Transparent porous sustained-release body and method for producing the same, and kit of sustained-release body, sustained-release apparatus, and sustained-release method

A transparent porous sustained-release body comprising an inorganic monolithic porous body including a skeleton body of an inorganic compound and air gaps having a three-dimensional continuous network structure, and a sustained-release liquid absorbed into said air gaps,

• wherein
• said inorganic monolithic porous body is opaque at an initial state, which is a state before absorption of said sustained-release liquid in which air exists in said air gaps,
• a refractive index of said sustained-release liquid and a refractive index of said skeleton body are the same within an error range such that a portion in which said sustained-release liquid is absorbed into said air gaps changes to transparent or semitransparent;
• said skeleton body has a three-dimensional continuous network structure,
• said air gaps have a two-step hierarchical porous structure including through-holes and pores, the through-holes being formed in voids in said skeleton body and having a three-dimensional continuous network structure, and the pores extending from a surface to an inside of said skeleton body and being dispersively formed on said surface,
• a most frequent pore diameter in a pore diameter distribution of said pores is within a range of 2 nm or more and 200 nm or less,
• a most frequent pore diameter in a pore diameter distribution of said through-holes is equal to or more than 5 times of said most frequent pore diameter of the pores, and within a range of 0.1 μm or more and 100 μm or less, said refractive index of said skeleton body is 1.45 to 1.5, and said refractive index of said sustained-release liquid is 1.4305 to 1.48 when said most frequent pore diameter of said through-holes is more than 0.6 μm, 1.424 to 1.5012 when said most frequent pore diameter of said through-holes is more than 0.3 μm and equal to or less than 0.6 μm, and 1.375 to 1.528 when said most frequent pore diameter of said through-holes is equal to or less than 0.3 μm.