Use of percolation threshold as element of preformulation of orthopaedic cements used as drug delivery systems

Abstract

The theory of the percolation has been proposed to solve the following problem: "What is the probability that the center of a porous material immersed in a fluid is wet?" This theory used in biomaterial domain permit to determine the percolation threshold of orthopaedic cement associated with porogenic agent containing drug. 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 study 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 and make it possible to predict the behaviour of the drug delivery system according to the characteristics of component constituting the system.