Release mechanism from a microsphere of a silkworm chitin derivative studied by single microparticle injection and absorption microspectroscopy.

The release process of phenol blue from a dibutyrylchitin microsphere, prepared with chitin from a silkworm, into an aqueous solution was kinetically analyzed by single microparticle injection/manipulation and absorption microspectroscopy. The distribution ratio and the release rate of phenol blue in the single microsphere/water system were significantly influenced by the pH of the solution. These results are discussed in terms of the protonation of phenol blue and dibutyrylchitin, and the pore and surface diffusion in the pores of the microsphere.