Controlled adsorption and release onto calcium phosphates materials and drug delivery applications

A Barroug,S Cazalbou,C Rey,S Sarda,H Noukrati,F Errassifi,M.J Glimcher,C Combes

doi:10.1051/matecconf/20130503002

Abstract

The adsorptive properties of synthetic calcium phosphates analogous to bone mineral were examined with respect to cisplatin and risedronate, two biological active drugs; the uptake and release experiments were carried out under various conditions in order to understand the basic mechanism of interaction. The effect of temperature and solution composition were highlighted and discussed. The adsorption results obtained for the therapeutic agents demonstrated that, depending on the conditions investigated (nature of the sorbent, concentration range, ionic composition, temperature. . . ), the shape of the isotherms is of Freundlich or Langmuir type. The adsorption is described as an ion-exchange process in dilute solutions, while the interaction appears to be reactive for concentrated solutions (dissolution of mineral ions from the apatite substrate and formation of soluble calcium complex and/or precipitation of calcium salts involving sorbate molecules). The information gained on the surface reactivity of calcium phosphate were exploited to associate an antibiotic to calcium phosphate cements for drug delivery applications. The specimens were obtained by combination of calcium phosphate and calcium carbonate powders upon mixing with water. The physicochemical properties of the paste were altered by the drug loading method (in the liquid or solid phase). Thus, a dose-dependent effect was noticed for the paste setting time, hardening and the release process.

Highlights

In the last decades, calcium phosphate (CaP) materials have received major attention in the biomedical field mainly for their compositional resemblance with the mineral phase of bone and their biological properties
Typical X-ray diffraction patterns (XRD) and infrared spectra characteristics of apatite powders were obtained for the prepared specimens
The adsorption of risedronate molecules on apatite surface as a function of contact time showed that the process occurred very rapidly in KCl solution (1 mM), while it was relatively slow when phosphate species were added to the medium

Summary

Introduction

Calcium phosphate (CaP) materials have received major attention in the biomedical field mainly for their compositional resemblance with the mineral phase of bone and their biological properties. Considerable effort and large number of studies have been devoted to develop CaP based bioceramics in vivo for bone replacement or repair as well as the use of these materials as carriers to deliver therapeutic agents in the skeletal systems [1,2,3]. The phenomena (interaction mechanisms and driving forces) occurring at the interface between synthetic CaP and the surrounding environments remain not totally controlled. The objective of this work is (i) to determine the in vitro basic binding and release profiles and mechanisms of interaction of pharmaceuticals with biomimetic calcium phosphates nanoparticles, and (ii) to report in a preliminary study on the preparation of a cement and its combination with antibiotics for the treatment of bone infections

Objectives

Methods

Results