Selective Loading and Prolonged Release of 5-Fluorouracil in the Nanoconfined Interlayer Space of Montmorillonite

Montmorillonite was used as a carrier for the anticancer drug 5-fluorouracil (5FU). The selective loading of 5FU into the nanoconfined interlayer space of montmorillonite was achieved by rinsing off the weakly bonded 5FU from the external surface. The 5FU loading content in montmorillonite was 3.2 mass%. The intercalated 5FU was in an amorphous state and might be arranged as a roughly vertical monolayer in the interlayer space of montmorillonite. The intercalated 5FU showed a high thermal stability due to the protection of the montmorillonite layers. The release profiles of the intercalated 5FU were well fitted with the modified Korsmeyer-Peppas model. The montmorillonite exhibited a prolonged release of 5FU due to the restriction of the outward diffusion of intercalated 5FU. The 5FU/montmorillonite system has promising potential for oral administration for colonspecific delivery.