Synthetic biomimetic hydroxyapatite nanocrystals for anticancer drug delivery

Synthetic biomimetic hydroxyapatite nanocrystals [1] have been used like drug deliver specifically designed to act as prodrugs in the local treatment of bone tumors.[2] The inorganic hydroxyapatite nanocrystals can be implanted locally, at the site of an osteosarcoma, after surgery and act both as bone substitutes and as antitumoral drug releasing agents.[3] The final goal is that of inhibiting locally the tumor re-growth. Biomimetic hydroxyapatite nanocrystals which can be administered also by injection have been investigated in releasing different platinum–bisphosphonate complexes against human cervical, colon, and lung cancer cells as well as against osteosarcoma cells.[4] In the present work we have investigated the antitumoral drug delivering performance of biomimetic hydroxyapatite nanocrystals which can be both implanted and administered by injection. We have investigated the role of some chemical physical characteristics of the biomimetic hydroxyapatite nanocrystals like structure, degree of crystallinity, morphology, dimensions in the nano scale, stoichiometry, Ca/P molar ratio, surface area in influencing the adsorption, as well as the release of different active antitumoral drug molecules. In particular we have studied a derivative of gold(III)-dithiocarbamato family compounds, named AUL12 ([AuIIIBr2(ESDT)], ESDT: ethylsarcosinedithiocarbamate) whose anticancer activity has been demonstrated in vivo on human tumor xenografts and in vitro on several cell lines including the human osteosarcomas SAOS 2 and U2OS cells.[5,6] AUL12 was delivered by biomimetic hydroxyapatite nanocrystals in order to estimate their adsorption and release kinetic in physiological condition as a function of the different chemical physic characteristic of the apatite nanocrystals.