Calcium sulphate-based cements containing cephalexin.

Cephalexin containing gypsum and apatite/gypsum cements have been synthesised. The presence of cephalexin into the cements does not alter neither the physico-chemical behaviour of the cements nor produce structural changes on them. These cements behave as drug delivery systems when soaked in simulated body fluid. The release of the drug is different depending on the composition. For gypsum cements, the cephalexin is quickly released, helped by a dissolution process of the matrix, whereas the drug release is more controlled by the hydroxyapatite presence in hydroxyapatite/gypsum samples. Apatite containing cements do not only show a different drug release process, also the paste viscosity is lower and a faster formation "in vitro" of an apatite-type layer on their surface is observed.