Objective: To evaluate the pharmacokinetics (PK) of 25/100 mg carbidopa (CD)/levodopa (LD) compared to half that amount given twice as often using a new, deeply scored, bi-layered tablet.
Background: LD combined with CD has long been the mainstay of Parkinson’s disease (PD) treatment. But with disease progression, patients typically must adjust dose and dose frequency to best manage OFF time and dyskinesias. Current CD/LD formulations fail to provide dosing flexibility. A novel functionally scored tablet was developed to enable precise dosing and improve patient convenience by facilitating easy dose fractionation into four equal 6.25/25 mg CD/LD segments.
Method: Twenty-two healthy adults, aged 35–71 years, were given a whole functionally scored CD/LD 25/100 mg tablet every 4 hours two times. Following a washout period of at least 40 hours, participants received a half-tablet containing CD/LD 12.5/50 mg every 2 hours four times. PK was evaluated every 30 minutes for 12 hours on both study days, along with careful safety monitoring.
Results: Total LD exposure (area under the curve) and time to peak plasma concentration (Tmax) did not differ significantly between subjects given the full dose every 4 hours and those given the half-dose every 2 hours. However, with the more frequent administration of a lower dose, peak LD exposure (Cmax) declined by 44% (p<0.0001), and the difference between Cmax and Cmin diminished by 51% (p<0.0001) in the lower, more frequent dose group. Adverse events, none clinically significant, occurred less frequently (41% vs. 9%) in the lower, more frequent dose group.
Conclusion: More frequent administration of lower doses of CD/LD enabled by a newly designed, deeply scored tablet may improve the stability of circulating LD levels and thus potentially improve tolerability and reduce the risk of motor complications in patients with PD.
This abstract was previously presented at AAN (April 2022).
To cite this abstract in AMA style:
A. Al-Sabbagh, S. Testino, M. Koga, T. Chase, K. Smith. Variability of Plasma Levodopa Conveniently Reduced by More Frequent Administration of Smaller Doses of Carbidopa/Levodopa Using a Novel Functionally Scored Formulation [abstract]. Mov Disord. 2022; 37 (suppl 2). https://www.mdsabstracts.org/abstract/variability-of-plasma-levodopa-conveniently-reduced-by-more-frequent-administration-of-smaller-doses-of-carbidopa-levodopa-using-a-novel-functionally-scored-formulation/. Accessed July 3, 2025.« Back to 2022 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/variability-of-plasma-levodopa-conveniently-reduced-by-more-frequent-administration-of-smaller-doses-of-carbidopa-levodopa-using-a-novel-functionally-scored-formulation/