AimsTo evaluate apixaban single dose safety, tolerability, pharmacokinetics and pharmacodynamics and assess the effect of food on apixaban pharmacokinetics.MethodsA double-blind, placebo-controlled, single ascending-dose, first-in-human study assessed apixaban safety, pharmacokinetics and pharmacodynamics in healthy subjects randomized to oral apixaban (n = 43; 0.5–2.5 mg as solution or 5–50 mg as tablets) or placebo (n = 14) under fasted conditions. An open label, randomized, two treatment crossover study investigated apixaban pharmacokinetics/pharmacodynamics in healthy subjects (n = 21) administered apixaban 10 mg in fasted and fed states. Both studies measured apixaban plasma concentration, international normalized ratio (INR), activated partial thromboplastin time (aPTT) and prothrombin time (PT) or a modified PT (mPT).ResultsIn the single ascending-dose study increases in apixaban exposure appeared dose-proportional. Median tmax occurred 1.5–3.3 h following oral administration. Mean terminal half-life ranged between 3.6 and 6.8 h following administration of solution doses ≤2.5 mg and between 11.1 and 26.8 h for tablet doses ≥5 mg. Concentration-related changes in pharmacodynamic assessments were observed. After a 50 mg dose, peak aPTT, INR and mPT increased by 1.2-, 1.6- and 2.9-fold, respectively, from baseline. In the food effect study: 90% confidence intervals of geometric mean ratios of apixaban Cmax and AUC in a fed vs. fasted state were within the predefined no effect (80–125%) range. Apixaban half-life was approximately 11.5 h. The effect of apixaban on INR, PT and aPTT was comparable following fed and fasted administration.ConclusionsSingle doses of apixaban were well tolerated with a predictable pharmacokinetic/pharmacodynamic profile and a half-life of approximately 12 h. Apixaban can be administered with or without food.
Multiple oral doses of apixaban were safe and well tolerated over a 10-fold dose range, with pharmacokinetics with low variability and concentration-related increases in clotting time measures.
Fibrillation (ARISTOTLE) trial, apixaban compared with warfarin reduced stroke and systemic embolism, major bleeding, and mortality. We evaluated treatment effects in relation to 2 predictions of time in therapeutic range (TTR). Methods and Results-The trial randomized 18 201 patients with atrial fibrillation to apixaban 5 mg twice daily or warfarin for at least 12 months. For each patient, a center average TTR was estimated with the use of a linear mixed model on the basis of the real TTRs in its warfarin-treated patients, with a fixed effect for country and random effect for center. For each patient, an individual TTR was also predicted with the use of a linear mixed effects model including patient characteristics as well. Median center average TTR was 66% (interquartile limits, 61% and 71%). Rates of stroke or systemic embolism, major bleeding, and mortality were consistently lower with apixaban than with warfarin across center average TTR and individual TTR quartiles. In the lowest and highest center average TTR quartiles, hazard ratios for stroke or systemic embolism were 0.73 (95% confidence interval [CI], 0.53-1.00) and 0.88 (95% CI, 0.57-1.35) (P interaction =0.078), for mortality were 0.91 (95% CI, 0.74-1.13) and 0.91 (95% CI, 0.71-1.16) (P interaction =0.34), and for major bleeding were 0.50 (95% CI, 0.36-0.70) and 0.75 (95% CI, 0.58-0.97) (P interaction =0.095), respectively. Similar results were seen for quartiles of individual TTR.© 2013 American Heart Association, Inc.Circulation is available at http://circ.ahajournals.org DOI: 10.1161/CIRCULATIONAHA.112.142158Continuing medical education (CME) credit is available for this article. Go to http://cme.ahajournals.org to take the quiz. W arfarin and other vitamin K antagonists effectively prevent stroke in patients with atrial fibrillation (AF), but they have a narrow therapeutic window with an increased risk of stroke and bleeding when above or below the therapeutic range of the international normalized ratio (INR) of 2.0 to 3.0.1-3 The dose response is influenced by several factors such as age, body weight, genetic variation, food, and comedications. Regular INR-guided dose adjustments are therefore necessary.1-3 However, there are large variations of the time in therapeutic range (TTR) across individuals, sites, and countries, and these variations are related to patient outcomes. [4][5][6][7][8][9] Several trials have shown recently that the quality of warfarin use, as measured with INR control at the center or country level, may interact with the treatment effects of new antithrombotic treatments when compared with warfarin. 10-12 Editorial see p 2163 Clinical Perspective on p 2176Apixaban is a new oral direct factor Xa inhibitor providing stable anticoagulation at a fixed dose twice daily without the need for anticoagulation monitoring. In the prospective, randomized, and double-blind Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation (ARISTOTLE) trial including 18 201 patients with AF and at least 1 additiona...
This study was conducted to investigate the extent of absorption in different regions of the gastrointestinal (GI) tract. The relative bioavailability of an apixaban crushed tablet was also assessed to investigate the effect of dissolution on absorption. This was an open-label, randomized, 4-period, 4-treatment crossover study with a 7-day washout period balanced for first-order residual effects in 12 healthy subjects. Subjects received a single dose of a 2.5-mg apixaban solution administered orally, released in the distal small intestine and in the ascending colon. In addition, subjects received a single dose of a 2.5-mg apixaban crushed tablet released in the ascending colon. The solution and crushed tablet were delivered via Enterion capsules. The location of Enterion capsules was monitored using scintigraphic imaging. Apixaban maximum observed plasma concentration (C ) and area under the plasma concentration-time curve from zero to the time of the last quantifiable concentration (AUC ) decreased by approximately 60% when it was delivered to the distal small bowel compared with the oral administration. A greater decrease was observed when it was delivered to the ascending colon, with reductions of 90% and 84% in C and AUC , respectively. A crushed tablet delivered to the ascending colon resulted in exposure that was approximately 40% of that observed for solution released in the same region. These findings indicate that apixaban exhibits region-dependent absorption and that dissolution/solubility of the solid-dose form is limited in the ascending colon. Apixaban absorption decreased progressively along the GI tract, indicating that absorption occurs primarily in the upper GI tract.
A 1992 telephone survey of households in seven mid-South states provided data for comparing the opinions of NIPF owners with those of the general public. Topics explored included traditional forest management practices, governmental regulation of tree cutting to protect environmental values, and trade-offs between environmental protection, private property rights, and economic development. In each of these areas the views of NIPF owners were found not to differ significantly from those of the general public. A widespread desire for environmental protection tempers views toward forest practices, forest-based economic development, and private property rights. The relationships between NIPF owners' demographic characteristics, ownership activities, and opinions were explored. Study results challenged common assumptions about NIPF owners, questioned the effectiveness of existing forestry education efforts, and argue for a stronger, more explicitly environmental orientation in all forestry activities. South. J. Appl. For. 21(1):37-43.
Sal (Shorea robusta) forests, a dominant forest type in Nepal, experience different disturbance intensities depending on management regimes. This study compares the impact of disturbance on Nepalese Sal forests, which are managed on three major management regimes: protected area, state-managed forest, and buffer zone community forest. Using a systematic sampling approach, we sampled 20 plots, each covering 500 square meters, and nested plots within each main plot to measure pole and regeneration for each management regime. We recorded forest characteristics including tree species, counts, diameter, height, crown cover, and disturbance indicators. We compared forest attributes such as diversity indices, species richness, and stand structure by management regime using analysis of variance and regression analysis. The forest management regimes were classified into three disturbance levels based on disturbance factor bundles, and the buffer zone community forest was found to have the highest disturbance while the protected forest had the lowest disturbance. Species richness, diversity, evenness, abundance, density and basal area were higher, but regeneration was lower in protected area and state-managed forest compared to the buffer zone community forests. This suggests positive impacts of moderate disturbance on regeneration. The management plan should prioritize the minimization of excessive disturbance to balance forest conservation and provide forest resources to local users.
Jatropha seed cake (JSC) is an excellent source of protein but does contain some antinutritional factors (ANF) that can act as toxins and thus negatively affect the growth and health status of fish. While this can limit the use of JSC, detoxified Jatropha protein isolate (DJPI) may be a better option. An 8-week study was performed to evaluate dietary DJPI to common carp Cyprinus carpio. Five iso-nitrogenous diets (crude protein of 38%) were formulated that consisted of a C (fish meal (FM) based protein), J or J (50 and 75% of FM protein replaced by DJPI), and S or S (50 and 75% of FM protein replaced by soy protein isolate, SPI) and fed to triplicate groups of 75 carp fingerlings (75; av. wt. ± SD; 11.4 ± 0.25 g). The growth, feeding efficiencies, digestibility, plasma biochemistry, and intestinal enzymes were measured. Results showed that growth performance of fish fed the S- or DJPI-based diets were not significantly different from those fed the C diet, while carp fed the S had significantly better growth than the J diet. Fish fed the J diet had significantly lower protein and lipid digestibility as well as significantly lower intestinal amylase and protease activities than all other groups. However, all plant protein-based diets led to significantly higher crude protein, crude lipid, and gross energy in the body of common carp compared to the control treatment. Plasma cholesterol and creatinine significantly decreased in the plant protein fed groups, although plasma triglyceride as well as the red blood cells count, hematocrit, albumin, globulin, total plasma protein, and lysozyme activity were higher in plant protein fed groups compared to FM fed group. White blood cells, hemoglobulin concentration, alkaline phosphatase and alanine transaminase activities, and glucose level in blood did not differ significantly among treatments. The results suggest that the DJPI is non-toxic to carp and can be used to replace FM in the diets of common carp up to 75%, but further research to potentially reduce some inherent ANF within this protein source, such as non-starch polysaccharides, may improve nutrient utilization.
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