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Multiple dose pharmacokinetics of a new once daily extended release tolterodine formulation versus immediate release tolterodine.

Abstract：

OBJECTIVE:To determine the multiple dose pharmacokinetics of a new extended release (ER) capsule formulation of tolterodine, compared with the existing immediate release (IR) tablet, in healthy volunteers. DESIGN:Nonblind, randomised, 2-way crossover trial. PARTICIPANTS:19 healthy volunteers (7 females, 12 males), mean age 33 years (range 18 to 55 years). Prior to the study, all volunteers were classified as either extensive or poor metabolisers by cytochrome P450 2D6 genotyping. METHODS:Volunteers received tolterodine ER 4mg once daily or tolterodine IR 2mg twice daily for 6 days (all doses given as the L-tartrate salt). A washout period of 7 days separated the 2 treatments. Serum concentrations of tolterodine, its active 5-hydroxymethyl metabolite (5-HM) and the active moiety (extensive metabolisers: sum of unbound tolterodine + 5-HM; poor metabolisers: unbound tolterodine) were measured for up to 48 hours post-dose on day 6 (steady state). Tolerability was also determined. RESULTS:17 volunteers (13 extensive metabolisers, 4 poor metabolisers) completed the study and were evaluable for both treatment periods. The 90% confidence interval for the geometric mean ratio of area under the serum concentration-time curve to 24 hours (AUC24) of the active moiety, for all volunteers combined, indicated equivalence for the 2 formulations. Pooled analysis also demonstrated that the peak serum concentration (Cmax) of the active moiety following administration of tolterodine ER was around 75% of that observed for the IR tablet, whereas the trough concentration was around 1.5-fold higher. Overall, the pharmacokinetics of tolterodine (irrespective of genotype) and 5-HM (extensive metabolisers only) were consistent with sustained drug release over 24 hours. Tolterodine ER was well tolerated. CONCLUSIONS:The new once daily ER formulation of tolterodine 4mg shows pharmacokinetic equivalence (AUC24) to the existing IR tablet given at a dose of 2mg twice daily. Findings of lower Cmax for tolterodine ER may explain the significantly lower rate of dry mouth subsequently observed in patients with overactive bladder.

journal_name

Clin Pharmacokinet

journal_title

Clinical pharmacokinetics

authors

Olsson B,Szamosi J

doi

10.2165/00003088-200140030-00006

keywords:

subject

Has Abstract

pub_date

2001-01-01 00:00:00

pages

227-35

issue

eissn

0312-5963

issn

1179-1926

journal_volume

pub_type

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Multiple dose pharmacokinetics of a new once daily extended release tolterodine formulation versus immediate release tolterodine.