The biologic response to titanium phosphate. A new synthetic mineral fiber.

: Titanium phosphate, a new manmade fiber, was evaluated by intratracheal and intraperitoneal techniques in rats and hamsters to assess the fibrogenic potential and possible hazard to man. Titanium phosphate fibers structurally resemble asbestos insofar as they are composed of bundles of submicronic fibers. A slight, dose-related fibrogenic response to the fiber was observed subsequent to the intratracheal injection of a 50- and 10-mg/kg but not 2-mg/kg dose in rats or any of these three doses in the hamster. Intraperitoneal administration of 10 or 2 mg/kg of the fibers in rats or hamsters induced no abdominal tumors considered related to treatment. In contrast, approximately 34% of rats given an intraperitoneal injection of 2 mg/kg of asbestos developed abdominal tumors; no tumors developed in hamsters injected with asbestos.