The influence of solvent polarity on the loading of ibuprofen in mesoporous hydroyapatites

Full text: Bioceramics are widely used as components in implants for bones and tooth restoration. Currently, methods and new advanced chemical processing strategies allow the incorporation of drugs in these materials [1]. By presenting biocompatible, osteoconductive and non-toxic properties hydroxyapatite (HAP) has been investigated with emphasis on adsorption of drug molecules, such as ibuprofen, which has been studied due to its advantages such as good pharmacological activity [2]. In the present study the influence of the polarity of the solvent on the loading of ibuprofen in mesoporous hydroxyapatite was investigated. Mesoporous hydroxyapatite was synthetized by co-precipitation method using casein as template. The mesoporous hydroxyapatite was placed in contact at room temperature with a 500 ppm ibuprofen solution prepared in various solvents as water (5% Na₂CO₃), ethanol and hexane for one hour at 130 rpm. Materials were characterized before and after the interaction with the drug by BET, XRD, FTIR, UV-Vis and CHN. XRD patterns indicated the formation of HAP with good crystallinity. The obtained nitrogen isotherms were type IV, characteristic of mesoporous materials. The pore size distribution presented average of 10-16 nm. The load capacities of ibuprofen on HAP were 67, 180 and 195 mg g^-1 in water, ethanol hexane, respectively. It suggested an increasing of loading capacity with decreasing of the solvent polarity. References: [1] M.Vallet-Regí, D. Arco. Bioceramics for drug delivery. Acta Materialia 61 (2013) 890-911. [2] M. Oner , E. Yetiz, Esin Ay, U. Uysal. Ibuprofen release from porous hydroxyapatite tablets. Ceramics International 37 (2011) 2117-2125. (author)