The impact of missing values in the concentration-time curve on the assessment of bioequivalence

2005 ◽  
Vol 4 (2) ◽  
pp. 91-99 ◽  
Author(s):  
Allan Donner ◽  
Walter W. Hauck ◽  
Guangyong Zou
Keyword(s):  
Missing Values ◽  
Time Curve ◽  
Concentration Time ◽  
The Impact

scholarly journals Impact of efavirenz, ritonavir-boosted lopinavir and nevirapine based antiretroviral regimens on the pharmacokinetics of lumefantrine and safety of artemether-lumefantrine in falciparum-negative HIV-infected Malawian adults stabilized on antiretroviral therapy

2018 ◽  
Author(s):  
Clifford George Banda ◽  
Fraction Dzinjalamala ◽  
Mavuto Mukaka ◽  
Jane Mallewa ◽  
Victor Maiden ◽  
...  
Keyword(s):  
Safety Profile ◽  
Standard Dose ◽  
Time Curve ◽  
Therapeutic Implications ◽  
Antiretroviral Therapies ◽  
Concentration Time ◽  
Group I ◽  
Conflicting Evidence ◽  
Immunodeficiency Virus ◽  
The Impact

ABSTRACTThere is conflicting evidence of the impact of commonly used antiretroviral therapies (ARTs) on the pharmacokinetics of lumefantrine and safety profile of artemether-lumefantrine. We compared the area under the concentration-time curve (AUC0-14 days) of lumefantrine and safety profile of artemether-lumefantrine in malaria-negative human immunodeficiency virus (HIV) infected adults in two steps. In step 1, a half-dose adult course of artemether-lumefantrine was administered as a safety check in four groups (n = 6/group): (i) antiretroviral-naïve, (ii) on nevirapine-based ART, (iii) on efavirenz-based ART and (iv) on ritonavir-boosted lopinavir-based ART. In step 2, a standard-dose adult course of artemether-lumefantrine was administered to a different cohort in three groups (n = 10–15/group): (i) antiretroviral-naïve, (ii) on efavirenz-based ART and (iii) on ritonavir-boosted lopinavir-based ART. In step 1, lumefantrine’s AUC0-14 days was 53% [95% CI: 0.27-0.82] lower in the efavirenz-based ART group than the ART-naïve group and was 2.4 [95% CI: 1.58-3.62] and 2.9 [95% CI: 1.75-4.72] times higher in the nevirapine and ritonavir-boosted lopinavir groups, respectively. In step 2, lumefantrine’s AUC0-14 days was 1.9 [95% CI: 1.26-3.00] times higher in the ritonavir-boosted lopinavir group and not significantly different between the efavirenz-and ART-naïve groups (0.99 [95% CI: 0.63-1.57]). Frequent cases of haematological abnormalities (thrombocytopenia and neutropenia) were observed in the nevirapine group in step 1, leading to a recommendation from the data and safety monitoring board not to include a nevirapine group in step 2. Artemether-lumefantrine was well tolerated in the other groups. The therapeutic implications of these findings need to be evaluated among HIV-malaria co-infected adults.

scholarly journals Paradoxical Effect of Isoniazid on the Activity of Rifampin-Pyrazinamide Combination in a Mouse Model of Tuberculosis

2009 ◽  
Vol 53 (10) ◽  
pp. 4178-4184 ◽  
Author(s):  
Deepak Almeida ◽  
Eric Nuermberger ◽  
Rokeya Tasneen ◽  
Ian Rosenthal ◽  
Sandeep Tyagi ◽  
...  
Keyword(s):  
Pharmacokinetic Studies ◽  
Negative Interaction ◽  
Acetylation Phenotype ◽  
Time Curve ◽  
Concentration Time ◽  
Dependent Activity ◽  
The Individual ◽  
Aerosol Infection ◽  
The Impact ◽  
Dose Dependent

ABSTRACT To investigate the antagonism between isoniazid (INH) and rifampin (rifampicin) (RIF)-pyrazinamide (PZA) combination observed in Mycobacterium tuberculosis-infected mice, extensive pharmacokinetic studies of INH were performed and followed by experiments to assess the impact of increasing doses of INH on the antimicrobial activity of RIF-PZA combination. INH at 6.25 mg/kg of body weight produced a maximum concentration of drug in serum (C max) value of 4 μg/ml and an area under the concentration-time curve from 0 to 24 h (AUC0-24) value of 4.9 μg·h/ml, the former being close to the C max value observed after the standard 5-mg/kg dose in humans. INH at 25 mg/kg produced a C max value of 22 μg/ml and an AUC0-24 value of 29 μg·h/ml, the latter being close to the AUC observed after a 5-mg/kg dose of INH in humans with the slow acetylation phenotype. Beginning 2 weeks after aerosol infection with M. tuberculosis, mice were treated for 8 weeks with INH at twofold-increasing doses, ranging from 1.56 to 50 mg/kg, either alone or in combination with RIF-PZA. Given alone, INH exhibited dose-dependent activity. Combined with RIF-PZA, INH exhibited dose-dependent antagonism of RIF-PZA activity. To determine the individual components of RIF-PZA combination with which INH was antagonistic, mice were treated for 8 weeks with RIF alone, PZA alone, RIF-PZA, and INH at 3.125, 12.5, or 50 mg/kg either alone or combined with RIF or PZA. Addition of INH to RIF had additive activity, whereas addition of INH to PZA resulted in a negative interaction. Finally, a 10-mg/kg dose of INH in mice may best represent the 5-mg/kg dose in humans and decrease the antagonism of INH with RIF-PZA.

scholarly journals A Quasi-Experiment To Study the Impact of Vancomycin Area under the Concentration-Time Curve-Guided Dosing on Vancomycin-Associated Nephrotoxicity

2017 ◽  
Vol 61 (12) ◽  
Author(s):  
Natalie A. Finch ◽  
Evan J. Zasowski ◽  
Kyle P. Murray ◽  
Ryan P. Mynatt ◽  
Jing J. Zhao ◽  
...  
Keyword(s):  
Trough Concentration ◽  
Proportional Hazards ◽  
Cox Proportional Hazards ◽  
Time Curve ◽  
Cox Proportional Hazards Regression ◽  
Proportional Hazards Regression ◽  
Concentration Time ◽  
Trough Concentrations ◽  
The Impact ◽  
Quasi Experiment

ABSTRACT Evidence suggests that maintenance of vancomycin trough concentrations at between 15 and 20 mg/liter, as currently recommended, is frequently unnecessary to achieve the daily area under the concentration-time curve (AUC24) target of ≥400 mg · h/liter. Many patients with trough concentrations in this range have AUC24 values in excess of the therapeutic threshold and within the exposure range associated with nephrotoxicity. On the basis of this, the Detroit Medical Center switched from trough concentration-guided dosing to AUC-guided dosing to minimize potentially unnecessary vancomycin exposure. The primary objective of this analysis was to assess the impact of this intervention on vancomycin-associated nephrotoxicity in a single-center, retrospective quasi-experiment of hospitalized adult patients receiving intravenous vancomycin from 2014 to 2015. The primary analysis compared the incidence of nephrotoxicity between patients monitored by assessment of the AUC24 and those monitored by assessment of the trough concentration. Multivariable logistic and Cox proportional hazards regression examined the independent association between the monitoring strategy and nephrotoxicity. Secondary analysis compared vancomycin exposures (total daily dose, AUC, and trough concentrations) between monitoring strategies. Overall, 1,280 patients were included in the analysis. After adjusting for severity of illness, comorbidity, duration of vancomycin therapy, and concomitant receipt of nephrotoxins, AUC-guided dosing was independently associated with lower nephrotoxicity by both logistic regression (odds ratio, 0.52; 95% confidence interval [CI], 0.34 to 0.80; P = 0.003) and Cox proportional hazards regression (hazard ratio, 0.53; 95% CI, 0.35 to 0.78; P = 0.002). AUC-guided dosing was associated with lower total daily vancomycin doses, AUC values, and trough concentrations. Vancomycin AUC-guided dosing was associated with reduced nephrotoxicity, which appeared to be a result of reduced vancomycin exposure.

Clinical relevance of rifampicin-moxifloxacin interaction in isoniazid resistant/intolerant tuberculosis patients.

2021 ◽  
Author(s):  
Vanessa B Vogensen ◽  
Mathieu S Bolhuis ◽  
Marieke G. G. Sturkenboom ◽  
Tjip S van der Werf ◽  
Wiel C. M. de Lange ◽  
...  
Keyword(s):  
Drug Interaction ◽  
Isoniazid Resistance ◽  
Time Curve ◽  
Geometric Means ◽  
Tuberculosis Patients ◽  
Concentration Time ◽  
Drug Drug Interaction ◽  
Clinically Significant ◽  
The Impact ◽  
Higher Doses

Moxifloxacin is an attractive drug for the treatment of isoniazid-resistant rifampicin-susceptible tuberculosis (TB) or drug-susceptible TB complicated by isoniazid intolerance. However, co-administration with rifampicin decreases moxifloxacin exposure. It remains unclear whether this drug-drug interaction has clinical implications. This retrospective study in a Dutch TB centre investigated how rifampicin affected moxifloxacin exposure in patients with isoniazid-resistant or –intolerant TB. Moxifloxacin exposures were measured between 2015 and 2020 in 31 patients with isoniazid-resistant or –intolerant TB receiving rifampicin, and 20 TB patients receiving moxifloxacin without rifampicin. Moxifloxacin exposure, i.e. area under the concentration-time curve (AUC 0-24h ), and attainment of AUC 0-24h /minimal inhibitory concentration (MIC) > 100 were investigated for 400 mg moxifloxacin and 600 mg rifampicin, and increased doses of moxifloxacin (600 mg) or rifampicin (900 mg). Moxifloxacin AUC 0–24h and peak concentration with a 400 mg dose were decreased when rifampicin was co-administered compared to moxifloxacin alone (ratio of geometric means 0.61 (90% CI (0.53, 0.70) and 0.81 (90% CI (0.70, 0.94), respectively). Among patients receiving rifampicin, 65% attained an AUC 0-24h /MIC > 100 for moxifloxacin compared to 78% of patients receiving moxifloxacin alone; this difference was not significant. Seven out of eight patients receiving an increased dose of 600 mg moxifloxacin reached the target AUC 0-24h /MIC > 100. This study showed a clinically significant 39% decrease in moxifloxacin exposure when rifampicin was co-administered. Moxifloxacin dose adjustment may compensate for this drug-drug interaction. Further exploring the impact of higher doses of these drugs in patients with isoniazid resistance or intolerance is paramount.

A Comparative Pharmacokinetic Profile of Trahydropalmatine After Oral Administration of its Monomer, Rhizoma Corydalis Alkaloid Extracts and Tong-Bi-Si-Wei-Fang to Rats

2019 ◽  
Vol 15 (4) ◽  
pp. 338-345
Author(s):  
Lijun Ni ◽  
Lu Ding ◽  
Liguo Zhang ◽  
Shaorong Luan
Keyword(s):  
Oral Administration ◽  
Panax Notoginseng ◽  
Pharmacokinetic Profile ◽  
Apparent Volume ◽  
Bone Diseases ◽  
Glycyrrhiza Uralensis ◽  
Pharmacokinetic Property ◽  
Time Curve ◽  
Concentration Time

Background: Tong-Bi-Si-Wei-Fang (TBSWF) is a candidate formula of Traditional Chinese Medicine (TCM) for treating rheumatoid bone diseases, which is composed of rhizoma corydalis alkaloids, saponins of glycyrrhiza uralensis and panax notoginseng, flavonoids of rhizoma drynariae and glycyrrhiza uralensis. </P><P> Objective: Trahydropalmatine (THP), the main active ingredient of rhizoma corydalis alkaloids, was selected to study in vivo pharmacokinetics and druggability of TBSWF. Methods: The plasma concentration-time (C-T) profiles of THP and the pharmacokinetic property parameters after oral administration of THP monomer, extract of corydalis alkaloids (ECA) and TBSWF to rats, respectively were compared by a fully-validated HPLC method. Results: Compared to the THP monomer, the THP in TBSWF is absorbed faster, resides in the plasma longer and has a similar apparent volume of distribution Vz/F (10~20 L/kg). Compared to THP monomer and THP in TBSWF, the area under the concentration-time curve AUC 0-t of THP in ECA decreases two-third; Vz/F of THP in ECA (85.02 L/kg) is significantly higher than that of THP in TBSWF(p <0.05). Unlike THP monomer and THP in ECA, double peaks are observed in the C-T profile of THP after oral administration of TBSWF. THP in TBSWF exhibits slow release to a certain degree. Conclusion: The interactions among the ingredients of TBSWF promote the adsorption and prolong the residence time of THP in vivo, and provide an explanation for the advantages of TBSWF from the point of pharmacokinetics.

scholarly journals Impact of Local Liver Irradiation Concurrent Versus Sequential with Lenvatinib on Pharmacokinetics and Biodistribution

Cancers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1598
Author(s):  
Tung-Hu Tsai ◽  
Yu-Jen Chen ◽  
Li-Ying Wang ◽  
Chen-Hsi Hsieh
Keyword(s):  
Radiation Therapy ◽  
Rat Model ◽  
Systemic Therapy ◽  
Stereotactic Body Radiation Therapy ◽  
Time Curve ◽  
Stereotactic Body Radiation ◽  
Concentration Time ◽  
Sequential Regimen ◽  
Freely Moving

Concurrent and sequential regimens involving radiotherapy (RT) and lenvatinib were designed with off-target or stereotactic body radiation therapy (SBRT) doses in a freely moving rat model to evaluate the effect of RT on the pharmacokinetics (PK) of lenvatinib. Liver RT concurrent with lenvatinib decreased the area under the concentration–time curve of lenvatinib concentration (AUClenvatinib) by 51.1% with three fractions of 2 Gy (RT2Gy×3f’x, p = 0.03), and 48.9% with RT9Gy×3f’x (p = 0.03). The AUClenvatinib increased by 148.8% (p = 0.008) with RT2Gy×3f’x, and 68.9% (p = 0.009) with RT9Gy×3f’x in the sequential regimen compared to the concurrent regimen. There were no differences in the AUClenvatinib between RT2Gy×3f’x and RT9Gy×3f’x in the concurrent or sequential regimen. Both the RT2Gy×3f’x and RT9Gy×3f’x concurrent regimens markedly decreased the biodistribution of lenvatinib in the heart, liver, lung, spleen, and kidneys, which ranged from 31% to 100% for RT2Gy×3f’x, and 11% to 100% for RT9Gy×3f’x, compared to the sham regimen. The PK and biodistribution of lenvatinib can be modulated by simultaneous off-target irradiation and SBRT doses. The timing of lenvatinib administration with respect to RT, impacted the PK and biodistribution of the drug. Additionally, off-target and SBRT doses had a similar ability to modulate the effect of systemic therapy.

Effectiveness of a vancomycin dosing protocol guided by area under the concentration-time curve to minimal inhibitory concentration (AUC/MIC) with multidisciplinary team support to improve hospital-wide adherence to a vancomycin dosing protocol: A pilot study

2021 ◽  
pp. 1-6
Author(s):  
Panipak Katawethiwong ◽  
Anucha Apisarnthanarak ◽  
Kittiya Jantarathaneewat ◽  
David J. Weber ◽  
David K. Warren ◽  
...  
Keyword(s):  
Mortality Rate ◽  
Multidisciplinary Team ◽  
Kidney Injury ◽  
University Hospital ◽  
Routine Practice ◽  
Post Intervention ◽  
Coagulase Negative Staphylococci ◽  
Time Curve ◽  
Concentration Time ◽  
Quasi Experimental

Abstract Background: Limited data are available on the implementation of an area under the concentration-time curve (AUC)–based dosing protocol with multidisciplinary team (MT) support to improve adherence with vancomycin dosing protocol. Objective: To evaluate the effectiveness of an AUC-based dosing protocol with MT support intervention with adherence to a hospital-wide vancomycin dosing protocol at Thammasat University Hospital. Method: We conducted a quasi-experimental study in patients who were prescribed intravenous vancomycin. The study was divided into 2 periods; (1) the preintervention period when the vancomycin dosing protocol was already applied in routine practice and (2) the post-intervention period when the implementation of an AUC-based dosing protocol with MT support was added to the existing vancomycin dosing protocol. The primary outcome was the rate of adherence, and the secondary outcomes included acute kidney injury events, vancomycin-related adverse events, and 30-day mortality rate. Results: In total, 240 patients were enrolled. The most common infections were skin and soft-tissue infections (24.6%) and bacteremia (24.6%). The most common pathogens were coagulase-negative staphylococci (19.6%) and Enterococcus spp (15.4%). Adherence with the vancomycin dosing protocol was significantly higher in the postintervention period (90.8% vs 55%; P ≤ .001). By multivariate analysis, an AUC-based dosing protocol with MT support was the sole predictor for adherence with the vancomycin dosing protocol (adjusted odds ratio, 10.31; 95% confidence interval, 4.54–23.45; P ≤ .001). The 30-day mortality rate was significantly lower during the postintervention period (8.3% vs 20%; P = .015). Conclusions: AUC-based dosing protocol with MT support significantly improved adherence with vancomycin dosing protocol and was associated with a lower 30-day mortality rate.

scholarly journals Evidence for Establishing the Clinical Breakpoint of Cefquinome against Haemophilus Parasuis in China

Pathogens ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 105
Author(s):  
Kun Mi ◽  
Da Sun ◽  
Mei Li ◽  
Haihong Hao ◽  
Kaixiang Zhou ◽  
...  
Keyword(s):  
Monte Carlo Simulation ◽  
Antibacterial Activity ◽  
Inhibitory Concentration ◽  
High Morbidity ◽  
Haemophilus Parasuis ◽  
Wild Type ◽  
Time Curve ◽  
Resistance Change ◽  
Concentration Time ◽  
Clinical Experiments

Haemophilus parasuis can cause high morbidity and mortality in swine. Cefquinome possesses excellent antibacterial activity against pathogens causing diseases of the respiratory tract. This study aimed to establish the clinical breakpoint (CBP) of cefquinome against H. parasuis and to monitor the resistance change. Referring to the minimum inhibitory concentration (MIC) distribution of cefquinome against 131 H. parasuis isolates, the MIC50 and MIC90 were determined to be 0.125 and 1 μg/mL, respectively. And the epidemiological cutoff (ECOFF) value was 1 μg/mL. HPS42 was selected as a representative strain for the pharmacodynamic (PD) experiment, pharmacokinetic (PK) experiment and clinical experiments. The PK/PD index values, area under concentration-time curve (AUC)/MIC, of the bacteriostatic, bactericidal, and bacterial elimination effects were 23, 41, and 51 h, respectively. The PK/PD cutoff was calculated as 0.125 μg/mL by Monte Carlo simulation (MCS), and the clinical cutoff was 0.25−4 μg/mL by WindoW. Combing these three values, the CBP of cefquinome against H. parasuis was found to be 1 μg/mL. In conclusion, this was the first study to integrate various cutoffs to establish the CBP in the laboratory. It is helpful to distinguish wild type H. parasuis and reduce the probability of treatment failure.

scholarly journals 1326. Vancomycin Area Under the Concentration-Time Curve (AUC) Estimation Using a Bayesian Approach Versus First-Order Pharmacokinetic Equations: A Pilot Study

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S673-S673
Author(s):  
Jeffrey Pearson ◽  
Yazed S Alsowaida ◽  
B S Pharm ◽  
David W Kubiak ◽  
Mary P Kovacevic ◽  
...  
Keyword(s):  
Pilot Study ◽  
Median Time ◽  
Bayesian Modeling ◽  
Surgical Prophylaxis ◽  
Time Curve ◽  
Team Members ◽  
First Order ◽  
Concentration Time ◽  
Study Team ◽  
Auc Estimation

Abstract Background Current guidelines endorse area under the concentration-time curve (AUC)-based monitoring over trough-only monitoring for systemic vancomycin. Vancomycin AUC can be estimated using either Bayesian modeling software or first-order pharmacokinetic (PK) calculations. The objective of this pilot study was to evaluate and compare the efficiency and feasibility of these two approaches for calculating the estimated vancomycin AUC. Methods A single-center crossover study was conducted in four medical/surgical units at Brigham and Women’s Hospital over a 3-month time period. All adult patients who received vancomycin were included. Patients were excluded if they were receiving vancomycin for surgical prophylaxis, were on hemodialysis, if vancomycin was being dosed by level, or if vancomycin levels were never drawn. The primary endpoint was the amount of time study team members spent calculating the estimated AUC and determining regimen adjustments with Bayesian modeling compared to first-order PK calculations. Secondary endpoints included the number of vancomycin levels drawn and the percent of those drawn that were usable for AUC calculations. Results One hundred twenty-four patients received vancomycin during the study, of whom 47 met inclusion criteria. The most likely reasons for exclusion were receiving vancomycin for surgical prophylaxis (n=40) or never having vancomycin levels drawn (n=32). The median time taken to assess levels in the Bayesian arm was 9.3 minutes [interquartile range (IQR) 7.8-12.4] versus 6.8 minutes (IQR 4.8-8.0) in the 2-level PK arm (p=0.004). However, if Bayesian software is integrated into the electronic health record (EHR), the median time to assess levels was 3.8 minutes (IQR 2.3-6.8, p=0.019). In the Bayesian arm, 30 of 34 vancomycin levels (88.2%) were usable for AUC calculations, compared to 28 of 58 (48.3%) in the 2-level PK arm. Conclusion With EHR integration, the use of Bayesian software to calculate the AUC was more efficient than first-order PK calculations. Additionally, vancomycin levels were more likely to be usable in the Bayesian arm, thereby avoiding delays in estimating the vancomycin AUC. Disclosures All Authors: No reported disclosures

scholarly journals Ginsenoside Absorption Rate and Extent Enhancement of Black Ginseng (CJ EnerG) over Red Ginseng in Healthy Adults

Pharmaceutics ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 487
Author(s):  
Saebyul Yoo ◽  
Bom-I Park ◽  
Do-hyun Kim ◽  
Sooyoung Lee ◽  
Seung-hoon Lee ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Molecular Weight ◽  
Absorption Rate ◽  
Systemic Exposure ◽  
Red Ginseng ◽  
Double Blind ◽  
Time Curve ◽  
Concentration Time ◽  
Black Ginseng ◽  
Clinically Significant

Red ginseng (RG) and black ginseng (BG, CJ EnerG) were prepared from fresh ginseng using one and nine cycles of steaming and drying, respectively. This process reduces the molecular weight (MW) of ginsenoside-active compounds in ginseng by removing sugar moieties from their dammaranes. We compared the pharmacokinetic characteristics of ginsenosides between BG comprising mainly low-MW ginsenosides (Rg3, Rg5, Rk1, and Rh1) and RG that predominantly contains high-MW ginsenosides (Rb1, Rb2, Rc, Rd, Re, and Rg1). The safety profiles and tolerability were also studied using a randomized, double-blind, single-dose, crossover clinical trial. A combination of Rb1, Rg1, and Rg3, well-known representative and functional RG components, exhibited a 1-h faster absorption rate (Tmax) and 58% higher exposure (24-h area under the concentration–time curve, AUC24) in BG than in RG. Furthermore, the combination of Rg3, Rg5, and Rk1, the major and most efficient components in BG, displayed 824% higher absorption (AUC24) in BG than in RG. The total ginsenoside showed a 5-h rapid intestinal absorption (Tmax) and 79% greater systemic exposure (AUC24) in BG than in RG. No clinically significant findings were observed in terms of safety or tolerability. Thus, BG extract was more effective than RG extract.

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