Problems in the intravenous administration of synthetic and natural fats for nutritional purposes

Summary and conclusion

Due to the high interfacial tension between water and natural fats it is almost impossible to produce stable emulsions of these substances by mechanical means. It was found that the addition of emulsifying agents which lower surface tension, make possible the formation of stable emulsions. These emulsifying agents were found to be toxic and hemolytic in direct proportion to their surface tension lowering power. Surface active substances render the capillaries more permeable as demonstrated with T-1824 and account for the occurrence of pulmonary edema and death from shock after intravenous administration.

The droplet size is the limiting factor in emulsion stability both in vitro and in vivo. Electrolytes and globulins tend to break most emulsions while albumin tends to stabilize them. Different emulsions break at varying rates when mixed with serum.

Theoretical considerations and the above work show that, the preparation of fine emulsions by chemical means without emulsifying agents, and the use of water soluble dicarboxylic fatty acids compounds (or other synthetic fatty acids free of surface active properties), are worthy of future investigation.