Willi Cawello

Steady-state plasma concentration profile of transdermal rotigotine: an integrated analysis of three, open-label, randomized, phase I multiple dose studies.

BACKGROUND The dopamine agonist rotigotine is formulated in a transdermal delivery system (patch) for once-daily application. It has been reported as efficacious in the treatment of idiopathic Parkinsons disease (PD) and restless legs syndrome. OBJECTIVE This article summarizes the results of 3 clinical studies conducted to characterize the 24-hour pharmacokinetic profile of rotigotine in steady state and the effect of different patch application sites on this profile. In addition, the relative bioavailability of a single, large patch versus 2 smaller patches was assessed. METHODS One Phase I study (SP871) assessed the steady-state pharmacokinetic properties at different application sites at a rotigotine maintenance dose of 3 mg/24 hours in healthy participants. Due to tolerability issues, the steady-state pharmacokinetic properties of rotigotine at higher doses (8 mg/24 hours) was assessed in 2 Phase I studies (SP630, SP651) in early-stage PD patients. Relative rotigotine bioavailability from a 40 cm(2) patch versus 2 × 20 cm(2) patches (SP651) and from a 15 cm(2) patch versus 1 × 5 cm(2) + 1 × 10 cm(2) patches (SP871) was also evaluated. Rotigotine concentrations in plasma were analyzed using a validated LC-MS/MS method. The pharmacokinetic variables were calculated using standard noncompartmental analysis. RESULTS Release of rotigotine to the skin was 31% to 62% of total drug content in the patch. Variability of rotigotine exposure was low within participants (15%) compared with the variability observed between participants (54%). Rotigotine exposure increased proportionally in the therapeutic dose range of 2 mg/24 hours to 8 mg/24 hours. Plasma concentrations at steady state were stable over the 24-hour patch-on period. Delivery via a single, large patch compared with a combination of smaller patches did not appear to influence exposure to rotigotine. Bioavailability showed some variability depending on patch application site (hip, shoulder, abdomen, flank, thigh, upper arm); the respective mean ratios for AUC ranged between 0.87 (abdomen vs flank) and 1.46 (shoulder vs thigh). CONCLUSIONS Continuous rotigotine delivery via a once-daily transdermal patch generated stable mean steady-state 24-hour plasma concentrations in healthy participants as well as patients with early-stage PD. Doses were achieved either by application of 1 large patch or a combination of smaller patches, resulting in the same total surface area.

No Pharmacokinetic Interaction Between Lacosamide and Carbamazepine in Healthy Volunteers

Lacosamide is a new antiepileptic drug for adjunctive treatment of adult partial‐onset seizures. Two open‐label, multiple‐dose clinical trials were conducted to evaluate the potential for pharmacokinetic interaction between lacosamide and carbamazepine. The influence of carbamazepine on lacosamide pharmacokinetics (trial A) and lacosamide on carbamazepine pharmacokinetics (trial B) was investigated in 19 (trial A) and 18 (trial B) healthy male participants. Trial A participants received lacosamide 200 mg bid alone and with carbamazepine 200 mg bid. Trial B participants received carbamazepine 200 mg bid alone and with lacosamide 200 mg bid. Pharmacokinetic parameters, area under the concentration‐time curve during a dosage interval at steady state (AUCτ,ss), and maximum steady‐state plasma drug concentration during a dosage interval (Cmax,ss) of lacosamide, carbamazepine, and carbamazepine‐10,11‐epoxide were measured and compared for each drug alone and together. The AUCτ,ss and Cmax,ss point estimates (combined vs sole treatment) showed relative bioavailability of approximately 100% for both drugs. All 90% confidence intervals of AUCτ,ss and Cmax,ss were within the generally accepted bioequivalence ranges of 80% to 125%. No changes in rate or extent of absorption or terminal half‐life were observed. These results suggest that lacosamide and carbamazepine have a low potential for pharmacokinetic drug‐drug interaction in clinical use.

Metabolism and pharmacokinetics of prostaglandin E1 administered by intravenous infusion in human subjects

In a single-blind, randomized, two-way crossover study with 12 healthy male volunteers, 60 μg of prostaglandin E1 (PGE1) or placebo was administered by intravenous infusion during a 120-min period. PGE1, 13,14-dihydro-PGE1 (PGE0) and 15-keto-PGE0 plasma concentrations were measured by a highly specific and sensitive GC-MS/MS method.Endogenous PGE1 plasma concentrations ranged between 1.2 and 1.8 pg·ml−1. Endogenous PGE0 and 15-keto-PGE0 plasma concentrations varied from 0.8 to 1.3 pg·ml−1 and from 4.2 to 6.0 pg/ml respectively. During intravenous infusion of PGE1, plasma PGE1 concentrations rose to a level twice as high as during the placebo infusion. In contrast, PGE0 plasma concentrations were 8 times higher during PGE1 infusion than during placebo infusion, and 15-keto-PGE0 plasma concentrations were 20 times higher.The new analytical method has thus been useful to describe the pharmacokinetics of PGE1 and its metabolites PGE0 and 15-keto-PGE0, during and after intravenous infusion of PGE1.

Absorption, Disposition, Metabolic Fate, and Elimination of the Dopamine Agonist Rotigotine in Man: Administration by Intravenous Infusion or Transdermal Delivery

The dopamine agonist rotigotine was developed for the treatment of Parkinsons disease and restless legs syndrome. Disposition, metabolism, elimination, and absolute bioavailability of rotigotine were determined in six healthy male subjects by using two different forms of administration in a randomized sequence with a crossover design. Treatment A (continuous infusion) consisted of a single radiolabeled 12-h intravenous infusion of 1.2 mg of rotigotine (0.6 mg of [14C] and 0.6 mg of unlabeled rotigotine, 3.7 MBq) solution. Treatment B (transdermal application) consisted of a single 10-cm2 patch containing 4.5 mg of unlabeled rotigotine with a patch-on period of 24 h. During the 12 h-infusion, total radioactivity concentration rapidly increased within 2 h; there was a slight additional increase toward the end of infusion. Plasma concentrations of total radioactivity declined by 75% within 12 h after completion of infusion. More than 94% of the radioactivity was excreted 216 h after the start of infusion, 71% by the kidneys and 23% by feces. Renal elimination of the parent compound was <1%. Systemically absorbed rotigotine was rapidly metabolized. The major rotigotine biotransformation pathway was conjugation of the parent compound, mainly by sulfation; a second pathway was the formation of phase 1 metabolites (N-desalkylation) with subsequent conjugation. Plasma concentration-time profiles of unchanged rotigotine during and after infusion and during and after patch administration were comparable. Absolute bioavailability of transdermally applied rotigotine was 37%.

Transdermal administration of radiolabelled [14C]rotigotine by a patch formulation: A mass balance trial

Background and objectiveThe dopamine agonist rotigotine has been formulated in a silicone-based transdermal system for once-daily administration. The objective of the present study was to characterise the mass balance of rotigotine in humans after administration of a single transdermal patch containing radiolabelled [14C]rotigotine and to quantify the pharmacokinetic profiles of total radioactivity and the corresponding rotigotine plasma concentrations.MethodsIn a phase I trial, six healthy male Caucasian subjects were administered a single 10 cm2 patch containing 4.485mg of unlabelled and 0.015mg of [14C]-labelled rotigotine (total radioactivity 0.09 MBq per patch) with a patch-on period of 24 hours. Radioactivity was determined by liquid scintillation counting in unused patches, used patches, skin wash samples after 24 hours, plasma, urine and faeces samples up to 96 hours and skin stripping samples at 96 hours postapplication. Unconjugated rotigotine in plasma samples was determined by liquid chromatography with tandem mass spectrometry. Plasma samples were taken predose and 2, 4, 6, 8, 12, 24, 48, 72 and 96 hours after patch application.ResultsThe rotigotine transdermal patch was well tolerated, and all subjects completed the trial. A total of 94.6% of the administered dose was recovered within 96 hours after patch application inclusive of the residual amounts in the patch. Within 24 hours, 51% of the total radioactivity was delivered to the human body system and 46.1% was systemically absorbed. Total radioactivity recovered in urine and faeces was 30.4% and 10.2%, respectively, of the radioactivity applied (corresponding to 65.8% and 21.8% of the dose absorbed, respectively).ConclusionsThe mass balance of rotigotine within 96 hours after transdermal delivery of rotigotine via a 10 cm2 [14C]rotigotine patch with a total drug content of 4.5mg (corresponding to the nominal dose of 2mg/24 hours for the marketed rotigotine transdermal system) has been 95% explained. The systemic absorption was 46.1% of the administered dose, the majority of which was cleared from the body via urine and faeces within 96 hours after patch application.

Pharmacodynamic and pharmacokinetic evaluation of coadministration of lacosamide and an oral contraceptive (levonorgestrel plus ethinylestradiol) in healthy female volunteers

To determine whether the antiepileptic drug lacosamide affects the pharmacokinetics or pharmacodynamics of a combined oral contraceptive (OC; ethinylestradiol 0.03 mg plus levonorgestrel 0.15 mg).

Tolerability, pharmacokinetics, and bioequivalence of the tablet and syrup formulations of lacosamide in plasma, saliva, and urine: Saliva as a surrogate of pharmacokinetics in the central compartment

Purpose:  To test for bioequivalence of 200 mg lacosamide oral tablet and syrup formulations. Additional objectives were to compare the pharmacokinetic profile of lacosamide in saliva and plasma, and to evaluate its tolerability.

Influence of domperidone on pharmacokinetics, safety and tolerability of the dopamine agonist rotigotine

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT Rotigotine transdermal patch is a new non-ergolinic dopamine agonist developed for the treatment of Parkinsons disease and restless legs syndrome. Peripheral dopaminergic side-effects of dopamine agonists such as nausea and vomiting can be prevented by the antiemetic agent domperidone. WHAT THIS STUDY ADDS The study results show no evidence for an interaction of domperidone on bioavailability and steady-state pharmacokinetics of transdermal rotigotine. Co-administration of domperidone and rotigotine does not require dose adjustments for rotigotine transdermal patch. AIMS To evaluate the influence of the antiemetic agent domperidone on steady-state pharmacokinetics, safety and tolerability of multiple-dose treatment of the transdermally applied non-ergolinic dopamine agonist rotigotine. METHODS Sixteen healthy male subjects (mean age 30.3 years) participated in a randomized, two-way crossover clinical trial. Treatment A consisted of transdermal rotigotine patch (2 mg (24 h)(-1), 10 cm(2), total drug content 4.5 mg) applied daily for 4 days, and concomitant oral domperidone (10 mg t.i.d.) for 5 days. For treatment B, subjects received only transdermal rotigotine treatment (daily for 4 days). Pharmacokinetic variables describing systemic exposure and renal elimination of rotigotine and metabolites, and safety and tolerability of the treatment were assessed. RESULTS The primary steady-state pharmacokinetic parameters (C(max,ss) and AUC((0-24),ss)) were similar with or without co-administration of domperidone. Geometric mean ratios were close to 1 and respective 90% confidence intervals were within the acceptance range of bioequivalence (0.8, 1.25): C(max,ss) 0.96 (0.86, 1.08) and AUC((0-24),ss) 0.97 (0.87, 1.08). t(max,ss), t(1/2), secondary parameters calculated on days 4/5 after repeated patch application (C(min,ss), C(ave,ss), AUC((0-tz))) and renal elimination for unconjugated rotigotine and its metabolites were also similar with and without comedication of domperidone. A reduction in the dopaminergic side-effect nausea was seen with domperidone comedication. CONCLUSIONS No changes of pharmacokinetic parameters describing systemic exposure and renal elimination of rotigotine were observed when domperidone was administered concomitantly with rotigotine. The lack of pharmacokinetic interactions indicates that a dose adjustment of rotigotine transdermal patch is not necessary with concomitant use of domperidone.

No Pharmacokinetic Interaction Between Lacosamide and Valproic Acid in Healthy Volunteers

Two open‐label, randomized, multiple‐dose clinical studies evaluated the potential for pharmacokinetic interaction between the antiepileptic drugs lacosamide and valproic acid. The influence of lacosamide on valproic acid pharmacokinetics (trial A) and valproic acid on lacosamide pharmacokinetics (trial B) was investigated in 32 healthy male volunteers, 16 in each trial. Volunteers in trial A received valproic acid (300 mg bid) with randomization to either early or late addition of lacosamide (200 mg bid). Those in trial B received lacosamide (200 mg bid) with randomization to either early or late addition of valproic acid (300 mg bid). Area under the concentration‐time curve during a 12‐hour dosing interval at steady state (AUCTSS) and maximum steady‐state plasma drug concentration (Cmax, ss) were measured for each drug alone and together and tested for equivalence. The point estimates (90% confidence intervals) for AUCt, ss and Cmax, ss were 104% (99%–109%) and 101% (97%–107%), respectively, for valproic acid and 100% (98%–103%) and 101% (96%–107%), respectively, for lacosamide, which were within the generally accepted equivalence range of 80% to 125%. No changes in the rate or extent of absorption, terminal half‐life, or time to maximum concentration were observed. These results suggest that lacosamide and valproic acid have no relevant pharmacokinetic drug‐drug interaction.

Single dose pharmacokinetics of the transdermal rotigotine patch in patients with impaired renal function

AIM To evaluate the influence of different stages of chronic renal insufficiency on the pharmacokinetics and safety/tolerability of the transdermally applied dopamine agonist rotigotine in an open label group comparison including 32 subjects (healthy, mild, moderate or severe impairment of renal function and patients with end-stage renal insufficiency requiring haemodialysis). METHODS All subjects received a single transdermal 10 cm² patch (24 h patch-on period) containing 4.5 mg rotigotine (nominal drug release 2 mg 24 h⁻¹). Main evaluations included relative bioavailability and renal elimination of rotigotine and its metabolites. RESULTS Point estimates for the ratios between the groups with moderate to severe renal impairment and healthy subjects for the pharmacokinetic parameters AUC(0,t(last) ) and C(max) for the active substance unconjugated rotigotine were near 1:0.88 for AUC and 0.93 for C(max) for moderate renal impairment, 1.14 and 1.18 for severe renal impairment and 1.05 and 1.25 for end-stage renal insufficiency requiring haemodialysis. There was no correlation of these parameters with creatinine clearance. The amount of unconjugated rotigotine excreted into urine and renal clearance decreased with increasing severity of renal insufficiency but had no observable effect on total clearance as the amounts excreted were below 1% of the administered dose. Occurrence of adverse events did not increase with the degree of renal insufficiency. CONCLUSIONS The pharmacokinetic profiles of unconjugated rotigotine were similar in healthy subjects and subjects with impaired renal function indicating that no dose adjustments are required for transdermal rotigotine in patients with different stages of chronic renal insufficiency including patients on haemodialysis.