Block copolymers at interfaces: interactions with physiological media

Triblock copolymers (also known as Pluronics or poloxamers) are biocompatible molecules composed of hydrophobic and hydrophilic blocks with different lengths. They have received much attention recently owing to their applicability for targeted delivery of hydrophobic compounds. Their unique molecular structure facilitates the formation of dynamic aggregates which are able to transport lipid soluble compounds. However, these structures can be unstable and tend to solubilize within the blood stream. The use of nanoemulsions as carriers for the lipid soluble compounds appears as a new alternative with improved protection against physiological media. The interfacial behavior of block copolymers is directly related to their peculiar molecular structure and further knowledge could provide a rational use in the design of poloxamer-stabilized nanoemulsions. This review aims to combine the new insights gained recently into the interfacial properties of block copolymers and their performance in nanoemulsions. Direct studies dealing with the interactions with physiological media are also reviewed in order to address issues relating metabolism degradation profiles. A better understanding of the physico-chemical and interfacial properties of block copolymers will allow their manipulation to modulate lipolysis, hence allowing the rational design of nanocarriers with efficient controlled release.