In some cases, the intravenous administration of drugs or nutrients is the only therapy option. Especially in emergency medicine or during operations there may be a need to ensure that drugs are being distributed throughout the whole body within seconds. This is also the case in situations where patients are unable to take drugs orally or when the gastrointestinal tract does not function properly, then intravenous administration of actives or nutrients is the only alternative.
A number of liquids with different chemical compositions are applied in parenteral nutrition TPN). Depending on the weight and age of the patient as well as on the duration of the TPN period, blends consisting of amino acids, hydrocarbons, vitamins, minerals and fat are applied. In the later case as well as in the parenteral application of lipophilic drugs, typically liposomes, oil in water (O/W) emulsions, mixed micelles and suspensions are employed. The excipients applied in these systems must be toxicologically harmless and metabolized. In order to prevent serious side effects such as thrombosis and embolism, the particle size of the delivery system should not exceed 500 nm. The only emulsifiers applied today on industrial scale in parenteral emulsions are phospholipids because they are effective toxicologically safe and biodegradable emulsifiers.