Synthesis and characterization of hydrotalcite-ATP intercalates

As a model for a drug delivery system, the intercalation of adenosine triphosphate (ATP) into hydrotalcite, a layered double hydroxide (LDH) of magnesium and aluminum, was studied. Well-crystallized pure hydrotalcite with nitrate ions in the interlayer (LDH-NO3) was formed by dropwise addition of a mixed solution of magnesium and aluminum nitrates to a sodium hydroxide solution. To intercalate ATP into hydrotalcite, LDH-NO3 was put in an ATP solution at pH 7 (ion exchange method). It was found that interlayer nitrate ions were completely exchanged with ATP and that the interlayer distance doubled. Further, a mixed solution of ATP, magnesium, and aluminum ions was added dropwise to a sodium hydroxide solution (coprecipitation method) and it was found that the product contains ATP.