The study is carried-out to describe and compare the plasma pharmacokinetics of levodopa and carbidopa after oral single-dose administration of 100 mg levodopa plus 25 mg carbidopa by means two fixed combination products (test: Isicom® 100/25 mg; reference: Nacom® 100/25 mg).

Additionally, to describe and compare the safety and tolerability of the two investigational treatments administered to healthy subjects.

Isicom® 100/25 mg and Sinemet® (Trade name in Germany: Nacom®) 100/25 mg are authorised fixed-combination products containing 100 mg levodopa plus 25 mg carbidopa. These two formulations were tested for bioequivalence in 1997 (DESITIN trial № LCD-010/K); based on the regulatory provisions in place at that time (CPMP/EWP/QWP/1401/98), the two formulations could be accepted to be bioequivalent.

The present study is proposed to be conducted in order to verify and confirm the bioequivalence of Isicom® 100/25 mg (test formulation) and Nacom® 100/25 mg (reference formulation) in agreement with the pertinent regulatory guidance that came in place 2010 (CHMP Guideline On The Investigation Of Bioequivalence - CPMP/EWP/QWP/1401/98- Rev. 1/ Corr - Jan.2010).

Inclusion Criteria:

• Males or females (females of non-childbearing potential or of childbearing potential while taking medically appropriate contraception)
• Race: Caucasian
• Age: 18 to 45 years
• Body weight: 50 100 kg
• Body Mass Index: 18 26 kg.m-2
• Healthy based on the screening examination
• Willing and able to provide informed consent

Exclusion Criteria:

• Previous participation in this trial or participant in any other trial during the last 90 days
• Donation of blood or plasma during the last 90 days or a history of blood loss exceeding 300 mL within the last 3 months
• History of any clinically relevant allergy including hypersensitivity to levodopa or carbi-dopa and related excipients
• Presence of any acute or chronic infection
• Presence or history of any relevant co-morbidity
• Resting systolic blood pressure > 160 or < 90 mmHg, diastolic blood pressure > 95 or < 50 mmHg
• Clinically relevant ECG-abnormalities, in particular prolonged QTc(F) of > 450 msec in males and > 460 msec in females
• Presence of any relevant abnormality in the laboratory safety tests, especially low haemo-globin (< 120 g/L in females and (< 136 g/L in males) and increased liver enzymes (2 times the upper limit of the normal range)
• Positive serology for HBsAg or anti HCV
• Positive HIV test
• Positive alcohol or urine drug test at screening
• Regular use of any prescription medicine (except for contraceptives) or over-the-counter product, herbal product, hormone supplement, etc. in the 30 days prior to the Screening visit
• History of alcohol and/or drug abuse and/or daily use of > 30 g alcohol
• Smoking more than 10 cigarettes/day or equivalent of other tobacco products
• Suspicion or evidence that the subject is not trustworthy and reliable
• Suspicion or evidence that the subject is not able to make a free consent or to understand the information in this regard.
• Positive pregnancy test
• Lactating
• Female subjects of child-bearing potential not using appropriate contraception in the 3 weeks prior to enrolment until two weeks after the last dose of the trial medication