1. A pharmaceutically acceptable liquid composition for treating a neurological disorder in combination therapy with levodopa, comprising arginine and a therapeutically effective amount of carbidopa, said composition comprising from about 1% to about 6% wt. carbidopa, has a pH of from about 8.0 to about 9.5 at 25 ° C and is substantially stable at 25 ° C for 48 hours or more, and said neurological disorder is selected from restless legs syndrome, Parkinson’s disease, secondary parkinsonism, Huntington's disease (Huntington), parkinson-like syndrome, progressive supranuclear palsy (PSP), multiple systemic atrophy (MSA) or amyotrophic lateral sclerosis (ALS) .2. A pharmaceutically acceptable liquid composition according to claim 1, characterized in that the molar ratio of carbidopa: arginine in it is selected from 1: 1 to 1: 2.5.3. The pharmaceutically acceptable liquid composition according to claim 1, containing from about 2% to about 6% wt. carbidopa and arginine, while the pH of the specified liquid composition is from 8 to 9 at 25 ° C. 4. A pharmaceutically acceptable liquid composition according to claim 1, further comprising a pharmaceutically acceptable excipient selected from N-methylpyrrolidone, polyvinylpyrrolidone, propylene glycol, antioxidants, or combinations thereof. The pharmaceutically acceptable liquid composition according to any one of paragraphs. 1-4, further containing (i) water； (ii) entacapone or tolcapone； or (iii) both water and entacapone or tolcapone. 6. A kit for treating a neurological disorder selected from restless legs syndrome, Parkinson's disease, secondary parkinsonism, Huntington's disease (Huntington), parkinson-like syndrome1. Фармацевтически приемлемая жидкая композиция для лечения неврологического расстройства в совместной терапии с леводопой, содержащая аргинин и терапевтически эффективное количество карбидопы, причем указанная композиция содержит от примерно 1% до примерно 6% мас. карбидопы, имеет рН от примерно 8,0 до приме
