Pharmacokinetic characteristics of fentanyl iontophoretic trandermal system over a range of applied current.

ABSTRACT

OBJECTIVE: To evaluate the pharmacokinetic (PK) characteristics of a modified fentanyl iontophoretic transdermal system (ITS). RESEARCH DESIGN AND METHODS: This was a prospective, open-label, single-center, randomized, 3-period, 5-treatment, 6-sequence study. Each subject was randomly assigned to receive three treatments in a sequence consisting of intravenous fentanyl citrate, fentanyl ITS at 170 µA, and then one of three other fentanyl ITS treatments at 140, 200 or 230 µA. MAIN OUTCOME MEASURES: The following PK parameters were determined Cmax, tmax, t1/2, AUC23 - 25 and amount of fentanyl absorbed into systemic circulation (i.e., Dose Absorbed). RESULTS: Fifty-two subjects received at least one fentanyl treatment. Serum exposure (Cmax and AUC23 - 25) and Dose Absorbed increased with increasing current. The median tmax ranged from 23.0 to 23.2 h across the 4 ITS groups. Mean t1/2 values ranged from 11.0 to 13.0 h. The Dose Absorbed from the fentanyl ITS at 170 µA met bioequivalence criteria when compared to data from an earlier version of the fentanyl ITS. CONCLUSIONS: Exposure of fentanyl and the amount of fentanyl absorbed increased with the magnitude of applied current with the ITS. The fentanyl ITS at 170 µA is bioequivalent to an earlier version of the system.