A major challenge in the treatment of diseases is the selective transport of active agents to the damaged tissue or organ. Cell membranes are the most important barriers for a targeted drug delivery. Another problem is the degradation or derivatization of free agents in the body which often reduces the specific effect of the drug at the target site. Also, active agents are distributed incorrectly or are changed in the body, which may lead to unwanted side effects. An already-tested way to circumvent these disadvantages is the manufacturing of particulate active ingredient formulations, where the active agent is bound into a polymeric shell or matrix.