(54) Methods for dopamine delivery across the blood-brain barrier in treating Parkinson’s disease: a systematic literature review

Background: : Parkinson’s disease (PD) is a neurodegenerative disorder caused by the loss of dopamine-producing neurons in the substantia nigra, leading to motor impairments such as bradykinesia, tremors, and postural instability. The main treatment, levodopa (L-DOPA), temporarily restores dopamine in the brain but does not slow disease progression and can cause dyskinesias–irregular, involuntary movements–if taken for an extended duration. Over 10 million people worldwide live with PD, many needing ongoing treatment as symptoms progress. To improve outcomes, new delivery methods are being researched, including PEGylated lipid-based carriers and nanoparticle technology that can enhance dopamine delivery across the blood-brain barrier.

Objective: : To compare the efficacy of L-DOPA, PEGylated lipid-based carriers, and nanoparticles in improving outcomes for early-stage Parkinson’s disease.

Methods: : Peer-reviewed journal articles were sourced using databases such as Springer Nature, Science Direct, and ACS Publications. Sources were narrowed using the keywords “Parkinson’s,” “L-DOPA,” “liposome,” and “nanoparticle” in a range of thirty-five years (1990-2025). Articles that compared at least two of the treatment options or discussed a combination were prioritized. Sources were evaluated based on the quality of their statistical analysis and the consistency of results demonstrated among clinical trials. The advantages and limitations of each treatment option were identified through comparative analysis of the articles.

Results: : Through close examination, 9 articles were narrowed down for further comparison. They pertained to a specific treatment option (L-DOPA, lipid-carrier, and nanoparticle), with 3 articles for each of these focus areas. Three articles supported L-DOPA coupling with other treatments such as nanoparticle technology to optimize patient results. Three articles focused on lipid-based carriers as more effective than L-DOPA to treat PD and minimize side effects.

Conclusions: : Systematic research suggests that liposome-based delivery and levodopa-nanoparticle combinations offer a more efficient approach to restoring dopamine levels in PD. Coupling levodopa with nanoparticles appears especially promising as it improves drug delivery while minimizing side effects. Emerging nanotechnology aims to reduce oxidative stress and protect dopaminergic neurons, highlighting potential pathways for more comprehensive non-dopamine focused therapies for patients with PD. Continued research is needed to evaluate long-term safety and the most effective treatments for Parkinson’s disease.

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