Transdermal Delivery of Pramipexole Using Microneedle Technology for the Potential Treatment of Parkinson's Disease

Parkinson's disease (PD) is a debilitating neurodegenerative disease primarily impacting neurons responsible for dopamine production within the brain. Pramipexole (PRA) is a dopamine agonist that is currently available in tablet form. However, individuals with PD commonly encounter difficulties with swallowing and gastrointestinal motility, making oral formulations less preferable. Microneedle (MN) patches represent innovative transdermal drug delivery devices capable of enhancing skin permeability through the creation of microconduits on the surface of the skin. MNs effectively reduce the barrier function of skin and facilitate the permeation of drugs. The work described here focuses on the development of polymeric MN systems designed to enhance the transdermal delivery of PRA. PRA was formulated into both dissolving MNs (DMNs) and directly compressed tablets (DCTs) to be used in conjunction with hydrogel-forming MNs (HFMNs). In vivo investigations using a Sprague-Dawley rat model examined, for the first time, if it was beneficial to prolong the application of DMNs and HFMNs beyond 24 h. Half of the patches in the MN cohorts were left in place for 24 h, whereas the other half remained in place for 5 days. Throughout the entire 5 day study, PRA plasma levels were monitored for all cohorts. This study confirmed the successful delivery of PRA from DMNs (Cmax = 511.00 ± 277.24 ng/mL, Tmax = 4 h) and HFMNs (Cmax = 328.30 ± 98.04 ng/mL, Tmax = 24 h). Notably, both types of MNs achieved sustained PRA plasma levels over a 5 day period. In contrast, following oral administration, PRA remained detectable in plasma for only 48 h, achieving a Cmax of 159.32 ± 113.43 ng/mL at 2 h. The HFMN that remained in place for 5 days demonstrated the most promising performance among all investigated formulations. Although in the early stages of development, the findings reported here offer a hopeful alternative to orally administered PRA. The sustained plasma profile observed here has the potential to reduce the frequency of PRA administration, potentially enhancing patient compliance and ultimately improving their quality of life. This work provides substantial evidence advocating the development of polymeric MN-mediated drug delivery systems to include sustained plasma levels of hydrophilic pharmaceuticals.

Comparative Pharmacokinetics and Bioequivalence Evaluation of Two Formulations of Pramipexole Dihydrochloride Extended-Release Tablets in Healthy Chinese Subjects Under Fasted and Fed States: A Randomized, Open-Label, Single-Dose, Two-Period Crossover Clinical Trial

Background

Pramipexole dihydrochloride extended-release tablet is a novel long-acting form of non-ergot dopamine agonist indicated as one of main therapeutic approaches for Parkinson's disease. However, pharmacokinetic properties of extended-release pramipexole in healthy Chinese subjects remain unclear.

Methods

A single-center, randomized, open-label, two-period crossover, single-dose study was performed to investigate comparative pharmacokinetics and evaluate bioequivalence of 0.375 mg test (Yangtze River Pharmaceutical Group Co., Ltd.) and reference (Trade name: Sifrol®, Boehringer Ingelheim Pharma GmbH & Co. KG) formulations of pramipexole dihydrochloride extended-release tablets in healthy Chinese subjects under fasted and fed states.

Results

A total of 56 subjects (28 in each dietary trial) were enrolled and randomized. After single dose of 0.375 mg test and reference formulations under fasted condition, main pharmacokinetics of pramipexole were as follows: peak concentration (Cmax) were 409.33±95.93 and 413.77±132.03 pg/mL; plasma area under concentration-time curve from time 0 to last measurable concentration (AUC0-t) were 8801.95±1966.83 and 8646.37±2600.49 h*pg/mL; AUC from time 0 to infinity (AUC0-∞) were 9469.03±1991.61 and 9082.95±2666.26 h*pg/mL; elimination half-life (t1/2) were 11.98±3.91 and 9.85±2.63 h; both time to reach Cmax (Tmax) were about 4.50 h, respectively, for test and reference formulations. The 90% confidence intervals of geometric mean ratios (test/reference) of Cmax, AUC0-t and AUC0-∞ under fasted and fed conditions were all within 80-125%. Following administration under fed condition, Cmax and Tmax for both test and reference formulations slightly increased and prolonged to 5.0 h, respectively, but AUC approximately remained unchanged compared with dosing under fasted condition. Test and reference formulations showed similar bioequivalence and favorable safety under fasted and fed states.

Conclusion

Test and reference formulations of pramipexole dihydrochloride extended-release tablets (0.375 mg) showed similar bioequivalence and well safety and tolerability in healthy Chinese subjects under fasted and fed states, which supports further investigations of test formulation in patients with Parkinson's disease.