ABSTRACT
A major obstacle for the introduction of particulate or colloidal drug carriers to the pharma ceutical market is the lack of a large-scale production method yielding a product of a quality that is acceptable by the regulatory authorities (e.g., Food and Drug Administration). This is no problem for traditional drug carriers like emulsions for parenteral administration. These emul sions for parenteral nutrition were introduced into therapy in the 1950s. Hence an accepted pro duction method by high-pressure homogenization is available. The same technique was trans ferred to liposomes for large-scale production. For example, liposomes for the treatment of infant respiratory distress syndrome can relatively easily be prepared aseptically by highpressure homogenization. The aseptic production makes a final sterilization redundant, thus preventing potential impairment of the physical stability of the liposomes. Large-scale produc tion methods are also established for microparticles, e.g., spray drying or the solvent evapora tion method (Parlodel LAR Decapeptyl, and Enantone). In contrast, there are still major prob lems to the establishment of large-scale production methods for solid nanoparticles, e.g., polymeric nanoparticles. It is considered to be one of the major obstacles preventing the suc cessful introduction of the nanoparticles to the clinic and the pharmaceutical market. More than 30 years of intensive research has been invested in nanoparticle technology, the output in terms of products for the patient is rather low or practically nonexistent. To our knowledge, no prod uct for chronic treatment based on nanoparticle technology is on the market. The company Nycomed did recently introduce a nanoparticulate product, but only for diagnostic purposes and not for chronic application (Abdomed).
