Dose Finding and Food Effect Studies of a Novel Abiraterone Acetate Formulation for Oral Suspension in Comparison to a Reference Formulation in Healthy Male Subjects

Currently approved formulations of the androgen synthesis inhibitor abiraterone acetate (AA) consist of multiple tablets administered daily in a fasted state. Removing the food effect and switching to a suspension formulation is expected to improve the pharmacokinetic profile and facilitate drug administration for patients with late-stage prostate cancer. Two four-sequence, four-period randomized crossover investigations were undertaken to establish the pharmacokinetic profiles of single doses of commercially available Zytiga®, as the reference AA (R-AA), and a novel tablet for oral suspension (TOS). Four single doses of TOS (from 62.5 to 250 mg) were compared in study C01, and two single doses each of TOS (250 mg) and R-AA (1000 mg) were compared under fasted and fed (modified fasted for R-AA) conditions in C02. Plasma concentrations of abiraterone over time were measured, and pharmacokinetic parameters were calculated. Each doubling of the dose of TOS was associated with a greater than 3-fold increase in exposure. A single dose of TOS (250 mg) exhibited similar exposure over 24 h, whether given fasted (625 ng × h/mL) or fed (485 ng × h/mL). A single dose of TOS (250 mg) was associated with higher (fasted, p = 0.028) or equivalent exposure (fed) compared to 1000 mg R-AA fasted (532 ng × h/mL). Substantially higher exposures were seen with 1000 mg R-AA under modified fasted conditions compared to TOS, irrespective of prandial status (p < 0.001). TOS was generally safe and well tolerated in the study. A 250 mg dose of a novel AA formulation for oral suspension demonstrated bioequivalence to 1000 mg R-AA under fasted conditions. This novel TOS formulation also addresses some of the limitations of current AA treatment, including low bioavailability, high variability in systemic exposure and a large food effect. It may offer an alternative for patients with dysphagia or discomfort with swallowing large pills.

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Minireview: Androgen Metabolism in Castration-Resistant Prostate Cancer

Molecular Endocrinology ◽

10.1210/me.2013-1007 ◽

2013 ◽

Vol 27 (5) ◽

pp. 708-714 ◽

Cited By ~ 35

Author(s):

Nima Sharifi

Keyword(s):

Prostate Cancer ◽

Abiraterone Acetate ◽

Castration Resistant Prostate Cancer ◽

Synthesis Inhibitor ◽

Androgen Independence ◽

Androgen Synthesis ◽

Androgen Receptor Antagonist ◽

Castration Resistant ◽

Hormonal Therapies ◽

Additional Clinical Benefit

Abstract The decades-old terminology of androgen independence has been replaced in recent years with castration-resistant prostate cancer. Biological and clinical evidence have together conspired to support the use of this revised terminology by demonstrating that in the vast majority of cases tumors are neither truly depleted of androgens, nor are they free of the requirement for androgens to sustain growth and progression. Abiraterone acetate, an androgen synthesis inhibitor, and enzalutamide, a potent androgen receptor antagonist, both exploit the continued requirement for androgens. A central question, given the therapeutic gains enabled by further suppression of the androgen axis with these newer agents, is whether there may be additional clinical benefit gained by moving the goal posts of androgen suppression even further. The answer lies in part with the mechanisms utilized by tumors that enable resistance to these therapies. The aims of this review were to give a broad outline of steroidogenesis in prostate cancer and to highlight recent developments in understanding resistance to hormonal therapies.

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Consequences of Different Corticosteroids on Serum Potassium and Prostate-Specific Antigen in Patients Receiving Abiraterone for Castration-Resistant Prostate Cancer: A Retrospective Observational Study

Clinical Medicine Insights Oncology ◽

10.1177/1179554917737736 ◽

2017 ◽

Vol 11 ◽

pp. 117955491773773 ◽

Cited By ~ 1

Author(s):

Masaomi Tatsuzawa ◽

Ryuichi Ogawa ◽

Naoki Kinjo ◽

Soan Kim ◽

Fumitaka Shimizu ◽

...

Keyword(s):

Prostate Cancer ◽

Prostate Specific Antigen ◽

Serum Potassium ◽

Medical Records ◽

Specific Antigen ◽

Abiraterone Acetate ◽

Castration Resistant Prostate Cancer ◽

Synthesis Inhibitor ◽

Androgen Synthesis ◽

Castration Resistant

Background: Abiraterone acetate is an androgen synthesis inhibitor approved for the treatment of castration-resistant prostate cancer (CRPC). Although co-administration of either prednisone or prednisolone at 10 mg/d has been recommended to reduce the risk of abiraterone-induced hyperaldosteronism (notably hypokalemia) and to give adjunctive pain relief effects, whether these glucocorticoids can be substituted by dexamethasone remains unknown. Methods: We performed a retrospective review of medical records of patients who were given abiraterone for the treatment of CRPC with either prednisolone (ABI/PSL) 10 mg/d or dexamethasone (ABI/DEX) 0.5 or 1 mg/d between 2014 and 2017 in Juntendo University Nerima Hospital. Demographic and biochemical data including prostate-specific antigen (PSA) level were retrieved from the electronic medical records. Results: Fifty-three eligible patients (27 in ABI/PSL group and 26 in ABI/DEX group) were extracted from the records. Both groups showed no significant changes in serum potassium level before and after starting treatment. In the ABI/PSL group, 12 patients (46%) showed elevations of PSA and 7 patients (27%) discontinued treatment within 3 months. In contrast, in the ABI/DEX group, only 6 patients (25%) showed elevations of PSA and 3 patients (13%, all were given dexamethasone 1 mg/d) discontinued treatment. Conclusions: Dexamethasone and prednisolone may be equally effective in preventing abiraterone-induced hypokalemia.

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A phase III trial comparing atezolizumab with enzalutamide vs enzalutamide alone in patients with metastatic castration-resistant prostate cancer (mCRPC).

Journal of Clinical Oncology ◽

10.1200/jco.2017.35.15_suppl.tps5090 ◽

2017 ◽

Vol 35 (15_suppl) ◽

pp. TPS5090-TPS5090 ◽

Cited By ~ 1

Author(s):

Thomas Powles ◽

Karim Fizazi ◽

Silke Gillessen ◽

Charles G. Drake ◽

Dana E. Rathkopf ◽

...

Keyword(s):

Clinical Trial ◽

Locally Advanced ◽

Abiraterone Acetate ◽

Phase Iii ◽

Castration Resistant Prostate Cancer ◽

Effective Treatment Option ◽

Synthesis Inhibitor ◽

Eligibility Criteria ◽

Androgen Synthesis ◽

Ecog Ps

TPS5090 Background: In the past decade, several therapies have been approved for patients (pts) with mCRPC, including the androgen receptor (AR) antagonist enzalutamide (enza) and the androgen synthesis inhibitor abiraterone acetate (abi). Despite these advances, most pts experience disease progression and there are inadequate data to guide the sequencing of agents to optimize outcomes. Pts with mCRPC who progress on enza have increased circulating PD-L1/PD-L2–positive dendritic cells compared with enza-naive pts or pts who are still responding to treatment (Bishop et al. Oncotarget. 2014). In two recent studies, PSA and radiographic responses were observed in mCRPC pts treated with a PD-L1/PD-1 pathway inhibitor with or without enza (Graff et al. Oncotarget. 2016; Hansen et al. Ann Oncol. 2016). Atezolizumab (atezo) is an anti–PD-L1 monoclonal antibody that inhibits the interaction between PD-L1 and its receptors, PD-1 and B7.1, enhancing T-cell responses and improving anti-tumor activity. Taken together, this suggests that the combination of atezo and enza may provide an effective treatment option for mCRPC pts. Methods: A Phase III randomized, multicenter, clinical trial (NCT03016312) is being conducted to evaluate the efficacy and safety of atezo with enza compared with enza alone in mCRPC pts who have received prior abi treatment and have progressed on, are ineligible for, or have refused a taxane regimen. Eligibility criteria include mCRPC or locally advanced, incurable CRPC and ECOG PS 0-1. Exclusion criteria include CNS metastasis, autoimmune disease, history of seizures, prior immunotherapy and prior treatment with enza or any other newer AR antagonists. Pts will be randomized 1:1 to receive atezo 1200 mg q3w and enza 160 mg qd or enza alone. The primary endpoint is OS, and secondary endpoints include PSA response rate, rPFS, ORR and safety. Exploratory biomarkers associated with responses to atezo and enza will be evaluated in tumor tissue collected at baseline and progression. Approximately 550 pts will be enrolled at 150 sites globally. Clinical trial information: NCT03016312.

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Bioequivalence of levamlodipine besylate tablets in healthy Chinese subjects: A single-dose and two-period crossover randomized study

10.21203/rs.3.rs-47842/v2 ◽

2020 ◽

Author(s):

Li Xin ◽

Chenjing Wang ◽

Ting Li ◽

Yanping Liu ◽

Shuqin Liu ◽

...

Keyword(s):

Single Dose ◽

Randomized Study ◽

Plasma Concentrations ◽

Bioequivalence Study ◽

Pharmacokinetic Parameters ◽

Open Label ◽

Liquid Chromatography Tandem Mass ◽

The Mean ◽

Healthy Chinese ◽

Chinese Subjects

Abstract Background: Levamlodipine, a calcium channel blocker, has been show act as a cardiovascular drug. To compare the pharmacokinetic parameters between levamlodipine (test formulation) at a single dose of 5 mg and amlodipine (reference formulation) at a single dose of 10 mg, the bioequivalence study was carried out.Methods: A single-dose randomized, open-label, two-period crossover study was designed in healthy Chinese subjects. 48 subjects were divided into fasted and fed groups equally. The subjects randomly received the test or reference formulations at the rate of 1:1. Following a 21-day washout period, the alternative formulations were received. The blood samples were collected at 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 24, 36, 48, 72, 96, 120, 144, 168 hours later. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was applied to determine the plasma concentrations of levamlodipine. Adverse events were recorded.Results: The 90% confidence intervals (CIs) of the ratio of geometric means (GMRs) of Cmax, AUC0-t, and AUC0-∞ under both fasted and fed conditions were within the prespecified bioequivalence limits between 80~125%. Under fasted conditions, 24 subjects were enrolled and completed the study. The mean Cmax was (2.70±0.49) ng/mL, AUC0-t was (141.32±36.24) ng×h/mL and AUC0-∞ was (157.14±45.65) ng×h/mL after a single dose of 5 mg levamlodipine. The mean Cmax was (2.83±0.52) ng/mL, AUC0-t was (153.62±33.96) ng×h/mL and AUC0-∞ was (173.05±41.78) ng×h/mL after a single dose of 10 mg amlodipine. Under fed conditions, 24 subjects were enrolled and completed the study. The mean Cmax was (2.73±0.55) ng/mL, AUC0-t was (166.93±49.96) ng×h/mL and AUC0-∞ was (190.99±70.89) ng×h/mL after a single dose of 5 mg levamlodipine. The mean Cmax was (2.87±0.81) ng/mL AUC0-t was (165.46±43.58) ng×h/mL and AUC0-∞ was (189.51±64.70) ng×h/mL after a single dose of 10 mg amlodipine. Serious adverse event was not observed.Conclusion: The trial confirmed that levamlodipine at a single dose of 5 mg and amlodipine at a single dose of 10 mg were bioequivalent under both fasted condition and fed condition.Trial registration: Cinicaltrials, NCT04411875. Registered 3 June 2020 - Retrospectively registered, https://register.clinicaltrials.gov/prs/app/action/SelectProtocol?sid=S0009W1Q&selectaction=Edit&uid=U00050YQ&ts=3&cx=-6iqkm8

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Gender differences in concentration of itraconazole and hydroxyitraconazole

Naucni casopis urgentne medicine - Halo 194 ◽

10.5937/halo27-30859 ◽

2021 ◽

Vol 27 (1) ◽

pp. 7-18

Author(s):

Tijana Stanojković ◽

Milijana Miljković ◽

Nemanja Rančić ◽

Aleksandra Kovačević ◽

Viktorija Dragojević-Simić

Keyword(s):

Single Dose ◽

Plasma Concentrations ◽

Pharmacokinetic Analysis ◽

Pharmacokinetic Parameters ◽

Time Intervals ◽

Chromatography Method ◽

Oral Application ◽

First Pass ◽

Liquid Chromatography Method ◽

Pass Through

Introduction: Itraconazole is an antifungal drug belonging to the triazole group. After oral application, it is rapidly absorbed, but its bioavailability is reduced due to an intensive first-pass through the liver metabolism effect. A large number of metabolites (the most important of which is hydroxyitraconazole) are produced by isoform CYP3A4 of cytochrome P450. The variability of itraconazole pharmacokinetics is the result of numerous factors that have not yet been fully clarified. Our study aimed to investigate the influence of gender on itraconazole and hydroxyitraconazole plasma concentrations in healthy adults after an oral application of a single dose of itraconazole. Methods: Pharmacokinetic analysis was performed after oral administration of itraconazole in a single dose of 100 mg to 22 male and 16 female healthy volunteers. Blood samples were collected before taking the drug and at appropriate time intervals up to 72 hours later. Itraconazole and hydroxyitraconazole concentrations were determined using a validated liquid chromatography method with mass spectrometric detection (LC-MS/MS) and their pharmacokinetic parameters were calculated by using the Kinetica programme, version 5.0: Cmax, Tmax, PIK (0-72), PIK (0-∞), T1/2, and Ke. Results: The median values of both itraconazole and hydroxyitraconazole were lower in women in comparison to men during the whole period of observation. Moreover, median values of Cmax, PIK(0-72) and PIK(0-∞) parameters were also significantly lower in women, concerning both itraconazole (p=0.005, 0.036 and 0.036, respectively) and its metabolite (p=0.004, 0.010 and 0.044, respectively). Elimination parameters - T1/2 and Ke did not differ between genders. Conclusion: Women were less exposed to itraconazole and its active metabolite than men following an oral application of the drug, possibly as a result of lower bioavailability due to a more intense pre-systemic metabolism, as a result of a higher expression and/or activity of the isoform enzyme, which metabolises itraconazole, and which would need to be confirmed by pharmacogenomic analysis.

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178 Single-Dose Pharmacokinetics of Amphetamine Extended-Release Tablet Compared with Amphetamine Extended-Release Oral Suspension

CNS Spectrums ◽

10.1017/s1092852920000930 ◽

2020 ◽

Vol 25 (2) ◽

pp. 312-313

Author(s):

Barry K. Herman ◽

Judith C. Kando ◽

Thomas King ◽

Antonio Pardo

Keyword(s):

Single Dose ◽

Extended Release ◽

Food Effect ◽

Geometric Mean ◽

Oral Suspension ◽

Post Dose ◽

Comparative Bioavailability ◽

Extended Release Tablet ◽

Funding Acknowledgements ◽

Release Tablet

Abstract:Objectives:Evaluate comparative bioavailability of single-dose amphetamine extended-release tablet (AMPH ER TAB, Tris Pharma, Inc., Monmouth Junction, NJ) 20 mg, swallowed whole or chewed and amphetamine extended-release oral suspension (AMPH EROS) 2.5 mg/mL; and evaluate whether a PK food effect exists on AMPH ER TAB (contains a 3.2:1 ratio of d- to l-amphetamine).METHODS:Healthy volunteers (18-55 yr) were randomized to 1 dose of AMPH ER TAB 20 mg swallowed (fasted), chewed (fed/fasted), or 20 mg AMPH EROS (fasted).A crossover design was used. Samples were collected each period pre-dose and at time points to 60 h post-dose. D-and l-amphetamine were measured, and PK was calculated (90% CIs of the ratios of the geometric mean plasma levels) for Cmax, AUCt, and AUC0∞. Comparative bioavailability was determined when ratios were within 80 and 125%. Safety was also assessed.RESULTS:32 subjects completed the study. Based on the calculated bioavailability ratios, for AMPH ER TAB swallowed vs. AMPH EROS fasted: d-amphetamine total and peak exposures were found to be similar: AUC0-t: 100.68-108.08%, AUC0-∞:101.47-109.52%, Cmax: 98.10-103.17%. For l-amphetamine, the total and peak exposures were similar: AUC0-t: 100.31-108.57%, AUC0-∞:101.27-111.09%, Cmax: 98.2-103.37%.AMPH ER TAB chewed vs. AMPH EROS fasted: For d-amphetamine, the total and peak exposures were similar: AUC0-t: 99.23-106.62%, AUC0-∞: 99.58-107.59%, Cmax: 99.91-105.14%. For l-amphetamine, the total and peak exposure was similar: AUC0-t: 98.16-106.35%, AUC0-∞: 98.44-108.11%, Cmax: 99.53-104.75%.Food effect: AMPH ER TAB, chewed, fasted vs. fed: For d-amphetamine, the total and peak exposure was similar: AUC0-t: 92.57-99.49%, AUC0-∞: 91.12-98.48%, Cmax: 94.22-99.17%.For l-amphetamine, the total and peak exposure was similar: AUC0-t: 91.27-98.91%, AUC0-∞: 88.44-97.17%, Cmax: 94.52-99.50%).No serious AEs were reported during the conduct of this study, and the AE profiles were observed to be similar in frequency of events and severity to other amphetamine formulations used in ADHD.CONCLUSIONS:Bioavailability of single dose of AMPH ER TAB for both d- and l-amphetamine was comparable, swallowed whole or chewed, to an equivalent 20 mg dose of the reference product AMPH EROS, 2.5 mg/mL fasted, and showed equivalent peak and overall exposure.No food effect was observed for AMPH ER TAB administered chewed. All AEs were mild in severity and AE profiles were similar to other amphetamine formulations used for treatment of ADHD.Funding Acknowledgements:Tris Pharma, Inc.

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Clinical pharmacodynamics of continuous infusion teniposide: systemic exposure as a determinant of response in a phase I trial.

Journal of Clinical Oncology ◽

10.1200/jco.1987.5.7.1007 ◽

1987 ◽

Vol 5 (7) ◽

pp. 1007-1014 ◽

Cited By ~ 71

Author(s):

J H Rodman ◽

M Abromowitch ◽

J A Sinkule ◽

F A Hayes ◽

G K Rivera ◽

...

Keyword(s):

Continuous Infusion ◽

Plasma Concentrations ◽

Systemic Exposure ◽

Pharmacokinetic Parameters ◽

Pharmacokinetic Variability ◽

Significant Relationships ◽

Clinical Responses ◽

The Mean ◽

Dose Levels ◽

Severe Mucositis

Teniposide (VM-26) is an effective anticancer drug usually administered as a short infusion in doses of 150 to 165 mg/m2. The objectives of the trial reported here were to evaluate clinical responses and assess pharmacokinetic parameters as a determinant of outcome when VM-26 was administered as a 72-hour continuous infusion (CI) with doses escalated from 300 to 750 mg/m2 per course. Twenty-eight patients with recurrent leukemia, lymphoma, or neuroblastoma received 53 courses of CI VM-26 and 16 had measurable responses. There were two partial remissions and one stable disease among seven neuroblastoma patients and 13 of 21 leukemia/lymphoma patients had oncolytic responses (greater than or equal to 75% decrease in circulating blasts). Toxicity included moderate to severe mucositis and myelosuppression. Pharmacokinetic parameters determined during 35 courses administered to 23 patients were highly variable. Clearance (CI) ranged between 3.7 and 43.8 ml/min/m2, resulting in VM-26 plasma concentrations from 2.8 to 30.6 mg/L across all dose levels. The interpatient pharmacokinetic variability reflected in CI and VM-26 steady state concentrations (Css), obscured any dose-response relationship. However, when pharmacokinetic parameters for responding and nonresponding patients were compared, statistically significant relationships were observed. For responders, the mean Css was 15.2 mg/L and mean CI was 12.1 mL/min/m2; for nonresponders, mean Css was 6.2 mg/L (P less than .01) and mean CI was 21.3 mL/min/m2 (P less than .05). Thus, patients with higher CI and lower Css were less likely to respond. Clinical responses occurred in ten of ten patients with Css greater than 12 mg/L, and only five of 13 patients with Css less than 12 mg/L (P less than .01). In this study, interpatient pharmacokinetic variability yielded a four- to sixfold difference in intensity of systemic exposure (Css) within the same dose level, which was an important determinant of clinical response. These data indicate that achieving a VM-26 target concentration for individual patients could ensure an increased intensity of systemic exposure in patients with a high CI and improve the likelihood of effective therapy.

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Single-dose pharmacokinetics of amphetamine extended-release tablets compared with amphetamine extended-release oral suspension

CNS Spectrums ◽

10.1017/s1092852919001676 ◽

2020 ◽

Vol 25 (6) ◽

pp. 774-781

Author(s):

Antonio Pardo ◽

Judith C. Kando ◽

Thomas R. King ◽

Eman Rafla ◽

Barry K. Herman

Keyword(s):

Single Dose ◽

Adverse Events ◽

Extended Release ◽

Food Effect ◽

Relative Bioavailability ◽

Oral Suspension ◽

Plasma Samples ◽

Serious Adverse Events ◽

Time Points ◽

Extended Release Tablet

AbstractObjectiveEvaluate the relative bioavailability of single-dose amphetamine extended-release tablet (AMPH ER TAB) 20 mg, swallowed whole or chewed, and amphetamine extended-release oral suspension (AMPH EROS) 2.5 mg/mL; evaluate food effect on AMPH ER TAB.MethodsHealthy volunteers (18–55 years) were randomized to 1 dose of AMPH ER TAB 20 mg swallowed (fasted), chewed (fed/fasted), or 20 mg AMPH EROS (fasted). A crossover study design was used. Plasma samples were collected each period predose and at time points to 60 hours postdose. d- and l-amphetamine were measured and pharmacokinetic (PK) was calculated (90% confidence intervals of the ratios of the plasma levels) for AUC0-t, AUC0-∞, and Cmax. Comparative relative bioavailability between formulations was determined when ratios were within 80% and 125%. Safety was also assessed.ResultsThirty-two subjects completed the study. AMPH ER TAB swallowed versus AMPH EROS (fasted): for d- and l-amphetamine, the total and peak exposure was similar: d: AUC0-t: 100.68% to 108.08%, AUC0-∞: 101.47% to 109.52%, Cmax: 98.10% to 103.17%; l: AUC0-t: 100.31% to 108.57%, AUC0-∞: 101.27% to 111.09%, Cmax: 98.2% to 103.37%. For d- and l-amphetamine when the tablet is swallowed whole, Tmax was 5.00 hours (with a range of 2.00–9.00 hours). AMPH ER TAB chewed versus AMPH EROS (fasted): for d- and l-amphetamine, the total and peak exposure was similar: d: AUC0-t: 99.23% to 106.62%, AUC0-∞: 99.58% to 107.59%, Cmax: 99.91% to 105.14%; l: AUC0-t: 98.16% to 106.35%, AUC0-∞: 98.44% to 108.11%, Cmax: 99.53% to 104.75%. For d- and l-amphetamine when the tablet has been chewed, Tmax was 5.00 hours (with a range of 3.00-7.00 hours). PK results were similar for patients in the fasted and fed groups, indicative of no presence of food effect. No serious adverse events (AEs) were reported, overall AE profiles between the tablet and oral suspension were comparable without any unanticipated safety concerns.ConclusionsSingle doses of AMPH ER TAB for both d- and l-amphetamine demonstrated comparable bioavailability to a 20 mg dose of AMPH EROS, 2.5 mg/mL under fasted conditions when chewed and swallowed whole, and demonstrated equivalent peak and overall exposure without apparent food effect. AMPH ER TAB was well-tolerated and consistent with adverse events noted in other amphetamine formulations.

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Effects of Vitamin D Plus Calcium Supplements on Pharmacokinetics of Isoflavones in Thai Postmenopausal Women

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2011/895471 ◽

2011 ◽

Vol 2011 ◽

pp. 1-7 ◽

Cited By ~ 7

Author(s):

Supanimit Teekachunhatean ◽

Paveena Pongnad ◽

Noppamas Rojanasthein ◽

Maleeya Manorot ◽

Chaichan Sangdee

Keyword(s):

Vitamin D ◽

Single Dose ◽

Plasma Concentration ◽

Postmenopausal Women ◽

Plasma Concentrations ◽

Pharmacokinetic Parameters ◽

Calcium Supplements ◽

Maximal Plasma Concentration ◽

Maximal Plasma ◽

To Receive

The objective of this study was to determine the effects of vitamin D3plus calcium supplements (D3-calcium) on pharmacokinetics of isoflavones in Thai postmenopausal women. This study was an open-labeled, randomized three-phase crossover study. Twelve healthy subjects were randomized to receive one of the following regimens: (a) a single dose of isoflavones, (b) a single dose of isoflavones, and D3-calcium, or (c) continuous D3-calcium for 7 days followed by a single dose of isoflavones on the 8th day. After a washout period, subjects were switched to receive the 2 remaining regimens according to their randomized sequences. Blood samples were collected before dose and at specific time points until 32 hours after isoflavone administration. Plasma was treated with β-glucuronidase/sulfatase to hydrolyze glucuronide and sulfate conjugates of daidzein and genistein. Plasma concentrations of daidzein and genistein were determined by high performance liquid chromatography. The estimated pharmacokinetic parameters of isoflavones were time to maximal plasma concentration (Tmax), maximal plasma concentration (Cmax), half-life (t1/2) and area under the plasma concentration-time curve (AUC).Tmaxof daidzein and genistein after regimen B was significantly longer than that of regimen A. Other pharmacokinetic parameters of daidzein and genistein obtained following the three regimens were not significantly different.

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Prospective, Controlled Study of Acyclovir Pharmacokinetics in Obese Patients

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02010-15 ◽

2016 ◽

Vol 60 (3) ◽

pp. 1830-1833 ◽

Cited By ~ 8

Author(s):

R. Brigg Turner ◽

Aaron Cumpston ◽

Michael Sweet ◽

Frank Briggs ◽

Douglas Slain ◽

...

Keyword(s):

Body Weight ◽

Single Dose ◽

Plasma Concentrations ◽

Systemic Exposure ◽

Ideal Body Weight ◽

Normal Weight ◽

Controlled Study ◽

Pharmacokinetic Analysis ◽

Obese Patients ◽

Time Curve

The current recommendations for intravenous (i.v.) acyclovir dosing in obese patients suggest using ideal body weight (IBW) rather than total body weight (TBW). To our knowledge, no pharmacokinetic analysis has validated this recommendation. This single-dose pharmacokinetic study was conducted in an inpatient oncology population. Enrollment was conducted by 1:1 matching of obese patients (>190% of IBW) to normal-weight patients (80 to 120% of IBW). All patients received a single dose of i.v. acyclovir, 5 mg/kg, infused over 60 min. Consistent with current recommendations, IBW was used for obese patients and TBW for normal-weight patients. Serial plasma concentrations were obtained and compared. Seven obese and seven normal-weight patients were enrolled, with mean body mass indexes of 45.0 and 22.5 kg/m2, respectively. Systemic clearance was substantially higher in the obese than normal-weight patients (mean, 19.4 ± 5.3 versus 14.3 ± 5.4 liters/h;P= 0.047). Area under the concentration-time curve was lower in the obese patients (15.2 ± 2.9 versus 24.0 ± 9.4 mg · h/liter;P= 0.011), as was maximum concentration (5.8 ± 0.9 versus 8.2 ± 1.3 mg/liter;P= 0.031). Utilization of IBW for dose calculation of i.v. acyclovir in obese patients leads to lower systemic exposure than dosing by TBW in normal-weight patients. While not directly evaluated in this study, utilization of an adjusted body weight for dose determination appears to more closely approximate the exposure seen in normal-weight patients. (This study has been registered at ClinicalTrials.gov under registration no. NCT01714180.)

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