 mL [293, 462] and 422 mL [337, 507], respectively; the difference between morning and evening dosing was -44 mL [-125, 36]. Day 14 pre-treatment morning FEV1 differences [95% CI] from placebo were 403 mL [272, 533] and 496 mL [369, 624] after morning and evening dosing, respectively; the morning:evening treatment difference was -94 mL [-221, 34]. Pre-treatment evening FEV1 differences [95% CI] from placebo were 275 mL [169, 380] and 309 mL [205, 413] after morning and evening dosing, respectively; the morning:evening treatment difference was -34 mL [-138, 70]. FF/VI (morning or evening) produced rapid increases in PEF with the full effect apparent after the first dose and maintained throughout the 14-day treatment period. FF/VI 100/25 produces comparable improvements in lung function whether dosed in the morning or evening in subjects with persistent asthma.

Postprandial effects of two Chinese liquors on selected cardiovascular disease risk factors in young men

The aim of this study was to investigate postprandial effects of two Chinese liquors on s elected cardiovascular disease risk factors in humans. Sixteen healthy men were randomized into three groups in a three-way crossover study: tea-flavor liquor (TFL), traditional Chinese liquor (TCL) and water control (WC). Every subject consumed 60 mL of either liquor (45% (v/v) ethanol) or water together with a high-fat meal, respectively. Compared with baseline, serum uric acid was significantly increased in TFL group (0.5-hour: P = 0.012; 1-hour: P = 0.001; 2-hour: P = 0.008) and it was significantly decreased in WC group (1-hour: P = 0.001; 2-hour: P = 0.001; 4-hour: P < 0.001), while uric acid was non-significantly increased in the TCL group. High-sensitive C-reactive protein (hs-CRP) was significantly increased in the TCL (P = 0.014) and WC (P = 0.008) groups at postprandial 4 hours compared with baseline. There was no significant difference between groups during the postprandial period for these two parameters or other biochemical parameters. In conclusion, both liquors increased postprandial uric acid, and no significant difference was observed for the effects of TFL and TCL on the measured biochemical parameters.

Single‐Dose and Multiple‐Dose Pharmacokinetics and Dose Proportionality of Intravenous and Intramuscular HPβCD‐Diclofenac (Dyloject) Compared with Other Diclofenac Formulations

To evaluate single- and repeated-dose pharmacokinetics (PK) and dose proportionality of hydroxypropyl-β-cyclodextrin (HPβCD)-diclofenac compared with Voltarol after intravenous (IV) and intramuscular (IM) administration. Study 1: Single-dose randomized four-way crossover study. Study 2: Multiple-dose randomized three-way crossover study. Clinical research center. Healthy adult volunteers. Study 1: Subjects received HPβCD-diclofenac and Voltarol, IV and IM, with a 5-day washout between treatment periods. Study 2: Subjects received two doses of IV HPβCD-diclofenac and oral Cataflam once every 6hours for four doses with a 48-hour washout period between treatment periods. Study 1: IV HPβCD-diclofenac had a higher peak plasma concentration (Cmax ) and earlier time to reach maximum plasma concentration (Tmax ), but equivalent plasma exposure (area under the curve from time zero to t [AUC0-t ]) to IV Voltarol. The geometric mean ratio of HPβCD-diclofenac (IV) to Voltarol (IV) for AUC0-t was 106.27%. The geometric mean ratio of HPβCD-diclofenac (IM) to Voltarol (IM) for AUC0-t was 110.91%. The geometric mean ratio of HPβCD-diclofenac (IV) to HPβCD-diclofenac (IM) for AUC0-t was 101.25%. The geometric mean ratio of HPβCD-diclofenac (IM) to Voltarol (IV) for AUC0-t was 104.96%. Study 2: Cmax for diclofenac was 2904 and 6031ng/ml after the first IV dose of 18.75 and 37.5mg HPβCD-diclofenac, respectively, and was 3090 and 5617ng/ml after the fourth dose, indicating no accumulation. Plasma exposures to 18.75mg (866ng·hour/ml) and 37.5mg (1843ng·hour/ml) IV HPβCD-diclofenac bracketed that of oral Cataflam 50mg (1473ng·hour/ml). Study 1: Bioavailability in terms of AUC after IV administration was equivalent for HPβCD-diclofenac compared with Voltarol and after IM administration of HPβCD-diclofenac and Voltarol. Bioavailability in terms of AUC after IM administration of HPβCD-diclofenac was equivalent to IV administration of HPβCD-diclofenac and IV administration of Voltarol. Study 2: HPβCD-diclofenac showed dose proportionality after single- and multiple-dose administration and no accumulation of HPβCD-diclofenac. HPβCD-diclofenac was safe and well tolerated following IV and IM administration.

Investigation of Pharmacodynamic and Pharmacokinetic Interactions Between Rivaroxaban and Enoxaparin in Healthy Male Subjects.

Rivaroxaban, an oral, direct factor Xa inhibitor, is currently used in clinical practice for the prevention and treatment of thromboembolic disorders. This single-center, three-way crossover study was designed to investigate the pharmacodynamic effects of rivaroxaban (10 mg) and enoxaparin (40 mg) alone and in combination as well as the influence of enoxaparin on the pharmacokinetics of rivaroxaban in healthy male subjects. When given alone, both drugs exhibited similar, rapid anti-factor Xa activity. Combined administration resulted in an increase of ∼50% in anti-factor Xa activity and a lesser increase in activated partial thromboplastin time, compared with either drug alone. Enoxaparin had no additional effect on prolongation of the prothrombin time induced by rivaroxaban and did not affect the pharmacokinetic parameters of rivaroxaban. The results showed that rivaroxaban (10 mg) and enoxaparin (40 mg) had a similar and rapid onset of action, as indicated by the similar anti-factor Xa activity-time curves, suggesting that both drugs have a similar duration of pharmacological activity at the factor X site. Co-administration of rivaroxaban and enoxaparin is associated with enhanced pharmacodynamic effects.

High protein intake stimulates postprandial GLP1 and PYY release

Meals high in protein induce greater intermeal satiety than meals high in fat and carbohydrates. We studied the gut hormone response and subsequent food intake after breakfasts high in protein, carbohydrate or high in fat controlled for volume, calories and appearance. Eight healthy volunteers participated in this randomized three-way crossover study. Study breakfasts were calculated to provide 20% of daily energy requirements and provided either 60% of energy from protein, fat or carbohydrate. Blood was drawn half-hourly for 4 h; energy intake at a subsequent ad libitum meal was measured. Total ghrelin decreased after food intake equally with the three breakfasts. PYY levels were highest after the high protein breakfast (P = 0.005). Indeed, PYY at 240 min was highest after the high protein breakfast compared to the high fat breakfast and to the high carbohydrate breakfast (P = 0.011 and P = 0.012, respectively). GLP-1 levels were highest after the high protein breakfast (P = 0.041) at 120 min and remained higher throughout the study. These differences in gut hormones did not translate into differences in food intake (1023 ± 390 kcal after high protein, 1016 ± 388 kcal after high fat and 1158 ± 433 kcal after high carbohydrate). We conclude that a high protein meal increases circulating concentrations of the gut hormones PYY and GLP-1, but when meals are matched for volume, appearance and caloric value, these gut hormone changes do not translate into a reduction in ad libitum food intake.

The impact of allergic rhinitis and its treatment on the pharmacokinetics of nasally administered fentanyl

Fentanyl pectin nasal spray (FPNS, Lazanda® in the US and PecFent® in Europe and Australia) is a novel analgesic approved for the management of breakthrough pain in cancer patients. Given that the fentanyl is nasally administered, it is important to understand whether concomitant allergic rhinitis, or its treatment with a vasoconstrictor, would affect its absorption and, potentially, its efficacy or safety. Subjects with a history of allergic rhinitis were screened to identify subjects who developed at least moderate rhinitis symptoms on exposure to pollen allergen (either ragweed or tree) in an environmental exposure chamber (EEC). These were entered into a randomized, three-way crossover study in which each subject received 100 μg of FPNS under three exposure conditions; Control (no rhinitis), Rhinitis (symptomatic without decongestant), Treated (symptomatic with concomitant oxymetazoline). Blood samples for fentanyl were collected over a 24-hour period. A total of 132 subjects was screened to identify 54 for inclusion in the study; 31 were evaluable for pharmacokinetics. Measures of fentanyl absorption (mean or median) were similar between Control and Rhinitis conditions: Cmax 453.0 vs. 467.8 pg/ml; AUCt 1,292.3 vs. 1,325.4 pg×h/ml, AUC0-∞ 1,430.6 vs. 1,387 pg×h/ml and tmax 20 vs. 17 minutes. When oxymetazoline was co-administered, overall fentanyl absorption was slightly reduced (AUC0-∞ 1,362.4 pg×h/ml); but, more clinically relevant were the delayed rate of absorption (tmax 53 minutes) and reduced Cmax (235.3 pg/ml). Patients treated with FPNS will be unaffected by the development of allergic rhinitis; but, if oxymetazoline is prescribed, the patient would benefit from added supervision when oxymetazoline is started and stopped.

A pilot study assessing the bioavailability and pharmacokinetics of diazepam after intranasal and intravenous administration in healthy volunteers

Diazepam rectal gel (Diastat(®)) is the only FDA-approved product indicated for acute repetitive seizures. Despite its proven efficacy, most older children and adults object to this route of administration. As a result, many patients do not realize the benefit of a therapy that can improve outcomes and decrease healthcare costs. Intranasal administration of benzodiazepines offers a potential alternative. The primary objective of this study was to compare the bioavailability and pharmacokinetics of two novel intranasal (IN) diazepam (DZP) formulations versus intravenous (IV) administration in healthy volunteers. Twenty-four healthy volunteers were randomized into an open-label, three-way crossover study. 10mg doses of two investigational intranasal DZP formulations (solution, suspension) and a 5mg IV dose of commercially available DZP injectable, USP were given. A two-week washout period separated treatments. Plasma samples for DZP analysis were collected pre-dose and at regular intervals up to 240 h post-dose. DZP concentration-time data were analyzed using a non-compartmental pharmacokinetics approach. Exposure following administration of DZP IN solution (absolute bioavailability - 97%) was greater than the IN suspension (absolute bioavailability - 67%). Mean Cmaxvalues for the suspension and solution formulations were 221 ng/mL and 272 ng/mL, respectively. Median time to maximum concentration (Tmax) was 1h and 1.5h for suspension and solution formulation, respectively. Both investigational intranasal formulations were well tolerated. The results of this pilot study indicate that development of an intranasal diazepam formulation with high bioavailability, reasonable variability, and good tolerability is feasible.

Safety, tolerability and pharmacokinetics of orally inhaled zanamivir: a randomised study comparing Rotacap/Rotahaler and Rotadisk/Diskhaler in healthy adults

During a pandemic, the need for available anti-influenza medications increases. There has been extensive use of the approved zanamivir Rotadisk/Diskhaler but no clinical data are available for administration by an alternative Rotacap/Rotahaler presentation. In this randomized three-way crossover study, each healthy adult received zanamivir 10 mg every 12 h for 5 days via Rotadisk/Diskhaler, via Rotacap/Rotahaler and placebo via Rotacap/Rotahaler, with a washout period between treatments. Safety assessments were conducted throughout the study and at follow-up. Serial blood samples for pharmacokinetic analysis were collected over a 12-h dose interval on day 5 of each treatment period. Pharmacokinetic parameters were compared using a mixed-effects model. A total of 18 healthy adults were recruited and 17 subjects completed the study. A total of 20 adverse events (AEs) were reported (all grade 1) by nine subjects, with no AE reported ≥1× in any treatment group. Nasal congestion, reported by one subject in the zanamivir Rotadisk/Diskhaler group, was the only drug-related AE. No serious AEs or withdrawals due to AEs occurred during the study. There were no significant changes in clinical laboratory values, vital signs or spirometry. Serum zanamivir exposures were similar after administration via Rotacap/Rotahaler and Rotadisk/Diskhaler. Both oral inhalation presentations are likely to deliver similar zanamivir concentrations to sites of influenza infection in the respiratory tract. The safety and pharmacokinetic results from this study support the use of the Rotacap/Rotahaler presentation, potentially allowing an increased number of zanamivir treatment courses to be supplied in the event of an influenza pandemic.

Endothelin-A Receptor Antagonism Modifies Cardiovascular Risk Factors in CKD

Arterial stiffness and impaired nitric oxide (NO) bioavailability contribute to the high risk for cardiovascular disease in CKD. Both asymmetric dimethylarginine (ADMA), an endogenous inhibitor of NO production, and endothelin-1 (ET-1) oppose the actions of NO, suggesting that ET-1 receptor antagonists may have a role in cardiovascular protection in CKD. We conducted a randomized, double-blind, three-way crossover study in 27 patients with proteinuric CKD to compare the effects of the ET(A) receptor antagonist sitaxentan, nifedipine, and placebo on proteinuria, BP, arterial stiffness, and various cardiovascular biomarkers. After 6 weeks of treatment, placebo and nifedipine did not affect plasma urate, ADMA, or urine ET-1/creatinine, which reflects renal ET-1 production; in contrast, sitaxentan led to statistically significant reductions in all three of these biomarkers. No treatment affected plasma ET-1. Reductions in proteinuria and BP after sitaxentan treatment was associated with increases in urine ET-1/creatinine, whereas reduction in pulse-wave velocity, a measure of arterial stiffness, was associated with a decrease in ADMA. Taken together, these data suggest that ET(A) receptor antagonism may modify risk factors for cardiovascular disease in CKD.