[General characteristics and problems of the galenic aspects of fat emulsions]

The development of a clinically applicable intravenous fat emulsion has a long history. The gain of knowledge about the best lipid and emulsifying system had an intermittent development and led to three generations of distinct fat emulsions. For the evaluation of a fat emulsion it is necessary to compare the results of the same generation only. In the past, many misinterpretations came from mixing the results of different generations. It can be stated that by considering the contraindications, application schedules and basal galenic aspects, only minimal side effects from a parenteral administration of fat emulsions can be seen. Today the most important aspects of parenteral nutrition with fat emulsions are the galenic ones, which are often overlooked. The staining of the liposomes of the fat emulsions with 2% OSO4 make electron microscopic investigations of the liposomes possible after mixing them with carbohydrates, amino acids, electrolytes, vitamins and trace elements. The liposomes of soybean oil emulsions in different "All In One" (AIO) solutions have been under current investigations. The results demonstrated that the liposomes of fresh AIO-solutions carry highly osmiophilic inclusion bodies. Prolonged storage led to further alterations, as change of shape, loss of osmiophility and finally formation of liposomes ghosts. In solutions kept at 4 degrees C those changes developed between the 1st and 2nd month of storage, whereas storage at 22 degrees C was harmless within 48 h only. Therefore, it is recommended that already prepared AIO solutions are kept at 4 degrees C and used as soon as possible.