The drug being tested in this study is called roflumilast. Roflumilast is being tested as a potential treatment for Alzheimer's disease. This study will look at roflumilast combined with a medication called donepezil, and their ability to reverse mimicked Alzheimer's disease symptoms that have been brought on by administration of a drug called scopolamine.~The study will enroll up to 28 participants. Participants will be randomly assigned (by chance, like flipping a coin) to one of four treatment groups-which will remain undisclosed to the participant and study doctor during the study (unless there is an urgent medical need). All participants will receive the following treatments at varying time points throughout the study:~Roflumilast Dose A tablets~Donepezil 10 mg capsules~Placebo (dummy inactive pill) - this is a tablet or capsule that looks like the study drug but has no active ingredient~Scopolamine 0.5 mg subcutaneous injection.~All participants will be asked to take 2 tablets and 1 capsule and will receive a scopolamine subcutaneous injection on the first day of 4 separate study periods. Participants will then be assessed for how the scopolamine affects their mental processes and whether the study drug improves this.~This single-center trial will be conducted in England. The overall time to participate in this study is up to 95 days. Participants will make 7 visits to the clinic, including 4 separate periods of 2 days confinement to the clinic, and a follow-up assessment 14 days after the last treatment period.
The purpose of this study is to determine whether scopolamine-induced cognitive impairment is attenuated by the administration of roflumilast in combination with donepezil.