Inclusion Criteria:  Male or female aged 50 to 80 Body mass index 17.5 to < 35 kg/m2, inclusive at the time of screening Mini-Mental State Score of ≥ 25 points at screening Must provide written informed consent  Exclusion Criteria:  Abnormalities in vital signs at screening or baseline Clinically significant abnormal hematology or biochemistry values, as determined by the investigator at screening and/or baseline. Previous clinically significant systemic illness or infection within the past 4 weeks prior to screening or baseline, as determined by the investigator Clinically significant ECG abnormalities Use of tobacco- or nicotine-containing products in the past month or unwillingness to abstain during study participation Participation in another clinical study of a drug or device Known allergy to the study drug (Xanamem®) or any of the excipients Subjects who are likely to be unable to comply with the study schedule and/ or subjects with an inability to communicate well with the investigator Positive testing for human immunodeficiency virus (HIV), hepatitis B surface antigen, or hepatitis C antibodies at screening Subjects with a history of drug abuse or addiction in the past 5 years. Evidence of alcohol abuse (defined as greater than 21 standard units per week for males and greater than 14 standard units per week for females)