A new weekly injection developed by University of South Australia scientists could change Parkinson’s treatment by replacing the need for multiple daily pills – potentially helping millions of patients worldwide.
Scientists at the University of South Australia (UniSA) have developed a biodegradable, once-weekly injectable formulation that steadily delivers two cornerstone Parkinson’s drugs – levodopa and carbidopa – over the course of seven days.
The formulation – described in the journal Drug Delivery and Translational Research – is injected under the skin or into muscle tissue, where it gradually releases the medication.
“Our goal was to create a formulation that simplifies treatment, improves patient compliance, and maintains consistent therapeutic levels of medication. This weekly injection could be a game-changer for Parkinson’s care,” said Professor Sanjay Garg, lead researcher from UniSA’s Centre for Pharmaceutical Innovation.
Addressing a major treatment burden
Parkinson’s disease is the second most common neurological disorder, characterised by tremors, stiffness and slowed movement. Currently, patients often take oral medication multiple times per day – which can be especially challenging for elderly people or those with swallowing difficulties.
This frequent dosing not only burdens patients but can lead to inconsistent drug levels, side effects and reduced therapeutic benefit.
“Levodopa is the gold-standard therapy for Parkinson’s, but its short life span means it must be taken several times a day,” Garg explained.
Innovative drug delivery system
UniSA PhD student Deepa Nakmode was instrumental in developing the long-acting injectable – which she describes as an in-situ forming implant. The injectable uses FDA-approved biodegradable polymer PLGA combined with Eudragit L-100 – a pH-sensitive polymer – to ensure a controlled and sustained release of both drugs.
“After years of focused research, it’s incredibly rewarding to see our innovation in long acting injectables for Parkinson’s disease reach this stage. Our invention has now been filed for an Australian patent,” Nakmode said.
Key lab findings include:
- Over 90 percent of the levodopa dose and more than 81 percent of the carbidopa dose were released over seven days.
- The implant degraded by over 80 percent within a week.
- No significant toxicity was observed in cell viability tests.
- The formulation can be administered via a fine 22-gauge needle, avoiding surgical implantation.
Broader implications beyond Parkinson’s
Professor Garg says this injectable platform could have wider applications for other chronic diseases, including cancer, diabetes, neurodegenerative disorders and infections that require sustained drug administration.
“By reducing the frequency of dosing from multiple times a day to a weekly injection is a major step forward in Parkinson’s therapy. We’re not just improving how the drug is delivered; we’re improving patients’ lives,” he said.
What’s next?
With patent filing complete, the research team is now preparing for clinical trials and exploring commercialisation opportunities. The technology’s flexibility also means it could be tuned to release drugs over several days or weeks – depending on the treatment needs. As they optimise the formulation for different dosing schedules, this long-acting injectable could significantly improve treatment for Parkinson’s and other chronic conditions that require consistent medication delivery.