ABSTRACT
Nanotechnology is one of the fastest-growing ›elds in engineered materials science and, focusing primarily on pharmaceutics, has been touted as the formulation salvation for many of the most promising new therapeutic agents. It seems that as we delve deeper into the workings of many of the tough-to-treat disease states, we ›nd relatively small molecules or short lengths of protein that demonstrate excellent ef›cacy and speci›city of treatment. Unfortunately, many of these new chemical and biological entities (NCEs and NBEs) exhibit solubilities similar to the glass and plastic vessels in which they were formed. There is little point in administering an oral dose of an extremely effective active pharmaceutical ingredient (API) if it passes through the gastrointestinal (GI) tract like a tomato seed, undissolved and unabsorbed. Typically, the new APIs are delivered in solution form with enormous amounts of solvents, solubilizers, and surfactants by oral or parenteral routes. However, the quantities of solubilizers and surfactants employed can lead to health issues such as sensitivity and impaired renal/hepatic function. The development of a nanoparticulate form of an API does not necessarily solve the solubility issues, but it does maximize the surface area from which slow dissolution can occur. In addition, development of amorphous nanoparticles from a crystalline active can drastically increase the intrinsic dissolution rate by eliminating the energy requirement needed to disrupt the crystalline lattice. Administration is also ineffective if the API cannot penetrate the physical barriers it faces, such as the skin or the cell membrane, or the chemical barriers such as the blood-brain barrier or the blood-ocular barrier. This is the role of surface modulation.
