Abstract:
:The anti-hepatitis C virus nucleotide prodrug GS-6620 employs a double-prodrug approach, with l-alanine-isopropyl ester and phenol moieties attached to the 5'-phosphate that release the nucleoside monophosphate in hepatocytes and a 3'-isobutyryl ester added to improve permeability and oral bioavailability. Consistent with the stability found in intestinal homogenates, following oral administration, intact prodrug levels in blood plasma were the highest in dogs, followed by monkeys, and then were the lowest in hamsters. In contrast, liver levels of the triphosphate metabolite at the equivalent surface area-adjusted doses were highest in hamsters, followed by in dogs and monkeys. Studies in isolated primary hepatocytes suggest that relatively poor oral absorption in hamsters and monkeys was compensated for by relatively efficient hepatocyte activation. As intestinal absorption was found to be critical to the effectiveness of GS-6620 in nonclinical species, stomach pH, formulation, and food effect studies were completed in dogs. Consistent with in vitro absorption studies in Caco-2 cells, the absorption of GS-6620 was found to be complex and highly dependent on concentration. Higher rates of metabolism were observed at lower concentrations that were unable to saturate intestinal efflux transporters. In first-in-human clinical trials, the oral administration of GS-6620 resulted in poor plasma exposure relative to that observed in dogs and in large pharmacokinetic and pharmacodynamic variabilities. While a double-prodrug approach, including a 3'-isobutyryl ester, provided higher intrinsic intestinal permeability, this substitution appeared to be a metabolic liability, resulting in extensive intestinal metabolism and relatively poor oral absorption in humans.
journal_name
Antimicrob Agents Chemotherjournal_title
Antimicrobial agents and chemotherapyauthors
Murakami E,Wang T,Babusis D,Lepist EI,Sauer D,Park Y,Vela JE,Shih R,Birkus G,Stefanidis D,Kim CU,Cho A,Ray ASdoi
10.1128/AAC.02350-13subject
Has Abstractpub_date
2014-01-01 00:00:00pages
1943-51issue
4eissn
0066-4804issn
1098-6596pii
AAC.02350-13journal_volume
58pub_type
杂志文章abstract::The safety, tolerance, and pharmacokinetics of amphotericin B lipid complex (ABLC) were studied in a cohort of pediatric cancer patients. Six children with hepatosplenic candidiasis (HSC) received 2.5 mg of ABLC/kg of body weight/day for 6 weeks for a total dosage of 105 mg/kg. Mean serum creatinine (0.85 +/- 0.12 mg/...
journal_title:Antimicrobial agents and chemotherapy
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abstract::Lethal mutagenesis is an antiviral approach that consists in extinguishing a virus by an excess of mutations acquired during replication in the presence of a mutagenic agent, often a nucleotide analogue. One of its advantages is its broad spectrum nature that renders the strategy potentially effective against emergent...
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journal_title:Antimicrobial agents and chemotherapy
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journal_title:Antimicrobial agents and chemotherapy
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journal_title:Antimicrobial agents and chemotherapy
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journal_title:Antimicrobial agents and chemotherapy
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abstract::The potent antiretroviral pyrimidinediones IQP-0528 (PYD1) and IQP-0532 (PYD2) were formulated in polyurethane intravaginal rings (IVRs) as prophylactic drug delivery systems to prevent the sexual transmission of HIV-1. To aid in the selection of a pyrimidinedione candidate and the optimal loading of the drug in the I...
journal_title:Antimicrobial agents and chemotherapy
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doi:10.1128/AAC.05721-11
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journal_title:Antimicrobial agents and chemotherapy
pub_type: 杂志文章,多中心研究
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更新日期:1996-12-01 00:00:00
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journal_title:Antimicrobial agents and chemotherapy
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doi:10.1128/aac.48.1.130-136.2004
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journal_title:Antimicrobial agents and chemotherapy
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journal_title:Antimicrobial agents and chemotherapy
pub_type: 杂志文章
doi:10.1128/AAC.02799-13
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abstract::9-R-[2-(Phosphonomethoxy)propyl]-adenine (tenofovir) is an acyclic nucleoside phosphonate with antiviral activity against human immunodeficiency virus type 1 (HIV-1) and hepatitis B virus (HBV). Tenofovir is not orally bioavailable but becomes orally active against HIV-1 infection as the disoproxil ester (tenofovir di...
journal_title:Antimicrobial agents and chemotherapy
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journal_title:Antimicrobial agents and chemotherapy
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journal_title:Antimicrobial agents and chemotherapy
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journal_title:Antimicrobial agents and chemotherapy
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journal_title:Antimicrobial agents and chemotherapy
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journal_title:Antimicrobial agents and chemotherapy
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journal_title:Antimicrobial agents and chemotherapy
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