Patent ID: 8685464

Claim:
A method for improving the storage stability of a kit comprising a particulate composition and an aqueous solution adapted for forming a bone graft substitute cement upon mixing, wherein the kit includes calcium phosphate powders reactive to form brushite in the presence of water and a carboxylic acid, the method comprising: i) packaging a monocalcium phosphate monohydrate powder and a Î²-tricalcium phosphate powder in separate containers in the kit; ii) packaging a calcium sulfate hemihydrate powder within a separate container in the kit or admixed with one or both of the monocalcium phosphate monohydrate powder and the Î²-tricalcium phosphate powder, the calcium sulfate hemihydrate present in an amount of 50 weight percent to about 90 weight percent based on the total weight of the particulate composition; and iii) packaging the carboxylic acid in the kit either in the form of a crystalline powder or dissolved in the aqueous solution, with the proviso that when the carboxylic acid is dissolved in the aqueous solution, it is added to the solution after radiation sterilization of the aqueous solution.