A camsylate salt of (1r, 1 'R, 4R)- 4- methoxy- 5' -methyl- 6'- [5- (prop -1- yn 1 -yl)pyridin- 3- yl]- 3' H- dispiro[cyclohexane- 1, 2'- inden- r2' imidazole]- 4' -amine , pharmaceutical compositions containing the salt and therapeutic uses of the salt for treating Aß related pathologies such as Alzheimer' s Disease , Down' s syndrome, ß- amyloid angiopathy and conditions such as dementia including dementia of mixed vascular and degenerative origin , pre- senile dementia , senile dementia and dementia associated with Parkinson s disease, progressive supranuclear palsy or cortical basal degeneration.
