Spray for parkinsonists
The British have developed a nasal spray for the treatment of Parkinson's disease
Anastasia Kuznetsova, N+1
British scientists have developed a nasal spray for the treatment of Parkinson's disease. In it, the drug levodopa is presented in the form of a gel that lingers longer on the epithelium and is better absorbed. This approach makes it possible to increase the concentration of the drug in the brain four times compared to intravenous injection. The study is published in Advanced Science (Wang et al., Enhanced Delivery of Neuroactive Drugs via Nasal Delivery with a Self-Healing Supramolecular Gel).
Parkinson's disease is a neurodegenerative disease in which the structures of the extrapyramidal motor system in the brain are affected: primarily the black substance. In this disease, neurons producing the neurotransmitter dopamine are destroyed. Insufficient dopamine production contributes to the activating effect of the basal ganglia on the cerebral cortex. In patients, this is manifested in an increase in muscle tone, tremor. People become stiff and lose smoothness in their movements. While this disease remains incurable, but with the help of drugs it is possible to alleviate its symptoms.
Levodopa is used for the treatment of Parkinson's disease, as well as dopamine receptor agonists and minoamine oxidase inhibitors. Levodopa (L-DOPA) is a levorotatory isomer of dihydroxyphenylalanine, which is formed in the body and is a precursor of dopamine. Dopamine itself cannot be used for treatment, since it does not penetrate the blood-brain barrier. Levodopa also penetrates into the brain and is metabolized to dopamine. When using the drug in tablets or injections, only a small part of it reaches the central nervous system, and the therapeutic effect is significantly reduced. Nasal sprays have been widely studied in recent years. This dosage form has a significant advantage: through the arterial system of the nose, the drug is quickly absorbed and reaches the brain. For example, sprays have already been developed to treat depression and drug overdose.
British scientists led by David K. Smith from The University of York has created a levodopa drug in the form of a nasal spray. In order for the spray to linger longer in the nasal cavity, it was made on the basis of a hydrogel. To create the gel, glutaminamide and benzaldehyde were used in a ratio of 1:1. The compound in a low concentration is non-toxic to the body. The gel in the bottle is a viscous liquid, but after it is injected into the nose, it quickly forms a gel structure. Such a hydrogel allows the drug to settle better on the epithelium and be absorbed in large quantities than when using tablets.
The researchers studied how the drug is absorbed when delivered to the nose in the form of a gel and in the form of a solution. To do this, they used labeled hydrogen atoms in levodopa, and ten minutes later looked at their distribution in the tissues of experimental mice. When using the gel, the concentration of the substance in the brain averaged 0.49 percent of the administered dose, and when using the solution, this value was at the level of 0.16 percent. The researchers also measured the concentration during intravenous injection, which also turned out to be less than when using a gel (0.12 percent vs. 0.49 percent).
Comparison of the effectiveness of different methods of levodopa administration. A drawing from an article by Wang et al.
Scientists have concluded that levodopa in the form of a gel provides a concentration of the active substance in the brain 4 times more than with intravenous injection. In the future, they plan to optimize the system with additional components to increase the delivery of the drug to the brain, as well as its half-life.
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