Exploring In Silico Prediction of the Unbound Brain-to-Plasma Drug Concentration Ratio: Model Validation, Renewal, and Interpretation

2015 ◽  
Vol 104 (3) ◽  
pp. 1197-1206 ◽  
Author(s):  
Srinidhi Varadharajan ◽  
Susanne Winiwarter ◽  
Lars Carlsson ◽  
Ola Engkvist ◽  
Ajay Anantha ◽  
...  
Keyword(s):  
Model Validation ◽  
Drug Concentration ◽  
In Silico ◽  
Concentration Ratio ◽  
Plasma Drug Concentration ◽  
Ratio Model ◽  
In Silico Prediction ◽  
Plasma Drug

Prediction of human blood-to-plasma drug concentration ratio

2010 ◽  
pp. n/a-n/a ◽  
Author(s):  
Takahide Uchimura ◽  
Motohiro Kato ◽  
Tomohisa Saito ◽  
Haruki Kinoshita
Keyword(s):  
Human Blood ◽  
Drug Concentration ◽  
Concentration Ratio ◽  
Plasma Drug Concentration ◽  
Plasma Drug

scholarly journals Preparation and Pharmacokinetic Study of Daidzein Long-Circulating Liposomes

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Qiao Wang ◽  
Wenjin Liu ◽  
Junjun Wang ◽  
Hong Liu ◽  
Yong Chen
Keyword(s):  
Single Dose ◽  
Drug Concentration ◽  
Drug Loading ◽  
Plasma Drug Concentration ◽  
The Body ◽  
Molar Ratio ◽  
Terminal Phase ◽  
Plasma Drug ◽  
Ultrasonic Time ◽  
Time Required

Abstract In this study, daidzein long-circulating liposomes (DLCL) were prepared using the ultrasonication and lipid film-hydration method. The optimized preparation conditions by the orthogonal design was as follows: 55 to 40 for the molar ratio of soybean phosphatidylcholine (SPC) to cholesterol, 1 to 10 for the mass ratio of daidzein to total lipid (SPC and cholesterol) (w:w), the indicated concentration of 5% DSPE-mPEG2000 (w:w), 50 °C for the hydration temperature, and 24 min for the ultrasonic time. Under these conditions, the encapsulation efficiency and drug loading of DLCL were 85.3 ± 3.6% and 8.2 ± 1.4%, respectively. The complete release times of DLCL in the medium of pH 1.2 and pH 6.9 increased by four- and twofold of that of free drugs, respectively. After rats were orally administered, a single dose of daidzein (30 mg/kg) and DLCL (containing equal dose of daidzein), respectively, and the MRT0−t (mean residence time, which is the time required for the elimination of 63.2% of drug in the body), t1/2 (the elimination half-life, which is the time required to halve the plasma drug concentration of the terminal phase), and AUC0−t (the area under the plasma drug concentration-time curve, which represents the total absorption after a single dose and reflects the drug absorption degree) of daidzein in DLCL group, increased by 1.6-, 1.8- and 2.5-fold as compared with those in the free group daidzein. Our results indicated that DLCL could not only reduce the first-pass effect of daidzein to promote its oral absorption, but also prolong its mean resident time to achieve the slow-release effect.

scholarly journals Evaluation of the pharmacokinetic interaction and safety of ubrogepant coadministered with acetaminophen or nonsteroidal anti-inflammatory drugs: A randomized trial

2020 ◽  
Vol 3 ◽  
pp. 251581632092118 ◽  
Author(s):  
Abhijeet Jakate ◽  
Ramesh Boinpally ◽  
Matthew Butler ◽  
Kaifeng Lu ◽  
Kristi Womack ◽  
...  
Keyword(s):  
Drug Concentration ◽  
Geometric Mean ◽  
Plasma Drug Concentration ◽  
Migraine Treatment ◽  
Maximum Plasma ◽  
Plasma Drug ◽  
Two Phase ◽  
Inflammatory Drugs ◽  
Anti Inflammatory ◽  
Healthy Participants

Background: Ubrogepant is a novel, oral calcitonin gene–related peptide receptor antagonist approved by the US Food and Drug Administration for acute treatment of migraine with or without aura in adults. Objectives: To assess potential pharmacokinetic (PK) drug–drug interactions in healthy participants and inform the safety and tolerability of ubrogepant alone and in combination with acetaminophen or nonsteroidal anti-inflammatory drugs (NSAIDs) in healthy participants and participants with migraine. Methods: Two phase 1, three-way crossover studies randomized healthy adults to 100 mg ubrogepant alone, 1000 mg acetaminophen or 500 mg naproxen alone, and 100 mg ubrogepant plus 1000 mg acetaminophen or 500 mg naproxen. Geometric mean ratios (GMRs) and 90% confidence intervals were calculated based on statistical comparison of maximum plasma drug concentration ( C max) and area under the plasma drug concentration–time curve (AUC) for treatment in combination versus alone. Two phase 3 randomized trials included adults with migraine. Treatment-emergent adverse events (TEAEs) were evaluated. Results: Time to C max and terminal elimination half-life for all treatments were unchanged when coadministered. Ubrogepant C max and AUC increased by approximately 40% when coadministered with acetaminophen. Acetaminophen C max decreased by 24% (GMR = 0.76) when coadministered with ubrogepant. There were no significant PK interactions between ubrogepant and naproxen. TEAE rates in the acetaminophen and NSAID rescue medication groups were similar to ubrogepant alone. Conclusions: Coadministration of ubrogepant and acetaminophen resulted in a statistically significant increase in ubrogepant exposure and a decrease in acetaminophen C max; however, these changes were not clinically relevant. No statistically or clinically relevant changes in PK were associated with ubrogepant and naproxen coadministration. No safety concerns were identified for ubrogepant alone or in combination with acetaminophen or NSAIDs.

Impact of Apixaban On a Large Panel of Routine or More Specific Coagulation Assays.

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2275-2275
Author(s):  
Jonathan Douxfils ◽  
François Mullier ◽  
Christian Chatelain ◽  
Bernard Chatelain ◽  
Dogné Jean-Michel
Keyword(s):  
Atrial Fibrillation ◽  
Drug Concentration ◽  
Partial Thromboplastin Time ◽  
Factor Xa ◽  
Activated Partial Thromboplastin Time ◽  
Plasma Drug Concentration ◽  
Thrombin Time ◽  
Plasma Drug ◽  
Clotting Time

Abstract Abstract 2275 Introduction: Apixaban is direct factor-Xa inhibitor that reached the market for the prevention of venous thromboembolism in patients undergoing major orthopaedic surgery. It is also being evaluated in the reduction of recurrent ischemic events when added to antiplatelet therapy after an acute coronary syndrome and in the prevention of stroke in patients with non-valvular atrial fibrillation. Thanks to its predictable pharmacokinetic profile, biological monitoring is not required. Nevertheless, evaluation of plasma drug concentration may be valuable in specific situations such as recurrent thrombosis, bleedings, before urgent surgery, in case of bridging and in case of at least two risk factors among the following ones: drug interactions with caution, moderate renal impairment and moderate hepatic impairment; Monitoring may also be useful in infants, pregnant women or in extreme body weights, although no relevant data on drug levels associated with approximate therapeutic and harmful ranges are currently available. Material and Methods: Apixaban was spiked at increasing concentrations (0, 5, 10, 20, 50, 100, 200 and 500 ng/mL) in pooled citrated normal human platelet poor plasma (PPP) to measure Prothrombin Time (PT) and dilute PT with different thromboplastin, Thrombin Generation Assay (TGA) with different inducers and activity on different anti-Xa chromogenic assays. Activated Partial Thromboplastin Time with different reagents, Thrombin Time (TT), Ecarin Clotting Time (ECT) and Reptilase Time (RT), measurement of fibrinogen (Clauss method and PT-derived method) and antithrombin (anti-IIa and anti-Xa based chromogenic assays) were also tested. We also evaluated the impact of apixaban on assays used for the determination of lupus anticoagulant such as the DRVV-T.. (Screen and Confirm) as well as the PTT-LA.. and the Staclot-LA.. . Results and Discussion: As mentioned in previous studies, PT showed a weak sensitivity towards apixaban in comparison with the plasma range obtained in short pharmacokinetic studies. Indeed, the concentration needed to double the clotting time was 154 ng/mL with the most sensitive reagent while the mean Cmax obtained in a short PK study after one oral intake of 5 mg apixaban (dose given in atrial fibrillation) was 96 ng/mL. Therefore, the sensitivity of PT is not strong enough to allow accurate quantitative measurement of the plasma drug concentration (Table 1). Activated Partial Thromboplastin Time presented a better sensitivity but showed a plateau after 100 ng/mL reflecting the uselessness of this test for the quantification of apixaban. Thrombin Time, ECT and RT were logically not affected while DRVV-T.. showed a sensitivity of 205 ng/mL (Screen), which is once again not enough sensitive. On the opposite, chromogenic anti-Xa assays seemed to be very sensitive (Figure 2 and Table 1). Nevertheless, the relation was not always linear and some methodologies needed to be adapted to ensure a broader range of application. TGA (Figure 1) may be useful to assess the pharmacodynamics effects of apixaban on the coagulation process. Nevertheless, the turn around time and the lack of standardisation are currently limitations that restrict the use of this method. In the case of the exploration of an haemorrhagic event, specific tests such as RT, fibrinogen (Clauss and PT-derived method (dFib)), TT and clotting factor activity may be used. Apixaban did not interfere with these tests. Antithrombin determination if also of importance and chromogenic anti-IIa based assays should be used in face of patients treated with apixaban to avoid misdiagnosis since an overvaluation of 12% by 100 ng/mL was shown using one chromogenic anti-Xa based assay. Conclusion: PT may not be used as screening test to assess the risk of bleedings. A more specific and sensitive assay such as chromogenic anti-Xa assays using calibrators should be used to correctly assess the concentration of apixaban. Determination of lupus anticoagulant using DRVV-T.. and PTT-LA.. or Staclot LA.. as well as the determination of antithrombin using factor-Xa based chromogenic assays, were influenced by apixaban. Finally, standardization of the time between the last intake of apixaban and the sampling is mandatory. Figures: Disclosures: No relevant conflicts of interest to declare.

NOMIFENSINE OVERDOSE AND PLASMA DRUG CONCENTRATION

The Lancet ◽  
1979 ◽  
Vol 313 (8106) ◽  
pp. 56 ◽  
Author(s):  
Sheila Dawling ◽  
Robin Braithwaite ◽  
Peter Crome
Keyword(s):  
Drug Concentration ◽  
Plasma Drug Concentration ◽  
Plasma Drug
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