Composition influence on delivery ability of hydroxyapatite cements

Abstract

Hydroxyapatíte cements were dívided in two parts, a solid part composed by a mixture of hydroxyapatite, gypsum and t\vo polymers, sodium alginate and poly-N-vinyl-2-pyrrolidone anda liquid part formed by a mix­ture of sa.lts, potassium sulphate and potassium phosphate in water solution, were prepared. All the formulations Were doped with cefazolin and ciprofloxacine. The kinetics of drug delivery in buffer phosphate was studied, The results were adjusted to the Higuchi model regulated by the diffusion in two steps1 conditioned by the drug exposed at the :sample surface in first place, anda second step oriented by the diffusion through the matrix until a:chieving the surface and from these one to the solution. One \Veek after initiating the study, the influenceofthe gypsum andinhlbitors contents, on the liberated antibiotic c¡uantity was determine<!, oscillating between 10-50 %, de­pends on drug type and the formulation. The in verse effect of gypsum quan􀥧 tity, and direct effect ofthe inhibitor quantity, on the líberated drug, occurs in both cases, f'or the reaction coropetition that has between the gypsum with potassium phosphate and sodium alginate. On the other band, the authors discussed and proved that do not exist difíerences between drug delívery when studying the accelerator/inhibitor relationship in case of ciprofloxacine and on the contrary if it is talking about cefazolin. These results allow to val u e the real possibilíty to obtain a hydroxyapatite cement of national production.