scholarly journals Safety and Pharmacokinetics of Bevirimat (PA-457), a Novel Inhibitor of Human Immunodeficiency Virus Maturation, in Healthy Volunteers

2007 ◽  
Vol 51 (9) ◽  
pp. 3063-3066 ◽  
Author(s):  
David E. Martin ◽  
Robert Blum ◽  
John Wilton ◽  
Judy Doto ◽  
Hal Galbraith ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Oral Administration ◽  
Half Life ◽  
Peak Plasma ◽  
Plasma Concentrations ◽  
Pharmacokinetic Parameters ◽  
Double Blind Study ◽  
Immunodeficiency Virus ◽  
Oral Doses

ABSTRACT Bevirimat (BVM; formerly known as PA-457) is a novel inhibitor of human immunodeficiency virus (HIV) maturation that is being developed for the treatment of HIV infection. The pharmacokinetics of this agent in healthy male volunteers were studied in a randomized, double-blind study in which the participants received single oral doses of placebo (n = 8) or escalating doses of BVM at 25, 50, 100, or 250 mg (n = 6 per dose); escalation was performed only after the pharmacokinetics and safety of the preceding dose had been evaluated. Plasma was collected over 480 h after dosing and urine was collected over 48 h after dosing for determination of the values of pharmacokinetic parameters. BVM was well absorbed after oral administration, with peak plasma concentrations being achieved 1 to 3 h after dosing. The half-life was 60 to 80 h. The exposure assessed by determination of the peak concentration and the area under the concentration-time curve was dose proportional. Single oral doses of BVM were well tolerated: there were no dose-limiting toxicities, and no serious adverse events were reported. These findings suggest that that BVM offers a favorable pharmacokinetic profile, with predictable pharmacokinetics following the oral administration of single doses. The long half-life of BVM may facilitate once-daily dosing.

scholarly journals Pharmacokinetic Study of Human Immunodeficiency Virus Protease Inhibitors Used in Combination with Amprenavir

2001 ◽  
Vol 45 (12) ◽  
pp. 3663-3668 ◽  
Author(s):  
Brian M. Sadler ◽  
Catherine Gillotin ◽  
Yu Lou ◽  
Joseph J. Eron ◽  
William Lang ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Steady State ◽  
Protease Inhibitors ◽  
Pharmacokinetic Study ◽  
Peak Plasma ◽  
Peak Plasma Concentration ◽  
Plasma Concentrations ◽  
Pharmacokinetic Parameters ◽  
Open Label ◽  
Immunodeficiency Virus

ABSTRACT In an open-label, randomized, multicenter, multiple-dose pharmacokinetic study, we determined the steady-state pharmacokinetics of amprenavir with and without coadministration of indinavir, nelfinavir, or saquinavir soft gel formulation in 31 human immunodeficiency virus type 1-infected subjects. The results indicated that amprenavir plasma concentrations were decreased by saquinavir soft gel capsule (by 32% for area under the concentration-time curve at steady state [AUCss] and 37% for peak plasma concentration at steady state [C max,ss]) and increased by indinavir (33% for AUCss). Nelfinavir significantly increased amprenavir minimum drug concentration at steady state (by 189%) but did not affect amprenavir AUCss orC max,ss. Nelfinavir and saquinavir steady-state pharmacokinetics were unchanged by coadministration with amprenavir compared with the historical monotherapy data. Concentrations of indinavir, coadministered with amprenavir, in plasma decreased in both single-dose and steady-state evaluations. The changes in amprenavir steady-state pharmacokinetic parameters, relative to those for amprenavir alone, were not consistent among protease inhibitors, nor were the changes consistent with potential interactions in CYP3A4 metabolism or P-glycoprotein transport. No dose adjustment of either protease inhibitor in any of the combinations studied is needed.

scholarly journals Preclinical pharmacokinetics and distribution to tissue of AG1343, an inhibitor of human immunodeficiency virus type 1 protease.

1996 ◽  
Vol 40 (1) ◽  
pp. 110-114 ◽  
Author(s):  
B V Shetty ◽  
M B Kosa ◽  
D A Khalil ◽  
S Webber
Keyword(s):  
Human Immunodeficiency Virus ◽  
Oral Administration ◽  
Tissue Distribution ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Oral Bioavailability ◽  
Plasma Concentrations ◽  
Immunodeficiency Virus ◽  
Hiv 1

AG1343, a potent inhibitor of human immunodeficiency virus type 1 (HIV-1) protease (Ki = 2 nM), was designed by protein structure-based drug design techniques. AG1343 has potent antiviral activity (95% effective dose = 0.04 microgram/ml) against a number of HIV-1 strains in acute and chronic models of infection. As part of its preclinical development, the oral bioavailability of AG1343 in rats, dogs, monkeys, and marmosets was determined and its tissue distribution in rats was evaluated. There were no major interspecies differences in AG1343 pharmacokinetics. Following intravenous administration, the elimination half-life of AG1343 ranged from 1 to 1.4 hr. The total volume of distribution (2 to 7 liters/kg) exceeded the volume of total body water, indicating extensive tissue distribution. Systemic clearance of AG1343 (1 to 4 liters/kg) in the different species corresponded to hepatic blood flow, suggesting possible hepatic involvement in the elimination of AG1343. Following oral administration, peak levels in plasma ranged from 0.34 microgram/ml after treatment with 10 mg/kg of body weight in the dog to 1.7 micrograms/ml after dosing with 50 mg/kg in the rat. Because of the slow absorption of AG1343, plasma concentrations of AG1343 exceeding that required for 95% inhibition of HIV-1 replication were maintained for up to 7 h after a single oral dose in all species evaluated. Average oral bioavailability of AG1343 ranged from 17% in the marmoset to 47% in the dog. Studies of distribution to tissue in the rat after oral administration of 14C-AG1343 established extensive distribution with concentrations in most tissues exceeding that found in plasma. Of particular significance were high levels of AG1343 equivalent in mesenteric lymph nodes (32.05 micrograms/g) and spleen tissue (9.33 micrograms/g). The major excretory route for AG1343 was via feces, with 100% of the dose recovered by 48 h. Results from these studies demonstrate that AG1343 is orally bioavailable and that levels in plasma in the therapeutic range are achievable and are maintained for prolonged periods in the animal models tested. On the basis of these and other findings, AG1343 was developed for further testing in human subjects.

scholarly journals Determination of Dosing Guidelines for Stavudine (2′,3′-Didehydro-3′-Deoxythymidine) in Children with Human Immunodeficiency Virus Infection

2001 ◽  
Vol 45 (3) ◽  
pp. 758-763 ◽  
Author(s):  
Sanjeev Kaul ◽  
Mark W. Kline ◽  
Joseph A. Church ◽  
Lisa M. Dunkle
Keyword(s):  
Human Immunodeficiency Virus ◽  
Body Weight ◽  
Pediatric Dose ◽  
Three Phase ◽  
Immunodeficiency Virus ◽  
Adult Dose ◽  
Total Body ◽  
Adult Exposure ◽  
Oral Doses

ABSTRACT The results of the development of dosing guidelines for stavudine in human immunodeficiency virus (HIV)-infected children are summarized. Included in the integrated analyses were 21 and 33 HIV-infected pediatric and adult patients, respectively, from three phase I-II studies. Data for 21 children and 18 adults who received intravenous doses of 0.125 to 2 and 0.5 to 1 mg/kg of body weight, respectively, were used for the determination of dosing guidelines; exposure data for 16 children and 15 adults who received oral doses of 1 to 2 and 0.5 to 1 mg/kg/day, respectively, were used to validate the dosing recommendations for children. Significant relationships were observed between total body clearance (in milliliters per minute) in children and adults combined and demographic parameters of age, body weight, and body surface area (R 2 = 0.77 to 0.80;P = 0.0001). Models of approximated pediatric dose based on clearance values and direct adult exposure yielded a stavudine dosage of 2 mg/kg/day for children of ≤30 kg of body weight and 1 mg/kg/day (adult dose) for children of >30 kg of body weight.

scholarly journals Absence of effect of trimethoprim-sulfamethoxazole on pharmacokinetics of zidovudine in patients infected with human immunodeficiency virus.

1996 ◽  
Vol 40 (1) ◽  
pp. 230-233 ◽  
Author(s):  
E Cañas ◽  
J Pachon ◽  
F Garcia-Pesquera ◽  
J R Castillo ◽  
P Viciana ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Oral Administration ◽  
Pharmacokinetic Parameters ◽  
Concomitant Therapy ◽  
Concentration Time ◽  
Immunodeficiency Virus ◽  
Standard Deviations

Pharmacokinetic parameters of zidovudine (ZDV) were not altered in 16 patients receiving concomitant therapy with ZDV and trimethoprim-sulfamethoxazole by oral administration. ZDV areas under the concentration-time curves were (means +/- standard deviations) 1.80 +/- 0.70 and 1.69 +/- 0.64 micrograms.h/ml in the absence and presence of trimethoprim-sulfamethoxazole, respectively. ZDV clearances were 1.57 +/- 0.61 and 1.74 +/- 0.66 liters/h/kg, respectively.

Pharmacokinetics of pimobendan following oral administration to New Zealand White rabbits (Oryctolagus cuniculus)

2022 ◽  
pp. 1-8
Author(s):  
Sarah M. Ozawa ◽  
David Sanchez-Migallon Guzman ◽  
Michelle G. Hawkins ◽  
Stephanie M. Diao ◽  
Acacia E. Masri ◽  
...  
Keyword(s):  
Critical Care ◽  
New Zealand ◽  
Oral Administration ◽  
Half Life ◽  
Maximum Concentration ◽  
Plasma Concentrations ◽  
Pharmacokinetic Parameters ◽  
Pilot Studies ◽  
New Zealand White Rabbits ◽  
Target Plasma Concentration

Abstract OBJECTIVE To determine the pharmacokinetics and potential adverse effects of pimobendan after oral administration in New Zealand White rabbits (Ocytolagus cuniculi). ANIMALS 10 adult sexually intact (5 males and 5 females) rabbits. PROCEDURES 2 pilot studies were performed with a pimobendan suspension or oral tablets. Eight rabbits received 7.5 mg of pimobendan (mean 2.08 mg/kg) suspended in a critical care feeding formula. Plasma concentrations of pimobendan and O-demethylpimobendan (ODMP) were measured, and pharmacokinetic parameters were calculated for pimobendan by noncompartmental analysis. Body weight, food and water consumption, mentation, urine, and fecal output were monitored. RESULTS Mean ± SD maximum concentration following pimobendan administration was 15.7 ± 7.54 ng/mL and was detected at 2.79 ± 1.25 hours. The half-life was 3.54 ± 1.32 hours. Plasma concentrations of pimobendan were detectable for up to 24 hours. The active metabolite, ODMP, was detected in rabbits for 24 to 36 hours. An adverse event occurred following administration of pimobendan in tablet form in 1 pilot study, resulting in death secondary to aspiration. No other adverse events occurred. CLINICAL RELEVANCE Plasma concentrations of pimobendan were lower than previously reported for dogs and cats, despite administration of higher doses, and had longer time to maximum concentration and half-life. Based on this study, 2 mg/kg of pimobendan in a critical care feeding formulation should maintain above a target plasma concentration for 12 to 24 hours. However, further studies evaluating multiple-dose administration as well as pharmacodynamic studies and clinical trials in rabbits with congestive heart failure are needed to determine accurate dose and frequency recommendations.

scholarly journals Pharmacokinetic Interaction between Darunavir Boosted with Ritonavir and Omeprazole or Ranitidine in Human Immunodeficiency Virus-Negative Healthy Volunteers

2007 ◽  
Vol 51 (3) ◽  
pp. 958-961 ◽  
Author(s):  
Vanitha J. Sekar ◽  
Eric Lefebvre ◽  
Els De Paepe ◽  
Tine De Marez ◽  
Martine De Pauw ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Plasma Concentration ◽  
Protease Inhibitor ◽  
Healthy Volunteers ◽  
Plasma Concentrations ◽  
Hiv Protease ◽  
Pharmacokinetic Parameters ◽  
Maximum Plasma ◽  
Serious Adverse Events ◽  
Immunodeficiency Virus

ABSTRACT Darunavir (DRV; TMC114; Prezista) is a human immunodeficiency virus (HIV) protease inhibitor used in combination with low-dose ritonavir (RTV) (DRV/r) as a pharmacokinetic enhancer. Protease inhibitor absorption may be decreased during coadministration of drugs that limit stomach acid secretion and increase gastric pH. This study was conducted to investigate the effect of ranitidine and omeprazole on the plasma pharmacokinetics of DRV and RTV in HIV-negative healthy volunteers. Sixteen volunteers completed the study and received DRV/r, DRV/r plus ranitidine, and DRV/r plus omeprazole, in three separate sessions. Treatment was given for 4 days with an additional morning dose on day 5, and regimens were separated by a washout period of 7 days. Samples were taken over a 12-h period on day 5 for the assessment of DRV and RTV plasma concentrations. Pharmacokinetic parameters assessed included DRV area under the curve, maximum plasma concentration, and trough plasma concentration. The least-squares mean ratios and 90% confidence intervals are reported with treatment of DRV/r alone as a reference. Compared with DRV/r alone, no significant changes in DRV pharmacokinetic parameters were observed during coadministration of DRV/r and either ranitidine or omeprazole. Treatment regimens were generally well tolerated, and no serious adverse events were reported. In conclusion, coadministration of DRV/r and ranitidine or omeprazole was well tolerated by the volunteers. Ranitidine and omeprazole did not have a significant influence on DRV pharmacokinetics. No dose adjustments are required when DRV/r is coadministered with omeprazole or ranitidine.

The acute-phase protein response to human immunodeficiency virus infection in human subjects

1999 ◽  
Vol 276 (6) ◽  
pp. E1092-E1098 ◽  
Author(s):  
Farook Jahoor ◽  
Brian Gazzard ◽  
Gary Phillips ◽  
Danny Sharpstone ◽  
Melanie Delrosario ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Virus Infection ◽  
Human Immunodeficiency Virus Infection ◽  
Acute Phase ◽  
Protein Turnover ◽  
Plasma Concentrations ◽  
Retinol Binding Protein ◽  
Whole Body ◽  
Body Protein ◽  
Immunodeficiency Virus

Although several studies have shown that asymptomatic human immunodeficiency virus infection elicits an increase in whole body protein turnover, it is not known whether this increased protein turnover includes changes in the kinetics of acute-phase proteins (APPs). To answer this question, we measured 1) the plasma concentrations of four positive (C-reactive protein, α1-antitrypsin, haptoglobin, and fibrinogen) and four negative APPs [albumin, high-density lipoprotein (HDL)-apolipoprotein (apo) A1, transthyretin, and retinol-binding protein] and 2) the fractional (FSR) and absolute (ASRs) synthesis rates of three positive and three negative APPs using a constant intravenous infusion of [2H5]phenylalanine in five subjects with symptom-free acquired immunodeficiency syndrome (AIDS) and five noninfected control subjects. Compared with the values of the controls, the plasma concentrations, FSRs, and ASRs of most positive APPs were higher in the AIDS group. The negative APPs had faster FSRs in the AIDS group, there was no difference between the ASRs of the two groups, and only HDL-apoA1 had a lower plasma concentration. These results suggest that symptom-free AIDS elicits an APP response that is different from bacterial infections, as the higher concentrations and faster rates of synthesis of the positive APPs are not accompanied by lower concentrations and slower rates of synthesis of most of the negative APPs.

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