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Biodegradable weekly implant delivers stable levodopa levels, aiming to streamline Parkinson’s care while reshaping drug reformulation and delivery strategies.
A novel once-weekly injectable formulation developed by researchers at the University of South Australia (UniSA) introduces a new drug delivery paradigm for Parkinson’s disease and potentially other chronic conditions (1). Designed to administer levodopa and carbidopa over seven days via a biodegradable, subcutaneous in-situ forming implant, this system could reduce pill burden for patients while presenting significant implications across pharmaceutical discovery, development, and manufacturing (2).
“Our goal was to create a formulation that simplifies treatment, improves patient compliance, and maintains consistent therapeutic levels of medication,” said Sanjay Garg, PhD, professor of Pharmaceutical Science at the University of South Australia (1). “This weekly injection could be a game-changer for Parkinson’s care. Levodopa is the gold-standard therapy for Parkinson’s, but its short life span means it must be taken several times a day.”
· In-situ forming biodegradable implants enable sustained levodopa release, requiring novel aseptic processing and polymer-handling techniques.
· Formulation uses FDA-approved PLGA and Eudragit polymers, spotlighting the growing role of excipient science in lifecycle drug innovation.
· Weekly injectable supports 505(b)(2) and EMA hybrid pathways, offering a streamlined regulatory route for reformulated legacy therapeutics.
Although the active ingredients—levodopa and carbidopa—are well-established in Parkinson’s therapy, the innovation lies in the delivery system. This approach reflects a growing emphasis on lifecycle management of existing drugs through formulation science, an area increasingly recognized as critical in modern drug discovery pipelines (3). The use of a pH-responsive polymer blend—PLGA (an FDA-approved biodegradable polymer) and Eudragit L-100—to achieve consistent plasma levels over a full week demonstrates the role of excipient and polymer science in extending the therapeutic impact of legacy molecules (2).
This formulation trend aligns with industry strategies focused on enhancing the therapeutic index and patient adherence of known pharmacophores through novel delivery systems, especially in diseases with long treatment durations and high unmet needs (4).
From a drug development perspective, UniSA’s injectable system offers a reformulation strategy that aligns with patient-centric design principles, increasingly prioritized by regulators and industry sponsors alike (5). Parkinson’s disease currently requires multiple daily doses of oral levodopa/carbidopa to manage motor symptoms due to the drugs’ short plasma half-lives and rapid peripheral metabolism (6). This leads to fluctuations in drug levels and decreased clinical control, a challenge that this once-weekly delivery system aims to address by providing a more stable pharmacokinetic profile (2).
In vitro data from UniSA’s study indicated that more than 90% of levodopa and 81% of carbidopa were released steadily over seven days (1). The biodegradable implant degraded by more than 80% during that period, and cell viability tests showed no significant cytotoxicity (2). These early findings support the potential for human translation.
Importantly, development teams may consider regulatory pathways, such as FDA’s 505(b)(2) route or the European Medicines Agency’s hybrid applications, which allow for the incorporation of published literature and data on approved actives, reducing the burden of full clinical development while still requiring robust evidence of safety and efficacy for the new delivery system (7,8).
The use of in-situ forming injectable implants introduces new challenges and considerations for pharmaceutical manufacturing. UniSA’s system requires formulation techniques that accommodate both the controlled encapsulation of active compounds and the precise modulation of polymer degradation kinetics. Manufacturing such systems typically involves aseptic processing, solvent handling, and quality control of biodegradable polymer blends, all of which differ significantly from those used in oral solid dosage forms (9).
Administering the formulation through a 22-gauge needle also implies the need for tight control over viscosity, injectability, and sterility during scale-up, especially under good manufacturing practice conditions (2). In addition, such polymers as PLGA and pH-sensitive materials like Eudragit may require controlled storage temperatures to maintain stability and prevent premature polymerization or phase separation (10). These requirements may necessitate cold-chain logistics infrastructure or temperature-monitored storage and shipping protocols.
Moreover, the potential for this delivery platform to be customized for release periods ranging from days to weeks presents a modular approach that could appeal to contract development and manufacturing organizations and large-scale manufacturers focused on flexible manufacturing lines for different release profiles and therapeutic indications (2).
UniSA researchers also noted that the injectable platform could be adapted for other chronic conditions requiring sustained drug exposure, including cancer, neurodegenerative diseases, diabetes, chronic pain, and infectious diseases (1). In this context, the platform offers potential for future combination products, in which two or more actives could be delivered together in a single depot, especially relevant in Parkinson’s, for which adjunctive therapies like MAO-B inhibitors or dopamine agonists are frequently prescribed alongside levodopa (6).
Such versatility could support combination regimens that improve therapeutic outcomes and simplify complex dosing schedules, a goal aligned with broader efforts in pharmaceutical development to enhance real-world adherence and reduce polypharmacy burden (11).
The UniSA injectable system for Parkinson’s therapy illustrates how innovative drug delivery mechanisms can drive significant therapeutic and operational advances, even without introducing new molecular entities. For professionals working across the drug development spectrum, this approach exemplifies how novel formulations can improve adherence, reduce dosing frequency, and create new opportunities for market differentiation.
As the researchers move toward human trials, this work may catalyze further investment in long-acting delivery systems that support sustained and controlled drug exposure. Downstream, it may also prompt regulatory and commercial stakeholders to reconsider value frameworks for reformulated legacy therapies with demonstrated real-world impact.
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