Study in Advanced Parkinson's Disease Patients With Predictable Motor Fluctuations

Inclusion Criteria: 1. Men and women at least 30 years and older at the time of informed consent with advanced idiopathic Parkinson's disease with predictable wearing-off motor fluctuations with Hoehn and Yahr Stage II-III when "on." 2. Patients should be able to differentiate between the "ON" and "OFF" states with an average daily "OFF" time of ≥ 2.5 hours at study entry. 3. On a stable daily dose of LD of ≥ 400 mg but ≤1600 mg for at least 1 month prior to the screening visit. 4. Non CD/LD containing anti-Parkinson's medications should be kept at stable doses for 1 month prior to screening visit. Patients should be willing to keep their non LD containing medications consistently throughout the study duration. 5. Female patients of childbearing potential should be abstinent or continuing to practice and willing to continue throughout the study with appropriate contraceptives (defined as Nova ring, oral, injected, transdermal patch, implanted, or barrier). 6. Mini Mental State Examination (MMSE) ≥ 26 at screening visit. 7. Able to provide informed consent and willing to sign Health Insurance Portability and Accountability Act (HIPAA) authorization. 8. Able and willing to comply with the protocol, including availability for all scheduled study visits and blood sample collections. Must be under the observation of a competent care giver throughout the study participation. Exclusion Criteria: 1. Patients with atypical or drug-induced Parkinson's disease. 2. Patients with a known history of hypersensitivity to levodopa or carbidopa. 3. Patients who receive treatments with dopamine receptor blocking agents 4. Patients with a history of seizures except of childhood febrile seizure. 5. Patients with dementia. 6. Patients with a significant history of GI diseases (severe inflammatory bowel disease, irritable bowel disease, dyspepsia, gastro-esophageal reflux disease etc.) in the past five years. 7. Patients with any history of gastric surgery other than vagotomy and pyloroplasty. 8. Patients with an immune-compromised state. 9. Patients with clinically significant hepatic insufficiency with Child-Pugh total score of ≥ 5. 10. Patients with a calculated creatinine clearance (Clcr) \< 50 mL/min using the Cockcroft-Gault equation. 11. Patients who have a difficulty swallowing tablets. 12. Patient has participated in a clinical trial of an investigational drug or device within 30 days of the screening visit. 13. Patients with any other serious medical condition that, in the opinion of the Investigator would jeopardize the safety of the patient or affect the validity of the study results.