| abstract |
Compositions and methods for delivering agents across cell membranes are disclosed. The compositions include an agent to be delivered, a viscous material, such as a hydrogel, lipogel or viscous sol, and, optionally, a carrier that includes a ligand that binds to or interacts with cell surface receptors. The agent to be delivered binds to or otherwise interacts with cell surface receptors, is attached, either covalently or ionically to a molecule that binds to or interacts with a cell surface receptor, or is associated with the carrier. Agents to be delivered include bioactive compounds and diagnostic agents. The compositions have an apparent viscosity roughly equal to the viscosity of the cytosol in the cell to which the agent is to be delivered. The rate of cellular internalization is higher when the viscosity of the viscous material and that of the cytosol in the cell are approximately the same, relative to when they are not the same. The compositions enhance cellular entry of bioactive agents and diagnostic materials when administered vaginally, nasally, rectaly ocularly, orally, or to the respiratory or pulmonary system. |