Study to Evaluate Safety/Duration in Stomach of Extended Release Capsules Containing Memantine Hydrochloride in Healthy Adults

To assess how long memantine hydrochloride (HCl) (50 mg) extended release capsules stay in the stomach as determined by imaging assessment (MRI or abdominal ultrasound). To evaluate the safety of a memantine HCl extended release capsule formulation

This is a single centre, open label, single dose study in healthy adult subjects. Eligible individuals will be admitted to an inpatient unit in two or more cohorts. Enough eligible individuals will be admitted allowing for the enrollment of the Sentinel (n= 2) and Main Group (total of n=8 in Main), and an optional Supplemental Group (n= 6), if required. All enrolled subjects will be dosed with a single administration of an extended release capsule containing memantine hydrochloride (LYN-057), 50 mg. Dosing will be conducted in an inpatient clinical unit, with access to an acute care facility. Subjects will remain in the inpatient unit for 7 days after dosing. During this time, subjects will undergo intermittent imaging assessments for gastric retention \[magnetic resonance imaging (MRI) and abdominal ultrasound (U/S)\], safety assessments, blood sampling for evaluation of memantine pharmacokinetics (PK), and faecal collections for assessments of formulation components and bowel movement characteristics. Subjects will return to the clinic for PK sampling and safety assessments on Days 10, 15, 22 and Day 29 (End of Study Visit). In addition, some subjects may continue to perform faecal collection and/or may undergo imaging assessments on Day 10 based on clinical criteria. On Day 29 (End of Study Visit), subjects will undergo final safety and PK assessments and will be discharged from the study.