Gastroretentive dosage forms of levodopa and carbidopa

The present disclosure provides self-regulating, oral, permeable, floating gastric retentive CD/LD compositions suitable for one or two daily administration. The composition provides sustained release with enhanced LD pharmacokinetic properties, such as reduced lag time, avoidance of low ebb levels, and reduced peak-to-valley ratio (Cmax/Cmin), as compared to commercially available CD/LD products. The composition provides sustained release of CD/LD from about 8 hours to about 14 hours without losing the gastro-retention property (GRS property) of the system, and collapses/squeezes upon release of at least about 80% of the drug (CD/LD) from the system. When administered or in contact with a medium that mimics gastric conditions, the compositions of the present disclosure float for about 45 minutes or less, swell for about 60 minutes or less to a swollen state that prevents their passage through the pyloric sphincter, and remain in the swollen state, meanwhile, stable therapeutic concentrations of the drug are