The purpose of this study is to investigate the safety, tolerability and pharmacokinetics of a predefined dose range of co-administered Baclofen and Memantine in non-obese (Part A) and obese (Part B), otherwise healthy subjects.

Inclusion Criteria:

1. Adult males or females aged 18 to 45 years inclusive;

2. Subjects with body mass index:

   For Part A: ≥18 kg/m² and ≤25 kg/m²; For Part B: ≥33 kg/m² and ≤40 kg/m².

3. Subjects with a total body weight of ≥50 kg (Part A and Part B);

4. Subjects who are healthy as determined by the Investigator based on pre study medical history, physical examination, vital signs (blood pressure, pulse rate, respiratory rate and body temperature) and 12-lead ECG at screening and each admission;

5. Subjects whose clinical laboratory test results are not clinically relevant and are acceptable to the Investigator at screening and each admission;

6. Aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase and bilirubin ≤1.5 x upper limit of normal (ULN);

7. Subjects who are negative for hepatitis B surface antigen (HBsAg), hepatitis C antibody and human immunodeficiency virus (HIV) I and II tests at screening;

8. Subjects who are negative for drugs of abuse and alcohol tests at screening and each admission;

9. Subjects who are non-smokers or who have not smoked or used nicotine-containing products for at least 3 months prior to screening;

10. Subjects with an estimated creatinine clearance ≥100 mL/minute for male subjects or

    ≥90 mL/minute for female subjects (Cockcroft-Gault method) at screening;

11. Subjects who are able and willing to give written informed consent.