Selective loading of 5-fluorouracil in the interlayer space of methoxy-modified kaolinite for controlled release

Methoxy-modified kaolinite was used as a novel carrier for anticancer drug 5-fluorouracil (5FU). The selective loading of 5FU into the interlayer space of methoxy-modified kaolinite was achieved because the weakly bonded 5FU on the external surface was removed off by facile water rinse. The intercalated 5FU has strong affinity (electrostatic force and hydrogen bonding) with the interlayer surface of kaolinite, and its release was controlled because of the diffusion restriction of the kaolinite lamellar layers and the strong affinity between 5FU and kaolinite. The controlled release of 5FU from methoxy-modified kaolinite in simulated colonic fluid (pH 5.5) makes it be of potential use to administer an oral formulation of 5FU for colon specific delivery.