Weekly Injectable Levodopa-Carbidopa Set to Transform Parkinson’s Care

Researchers at the University of South Australia have developed a groundbreaking weekly injectable formulation of levodopa and carbidopa, designed to significantly enhance the management of Parkinson’s disease. This innovative treatment, which releases medication steadily over a seven-day period, promises to improve adherence for the over eight million individuals globally living with this debilitating condition.

Current management of Parkinson’s symptoms often necessitates frequent dosing, which can be burdensome, particularly for elderly patients or those with swallowing difficulties. The newly introduced injectable could alleviate these challenges, providing a more consistent and effective approach to treatment. The findings were published in the journal Drug Delivery and Translational Research on July 14, 2025.

Innovative Delivery System Improves Patient Compliance

The new formulation combines an FDA-approved biodegradable polymer, PLGA, with Eudragit L-100, a polymer that responds to pH changes. This combination allows for controlled and sustained drug release, with laboratory tests indicating successful delivery of over 90% of the levodopa dose and more than 81% of the carbidopa dose over the course of a week. Importantly, the implant itself demonstrated over 80% degradation within the same timeframe, showing no significant toxicity in cell viability tests.

Lead researcher Professor Sanjay Garg from the Centre for Pharmaceutical Innovation at UniSA emphasized the potential impact of this development. “Our goal was to create a formulation that simplifies treatment, improves patient compliance, and maintains consistent therapeutic levels of medication,” he stated. “This weekly injection could be a significant advancement in Parkinson’s care.”

Potential for Broader Applications

The ease of administration is another significant benefit of this injectable system. Patients can receive the treatment via a fine 22-gauge needle, reducing discomfort and eliminating the need for surgical implantation. As Professor Garg noted, “Reducing the frequency of dosing from multiple times a day to a weekly injection is a major step forward in Parkinson’s therapy. This improvement not only enhances drug delivery but also has the potential to greatly improve patients’ quality of life.”

Moreover, the technology behind this formulation could extend beyond Parkinson’s disease. Professor Garg indicated that it might be adapted for various chronic conditions, including cancer, diabetes, neurodegenerative disorders, and chronic infections. The flexibility of this system allows it to be tuned for drug release over periods ranging from days to weeks, depending on specific therapeutic needs.

UniSA scientists are optimistic about the future of this development, with plans to initiate clinical trials soon, as well as exploring commercial opportunities for the injectable formulation. As research progresses, the implications for both Parkinson’s care and the treatment of other chronic conditions could be profound, potentially reshaping the landscape of long-term drug delivery.