A comparative study was done in women and men of the effects of delta 9-tetrahydrocannabinol (delta 9-THC), intravenously or orally, on dynamic activity, metabolism, excretion, and kinetics. In general no differences between the two sexes were observed. delta 9-THC is converted by microsomal hydroxylation to 11-hydroxy-delta 9-THC (11-OH-delta 9-THC), which is both a key intermediate for further metabolism to 11-nor-delta 9-THC-9-carboxylic acid (11-nor-acid) by liver alcohol-dehydrogenase enzymes and a potent psychoactive metabolite. Major differences in the ratio of the concentration of 11-OH-delta 9-THC to that of delta 9-THC in plasma were found after intravenous dosing (ratio 1:10 to 20) compared with oral administration (ratio 0.5 to 1:1). The final metabolic products are the 11-nor-acids and the related, more polar acids. Urinary excretion of delta 9-THC is restricted to acidic nonconjugated and conjugated metabolites. After 72 hr mean cumulative urinary excretion, noted for both routes and for both sexes, ranged from 13% to 17% of the total dose. After 72 hr the cumulative fecal excretion for both sexes after intravenous administration ranged from 25% to 30%; after oral administration the range was 48% to 53%. Metabolites were found in the feces in large concentration in the nonconjugated form; concentrations of 11-OH-delta 9-THC were particularly noteworthy. Kinetics of delta 9-THC and metabolites were much the same for female and male subjects. For delta 9-THC, terminal-phase t1/2s for both sexes, irrespective of the route, ranged from 25 to 36 hr. A comparison of the results for AUC/dose (delta 9-THC) after oral dosing with comparable data from intravenous administration indicated bioavailability of the order of 10% to 20% for both sexes. After intravenous delta 9-THC, large apparent volumes of distribution were noted (about 10 l/kg for both sexes).
Opioids provide powerful analgesia but also efficacy-limiting adverse effects, including severe nausea, vomiting, and respiratory depression, by activating μ-opioid receptors. Preclinical models suggest that differential activation of signaling pathways downstream of these receptors dissociates analgesia from adverse effects; however, this has not yet translated to a treatment with an improved therapeutic index. Thirty healthy men received single intravenous injections of the biased ligand TRV130 (1.5, 3, or 4.5mg), placebo, or morphine (10mg) in a randomized, double-blind, crossover study. Primary objectives were to measure safety and tolerability (adverse events, vital signs, electrocardiography, clinical laboratory values), and analgesia (cold pain test) versus placebo. Other measures included respiratory drive (minute volume after induced hypercapnia), subjective drug effects, and pharmacokinetics. Compared to morphine, TRV130 (3, 4.5mg) elicited higher peak analgesia (105, 116 seconds latency vs 75 seconds for morphine, P<.02), with faster onset and similar duration of action. More subjects doubled latency or achieved maximum latency (180 seconds) with TRV130 (3, 4.5mg). Respiratory drive reduction was greater after morphine than any TRV130 dose (-15.9 for morphine versus -7.3, -7.6, and -9.4 h*L/min, P<.05). More subjects experienced severe nausea after morphine (n=7) than TRV130 1.5 or 3mg (n=0, 1), but not 4.5mg (n=9). TRV130 was generally well tolerated, and exposure was dose proportional. Thus, in this study, TRV130 produced greater analgesia than morphine at doses with less reduction in respiratory drive and less severe nausea. This demonstrates early clinical translation of ligand bias as an important new concept in receptor-targeted pharmacotherapy.
In a dose-ranging study of amprenavir (formerly 141W94), an inhibitor of the protease enzyme of human immunodeficiency virus (HIV) type 1, single-dose and steady-state pharmacokinetic parameters were estimated from plasma samples collected on day 1 and during week 3, respectively. Amprenavir was administered on either a twice-daily (b.i.d.) or three-times-daily dosage schedule to 62 HIV-infected adults, 59 of whom had pharmacokinetic data. Log-log regression analysis (the power model) revealed that the steady-state area under the curve (AUC ss ) and the maximum, minimum, and average concentrations at steady state (C max,ss , C min,ss , and C avg,ss , respectively) increased in a dose-proportional manner over the 300-to 1,200-mg dose range. Steady-state clearance was dose independent. AUC ss /AUC 03ؕ decreased linearly with dose and correlated significantly with treatment-associated decreases in ␣ 1 -acid glycoprotein. After 3 weeks, the dose of 1,200 mg b.i.d. provided a median amprenavir C min,ss (0.280 g/ml) that was higher than the median in vitro 50% inhibitory concentration for clinical HIV isolates (0.023 g/ml), even after adjustment for protein binding. The median amprenavir C min,ss was also greater than the estimated in vivo trough concentration calculated to yield 90% of the maximum antiviral effect (0.228 g/ml) over 4 weeks. A pharmacodynamic analysis of the relationship between steady-state pharmacokinetic parameters and safety revealed headache and oral numbness to be the only side effects significantly associated with C max . The pharmacodynamic relationship defined in this study supports the use of 1,200 mg b.i.d. as the approved dose of amprenavir.
We present a semi-automated framework for constructing factoid question answering (QA) datasets, where an array of question characteristics are formalized, including structure complexity, function, commonness, answer cardinality, and paraphrasing. Instead of collecting questions and manually characterizing them, we employ a reverse procedure, first generating a kind of graph-structured logical forms from a knowledge base, and then converting them into questions. Our work is the first to generate questions with explicitly specified characteristics for QA evaluation. We construct a new QA dataset with over 5,000 logical form-question pairs, associated with answers from the knowledge base, and show that datasets constructed in this way enable finegrained analyses of QA systems. The dataset can be found in https://github.com/ ysu1989/GraphQuestions.
Adding RTV to APV resulted in clinically and statistically significant increases in APV AUC and C(min) with variable effects on maximum concentration. The two RTV doses had similar effects on APV but AEs were more frequent with 300 mg RTV.
BackgroundAripiprazole lauroxil (AL) is a long-acting injectable medication approved for the treatment of schizophrenia. Current AL regimens are 441 mg, 662 mg, and 882 mg administered monthly (every 4 weeks [q4wk]), or 882 mg administered every 6 weeks (q6wk).ObjectiveWe examined the feasibility of a 2-month (every 8 weeks [q8wk]) dosing interval of AL in a phase I open-label pharmacokinetic study investigating AL 1064 mg administered q8wk for 24 weeks, followed by 20 weeks of safety and pharmacokinetic measurements (ClinicalTrials.gov ID: NCT02320032). Second, a population pharmacokinetic model (referred to as the 2MPopPK model) was generated using data collected from the present trial, as well as data obtained from earlier studies.MethodsThe phase I study included patients with schizophrenia or schizoaffective disorder maintained on an oral antipsychotic (n = 140) who were assigned to one of three groups: AL 441 mg q4wk, AL 882 mg q6wk, or AL 1064 mg q8wk, with a total of seven, five, or four injections administered, respectively. No oral aripiprazole lead-in supplementation was administered and patients continued on maintenance oral antipsychotics. Pharmacokinetic samples were collected at various time points during the 24-week study period and the 20-week follow-up period. Plasma concentrations obtained from the phase I study were analyzed using non-compartmental methods. Additionally, the data were combined with data collected from prior studies to develop the 2MPopPK model.ResultsFollowing the final injection of AL in the phase I study, maximum aripiprazole concentrations were achieved 24.4–35.2 days after the last dose and persisted for the duration of the study. The mean C avg,ss values were 125.8 ng/ml, 131.1 ng/ml, and 140.7 ng/ml for the 441 mg q4wk, 882 mg q6wk, and 1064 mg q8wk doses, respectively. The mean elimination half-life of aripiprazole following the last dose was 53.9 days for the 1064 mg dose, 55.1 days for the 882 mg dose, and 57.2 days for the 441 mg dose. The 2MPopPK dataset included 14,524 aripiprazole concentrations from 700 patients with schizophrenia. The duration of absorption of aripiprazole was estimated as 43 days (95% confidence interval [CI] 42–45 days), which was preceded by a 3.2-day lag time (95% CI 3.0–3.5 days) for a total duration of input into the systemic circulation of 46 days following intramuscular administration of AL. Multiple-dose simulations showed that the 1064 mg q8wk regimen provides aripiprazole concentrations within the concentration range associated with 441 mg and 882 mg q4wk doses previously demonstrated to be efficacious in a phase III study.ConclusionThese data from the phase I study and the 2MPopPK model support the suitability of using the AL 1064 mg dose as a 2-month (q8wk) dose interval option for the treatment of schizophrenia.Electronic supplementary materialThe online version of this article (doi:10.1007/s40263-017-0447-7) contains supplementary material, which is available to authorized users.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.