Comparative Bioavailability Study of a Novel Multi-Day Patch Formulation of Rivastigmine (Twice Weekly) with Exelon® Transdermal Patch (Daily)- A Randomized Clinical Trial.

BACKGROUND

Rivastigmine, a reversible AChEI for symptomatic treatment of mild to moderately severe Alzheimer's dementia, is administered once daily transdermal patches, enabling an easier and continuous drug delivery. A novel multi-day (twice week) patch formulation was developed with greater convenience for patients' therapeutic management.

OBJECTIVE

To assess the bioequivalence under SS conditions of the multiple-day rivastigmine transdermal patch (Test Product, RID-TDS) in comparison to the once-daily Exelon® transdermal patch (Reference Product), both at a release rate of 9.5 mg/24 h.

DESIGN

Single-center, open-label, randomized, multiple-dose study in healthy male adults in a 2- period, 2-sequence-crossover design with multiple applications.

METHODS

Patches were applied on 11 consecutive days for Exelon® and a 4-3-4-day regimen for the multiday test patch (RID-TDS), separated by a 14-day wash-out period. The safety, local tolerability and inhibitory effect of rivastigmine on plasma BuChE activity were also evaluated.

RESULTS

57 subjects completed the study according to the protocol. Calculated point estimates and 90% CI for all primary parameters (AUC96-264, Cmax96-264 and Cmin96-264) were within the predefined acceptance interval of 80.00-125.00%. They were 113.64% (107.33-120.33), 105.14% (98.38- 112.38) and 107.82% (97.78-118.89) respectively. Satisfactory adhesion (CI of mean adhesion above 90%) was demonstrated for RID-TDS but not for Exelon®.

CONCLUSION

Bioequivalence was demonstrated between RID-TDS mg twice a week and Exelon® once daily in SS. Patch adhesion favored RID-TDS despite the longer dosing interval. Both products were well tolerated.