title: Single-dose pharmacokinetics of enteric-coated didanosine in HIV-infected children.
abstract: Didanosine remains a cornerstone nucleoside analogue for the treatment of HIV infection. A potential problem with the buffered formulations of didanosine is the likelihood of interactions with other drugs that require an acidic pH for absorption or can be chelated by cations in the buffer. An encapsulated enteric-coated (EC) bead formulation of didanosine has been approved and is routinely used as an alternative to the chewable/dispersible buffered tablet formulation. The objective of this study was to evaluate the single-dose pharmacokinetics of didanosine EC at 240 mg/m2 in 10 HIV-infected children. Didanosine EC was administered at time 0 on an empty stomach with no other concomitant medications. Blood samples were collected at pre-dose, 0.5, 1, 2, 4, 8 and 12 h post-dose. Didanosine was measured in plasma using radioimmunoassay. Ten subjects completed the intensive pharmacokinetic evaluation; data are available for eight participants. Plasma concentrations of didanosine following EC administration were analysed using non-compartmental methods. Median (range) AUCinfinity, Cmax, Tmax and CL/F for didanosine following EC administration were 2385 (1291, 3966) ng x h/ml, 854 (300, 1799) ng/ml, 3.0 (1.0, 8.1) h and 3.3 (2.7-6.4) l/h/kg, respectively. Results from this study indicate that the didanosine Cmax is decreased and Tmax is prolonged, but total exposure of didanosine in plasma following didanosine EC administration appears similar to previous data collected in HIV-infected children following buffered didanosine administration.
authors.affiliation: The University of Alabama at Birmingham, Birmingham, Ala., USA.
authors.forename: Jennifer R
authors.initials: JR
authors.lastname: King
authors.forename: Sharon
authors.initials: S
authors.lastname: Nachman
authors.forename: Ram
authors.initials: R
authors.lastname: Yogev
authors.forename: Janice
authors.initials: J
authors.lastname: Hodge
authors.forename: Grace
authors.initials: G
authors.lastname: Aldrovandi
authors.forename: Bharat
authors.initials: B
authors.lastname: Damle
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Smith
authors.forename: Andrew
authors.initials: A
authors.lastname: Wiznia
authors.forename: Edward P
authors.initials: EP
authors.lastname: Acosta
mesh_terms: D019380:Anti-HIV Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics; D019540:Area Under Curve; D002626:Chemistry, Pharmaceutical; D002648:Child; D002675:Child, Preschool; D016049:Didanosine / Q000008:administration & dosage* / Q000493:pharmacokinetics; D005260:Female; D015658:HIV Infections / Q000188:drug therapy*; D006801:Humans; D008297:Male; D013608:Tablets, Enteric-Coated
chemical_list: D019380:Anti-HIV Agents; D013608:Tablets, Enteric-Coated; D016049:Didanosine