NZ 599544 Disclosed herein is a method comprising: (a) combining uniform, rigid, spherical, nanoporous calcium phosphate particles comprising a porous structure that defines an internal space； and an active agent； in the presence of a non-aqueous solvent under conditions sufficient for the active agent to enter internal space of the uniform, rigid, spherical, nanoporous calcium phosphate particles to produce active agent loaded uniform, rigid, spherical, nanoporous calcium phosphate particles； wherein the uniform, rigid, spherical, nanoporous calcium phosphate particles and the active agent are combined in the presence of the non-aqueous solvent under pressure； and (b) separating the non-aqueous solvent from the active agent loaded uniform, rigid, spherical, nanoporous calcium phosphate particles by evaporating the non-aqueous solvent under negative pressure (vacuum)； wherein said method comprises pre-wetting the uniform, rigid, spherical, nanoporous calcium phosphate particles with a non-aqueous solvent to remove gas present inside of the uniform, rigid, spherical, nanoporous calcium phosphate particles. Topical formulations comprising these uniform, rigid, spherical, nanoporous calcium phosphate particles enhance penetration of the active agent and are suitable for use in applications where it is desired to deliver an active agent to a subject.
