A process for the release of a biologically active species comprising the steps of: providing a mesoporous oxide-based material having structural order and at least one level of porosity; fixing or immobilizing said biologically active species in said ordered mesoporous oxide; and providing said ordered mesoporous oxide with said fixed or immobilized biologically active species in vivo thereby realizing intraluminally induced substantially pH-independent supersaturation of said biologically active species resulting in enhanced transepithelial transport; wherein said biologically active species is a poorly soluble therapeutic drug classified as belonging to Class II or Class IV of the Biopharmaceutical Classification System and said ordered mesoporous oxide has a pore size in the range of 4 to 14 nm.