Pfizer Canada's manufacturing facility in Brandon, Manitoba is responsible for the global production of conjugated estrogens, the active pharmaceutical ingredient for the PREMARIN family of brands and DUAVEE / DUAVIVE brands. The conjugated estrogens are sourced from Canadian Equine ranchers in Manitoba and Saskatchewan. In addition, the site works closely with the Pfizer Equine Ranch, which conducts research on horse husbandry, physiology, nutrition, behavior and health that contains continuous technological advancements on horse management and welfare.

PREMARIN was first developed and approved in Canada in 1941.