A process for the preparation of a camsylate salt ((1S)-(+)-10 camphorsulfonic acid) 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-1'2'-imidazole]-4"-amine is disclosed as well as pharmaceutical compositions containing the salt and therapeutic uses of the salt for treating A²-related pathologies such as Alzheimer's Disease, Down's Syndrome, ²-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.
