title: The relative bioavailability of two marketed controlled release diltiazem dosage forms at steady state in healthy volunteers.
abstract: This study was conducted to determine the relative bioavailability of Dilacor XR capsules compared to Cardizem CD capsules at both low (180 mg d-1) and high (540 mg d-1) dose levels. Trough and serial plasma samples were obtained and pharmacokinetic parameters were calculated from the steady state concentration-time profiles. Mean steady state plasma diltiazem concentrations (AUCss(0-24)) of Dilacor XR were 19% and 26% lower than those of Cardizem CD for the 180 mg d-1 and 540 mg d-1 dose levels, respectively. In addition, Dilacor XR had lower mean Cmax,ss, Tmax,ss, Cmin,ss, and trough values than Cardizem CD with percentage differences ranging from 17% to 29%. The variability (%CV) in the data from the Dilacor XR treatments was higher for each calculated pharmacokinetic parameter compared to the Cardizem CD treatments. The %CV for Dilacor XR ranged from 34% to 104% while the %CV for Cardizem CD ranged from 21% to 49%. From these results, it may be concluded that Dilacor XR is not bioequivalent to Cardizem CD at steady state doses of 180 mg d-1 and 540 mg d-1.
authors.affiliation: Marion Merrell Dow Inc., Kansas City, MO 64134-0627, USA.
authors.forename: C L
authors.initials: CL
authors.lastname: Lippert
authors.forename: T
authors.initials: T
authors.lastname: Arumugham
authors.forename: V O
authors.initials: VO
authors.lastname: Bhargava
authors.forename: M
authors.initials: M
authors.lastname: Eller
authors.forename: S J
authors.initials: SJ
authors.lastname: Weir
mesh_terms: D000328:Adult; D001682:Biological Availability; D002121:Calcium Channel Blockers / Q000008:administration & dosage* / Q000097:blood / Q000493:pharmacokinetics*; D002626:Chemistry, Pharmaceutical; D018592:Cross-Over Studies; D003692:Delayed-Action Preparations; D004110:Diltiazem / Q000008:administration & dosage* / Q000097:blood / Q000493:pharmacokinetics*; D004305:Dose-Response Relationship, Drug; D006207:Half-Life; D006801:Humans; D008297:Male; D008875:Middle Aged
chemical_list: D002121:Calcium Channel Blockers; D003692:Delayed-Action Preparations; D004110:Diltiazem