Nasal spray gel directly delivers Parkinson's drugs to the brain
Getting drugs into the brain is no easy feat, but the nose is emerging as one of the most direct routes. Now, researchers in the UK have developed a hydrogel that can be administered as a nasal spray, lining the tissue and delivering a common Parkinson’s drug straight to the brain.
Parkinson’s disease is characterized by a deficiency of dopamine in the brain, so the most common treatment involves reducing the symptoms with drugs that boost dopamine levels. Levodopa, or L-DOPA, is one of the most commonly used of these, but when taken orally relatively low amounts of the drug actually make it to the brain. This is because much of it gets metabolized in the liver first, or filtered out by the blood-brain barrier.
Past studies have shown that drugs delivered through the nose can bypass these checkpoints on their way to the brain, with experimental nasal sprays in development for conditions such as depression, heroin overdoses or even peanut allergies. And now, researchers from York University and King’s College London have added Parkinson’s to the list.
The team developed a levodopa nasal spray that allowed the drug to pass into the fine blood vessels in the nasal cavity, where it’s fast-tracked to the brain. Since a liquid mist wouldn’t linger long enough for much of the drug to soak in, the researchers embedded levodopa into a hydrogel that coats the tissue.
“The results indicated that the gel gave the drug better adhesion inside the nose, which allowed for better levels of uptake into both the blood and brain,” says David Smith, corresponding author of the study.
The researchers tested the technique in mice, using nasal sprays of either liquid or hydrogel, as well as intravenous injections of the drug. And sure enough, they found that nasal hydrogel delivery was the most effective.
“Not only did the gel perform better than a simple solution, but the brain uptake was better than that achieved using intravenous injection of the drug,” says Khuloud Al-Jamal, corresponding author of the study. “This suggests that nasal delivery of Parkinson’s drugs using this type of gel may have clinical relevance.”
The team says that nasal hydrogels could allow for smaller doses of levodopa to be used, which is important because the drug is associated with side effects such as involuntary movements and drug resistance.
The research was published in the journal Advanced Science.
Source: York University