Single daily pill for Parkinson's disease developed

Materials scientists from Nanyang Technological University, Singapore (NTU Singapore) have developed a new pill which uses the stomach as a drug reservoir and delivers medicines slowly over time to patients with Parkinson’s disease (PD).

Parkinson’s disease is a neurodegenerative disorder which can be treated with levodopa (L-dopa) taken orally. L-dopa is turned into dopamine by the human body — a chemical which is needed by the brain to relay signals needed for muscle control.

Currently, PD patients taking L-dopa may need to take up to six pills (doses) per day, with patients experiencing ‘wearing off’ effects between medications. Some patients also encounter a side effect after a long duration of treatment, in which their limbs jerk or experience involuntary spasms, known as levodopa-induced dyskinesia (LID).

An NTU-incubated start-up is now commercialising a slow-release pill that delivers L-dopa over a period of 24 hours, which could help to alleviate these symptoms. The start-up, called LiberaTx, aims to use the new pill to tackle LID and low drug compliance by patients, in which they fail to take the multiple pills of L-dopa prescribed daily.

LiberaTx founder Associate Professor Joachim Loo, who also led the research, said that encapsulating the drug in a floatable micro-capsule retains it in the stomach for an extended period, and controls its release rate.

“We engineered our micro-capsules to float in the stomach, thereby allowing for a slow but continuous delivery of drugs into the upper intestine for improved absorption,” he said. “This is key in maintaining the drugs’ concentration in the blood, so that dopamine levels in the brain are kept constant over prolonged periods rather than fluctuating, which is the case for current tablets.

“We hope that reducing dosage to just once a day would greatly improve patient compliance, lower the pill burden of these patients, while alleviating the ‘off’ periods that these patients experience. Achieving this would greatly improve quality of life for the patient.”

The FDA-approved materials poly‐L‐lactide (PLLA) and poly (caprolactone) (PCL) are used to make the micro-capsules, which metabolise into carbon dioxide and water in the human body. The micro-capsules are then loaded with PD drugs, which are localised in both the hollow cavity and the shell of the micro-capsules. Being hollow, the micro-particles float on top of the gastric juices in the stomach and stay in the stomach.

Two separate research papers based on animal study results, published in the journals Small and NeuroMolecular Medicine, suggest that the pill could deliver drugs over a 24-hour period. Pharmacokinetics studies of the new micro-encapsulation formulations also show that the new formulations have longer half-lives and mean residence times, with enhanced drug bioavailability, when compared against current L-dopa tablets or formulations used in the clinic.

The LiberaTx team is now in the midst of planning clinical trials to test the pill’s efficacy and has initiated discussions with Professor Louis Tan, Senior Consultant, Neurology and Deputy Director, Research at Singapore’s National Neuroscience Institute (NNI).

“People living with Parkinson’s disease (PD) often need to take levodopa up to six times a day and at set times to prevent the wearing-off effect — a delay of just 30 minutes in taking the next dose can result in a marked increase in their symptoms such as tremor and muscle stiffness,” Prof Tan said.

“This new drug formulation by the NTU team has the potential to enable oral delivery of levodopa in a steady sustained manner over 24 hours that will prolong the effectiveness of levodopa in PD patients experiencing wearing-off effects of levodopa. It may also prevent the development of troublesome long-term motor complications of wearing off and LID when initiated in patients with early PD.”

If proven successful for treatment of PD, the oral micro-capsule may be trialled in patients with other conditions that require multiple drugs daily, such as hypertension, hyperlipidemia and diabetes. The researchers expect the technology platform should not only work with oral drugs currently available on the market, but also with novel chemical compounds that need better oral bioavailability — that is, improving the amount of drug taken orally that reaches its target and so benefits the patient.

Image caption: The timed-release microcapsules can float in the stomach and release drugs over time.

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