Dual-phase calcium phosphate cement composition

Dual-phase cement precursor compositions for forming a bone repair cement upon mixing for implantation, molding and manipulation during a work time, subsequent setting and hardening comprising:

• first and second discrete unmixed phases, each phase in the form of a paste which is not by itself capable of forming a cement, said first phase being aqueous and comprising a first calcium phosphate compound selected from the group consisting of dicalcium phosphate anhydrous, dicalcium phosphate dihydrate, or mixtures thereof and said second phase being non-aqueous and comprising tetracalcium phosphate, said first and second phases forming a biocompatible cement upon mixing, said first phase including an organic acid or salt thereof selected from the group consisting of citric acid, succinic acid, and mixtures of the foregoing in an amount effective to increase the work time of the biocompatible cement formed upon mixing relative to the work time to a similar cement prepared in the absence of said organic acid or salt thereof, said first phase further comprising a setting accelerator selected from the group consisting of monocalcium phosphate monohydrate and monocalcium phosphate anhydrous, said phases characterized upon mixing to allow manual forming and manipulation during a work time of about at least 30 seconds to about 10 minutes and subsequent setting and hardening.