Intercalation of anticancer agent cytarabine and its related compounds into γ-titanium phosphate

The intercalation of nucleic acid-related compounds which have the pyrimidine structure into the layered titanium phosphate, Ti(H2PO4)(PO4). 2H(2)O (gamma-TiP), was examined. The intercalation of cytosine derivatives such as anticancer agent cytarabine was successful. In addition, cytarabine release tests from the obtained cytarabine intercalation compound of gamma-TiP were performed in various kinds of solutions containing sodium ions. The release of cytarabine became slower by intercalation into the layered phosphate. Cytarabine release was strongly influenced by the pH value and the concentration of sodium ions in the test solution. In the reaction in aqueous solutions with higher concentrations of sodium ion and/or higher pH values, the ion-exchange of Na+ and protonated cytarabine in the intercalation compound and the disintegration of the layered structure of gamma-TiP occurred. On the other hand, in the solutions with the lower sodium ion concentration and the lower pH value, the layered structure of gamma-TiP was disintegrated and cytarabine in the interlayer region rearranged.