It is an open-label, balanced, randomized, five-treatment, five-period, five-sequence, multiple oral dose, crossover comparative bioavailability study of different strengths of carbidopa/levodopa extended-release tablets with carbidopa and levodopa tablets in normal, healthy adult human subjects under fasting and fed conditions. The primary objective of the study is to compare the pharmacokinetic profiles between WD-1603 extended-release formulations and carbidopa and levodopa tablets 25mg/100mg following three times a day after oral administration in fasting and fed conditions in healthy subjects and to compare relative bioavailability between treatments.

Study WD-1603-1005 is to compare the fluctuation index between WD-1603 extended-release formulations and Carbidopa and Levodopa Tablets following three times a day oral administration and the food effect on the initial absorption of levodopa in the morning in healthy subjects. At least 15 subjects will be enrolled at the beginning of the study and the order of receiving the Treatment A, B, C, D & E for each subject during all the periods of the the study will be determined according to a randomization schedule.

Inclusion Criteria:

1. Normal, healthy adult human volunteers between 18 to 45 years of age (both inclusive).
2. Having a Body Mass Index (BMI) between 18.5 to 29.9 (both inclusive), calculated as weight in kg/ height in m2, a minimum body weight of 50.0 kg.
3. Not having any significant disease or clinically significant abnormal findings during screening, medical history, clinical examination, laboratory evaluations, 12- lead ECG, and X-ray chest (P/A view) recordings.
4. In the case of female subjects:

a. Surgically sterilized at least 6 months prior to study participation or If of childbearing potential is willing to use a suitable and effective double barrier contraceptive method or intra-uterine device during the study and for at least 28 days after the last study drug administration.

And b. Serum Pregnancy test must be negative.

Exclusion Criteria:

1. Known hypersensitivity or idiosyncratic reaction to Carbidopa or Levodopa or any of the excipients or any related drug.
2. History or presence of any disease or condition which might compromise the hemopoietic, renal, hepatic, endocrine, pulmonary, central nervous, cardiovascular, immunological, dermatological, gastrointestinal, or any other body system.
3. Ingestion of a medicine (prescribed & over the counter (OTC) medication including herbal remedies and MAO inhibitors) at any time within 30 days before first dosing in Period I. In any such case, subject selection will be at the discretion of the Principal Investigator.