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1996-02-27
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Document 0504
DOCN M9630504
TI Enhanced oral bioavailability of DDI after administration of 6-Cl-ddP,
an adenosine deaminase-activated prodrug, to chronically catheterized
rats.
DT 9603
AU Anderson BD; Morgan ME; Singhal D; Department of Pharmaceutics and
Pharmaceutical Chemistry,; University of Utah, Salt Lake City 84112,
USA.
SO Pharm Res. 1995 Aug;12(8):1126-33. Unique Identifier : AIDSLINE
MED/96021486
AB PURPOSE: 6-Cl-2',3'-dideoxypurine (6-Cl-ddP), an adenosine deaminase
(ADA) activated prodrug of ddI, may be an effective antiretroviral agent
for the treatment of AIDS dementia due to its ability to deliver
increased concentrations of ddI to brain tissue. To examine the
feasibility of administering this drug orally, the oral and hepatic
portal bioavailabilities of 6-Cl-ddP were determined. In addition, the
oral and portal bioavailabilities of ddI after administration of the
prodrug were compared to those from administration of ddI itself.
METHODS: Pharmacokinetic and bioavailability studies were conducted in
fully conscious, chronically catheterized rats in a randomized crossover
design. Plasma ddI and 6-Cl-ddP concentration-time profiles were
determined by HPLC. RESULTS: 6-Cl-ddP has poor apparent oral
bioavailability (7% +/- 3%, n = 3) but high bioavailability after portal
administration (97% +/- 11%), suggesting either poor absorption or
extensive gut wall metabolism. The appearance of > 50% of the dose as
ddI in the systemic circulation after an oral dose of 6-Cl-ddP rules out
poor absorption of the prodrug, and confirms expectations of high ADA
activity in the gastrointestinal tract. Gastric administration of
6-Cl-ddP resulted in a > 10-fold increase in the oral bioavailability of
ddI, from 3-7% to > 50%, and a significant decrease in the variability
in apparent bioavailability. CONCLUSIONS: These data indicate that
lipophilic adenosine deaminase activated prodrugs of dideoxypurine
nucleosides may have limited utility for improving CNS delivery after
oral administration but may be useful in enhancing the oral
bioavailability of highly polar and therefore poorly absorbed
dideoxynucleosides.
DE Adenosine Deaminase/*METABOLISM Administration, Oral Animal Antiviral
Agents/ADMINISTRATION & DOSAGE/BLOOD/*PHARMACOKINETICS Biological
Availability Biotransformation Catheterization Chromatography, High
Pressure Liquid Didanosine/ADMINISTRATION &
DOSAGE/BLOOD/*PHARMACOKINETICS Hepatic Veins Infusions, Intravenous
Male Models, Biological Prodrugs/ADMINISTRATION &
DOSAGE/*PHARMACOKINETICS Purine Nucleosides/ADMINISTRATION &
DOSAGE/BLOOD/ *PHARMACOKINETICS Rats Rats, Sprague-Dawley Support,
U.S. Gov't, P.H.S. JOURNAL ARTICLE
SOURCE: National Library of Medicine. NOTICE: This material may be
protected by Copyright Law (Title 17, U.S.Code).