"What is the probability that the centre of a porous material immersed in a fluid is wet?" The theory of percolation, used in the bio-material domain, determines the percolation of threshold of orthopaedic cement associated with porogenic agent containing drugs. Porogenic agent containing Ibuprofen is introduced into phosphocalcic cement in order to ensure a sustained release as well as an interconnecting porosity. The granulometry and rate of introduced active agent are modified in order to styd the influence of such parameters on the kinetic release. The knowledge of the percolation threshold of this "drug delivery system" permits to establish the link between dissolution profile of the drug, porous network and characteristics of the system. It can be used as element of pre-formulation, making it possible to predict the behaviour of the drug delivery system according to the characteristics of component constituting the system.
