NMR techniques in drug delivery: application to zein protein complexes.

Zein is a protein containing a large amount of nonpolar amino acids, which has shown the ability to form aggregates and entrap solutes, such as drugs and amino acids. NMR techniques were used to detect binding interactions and measure affinity between zein and three different drugs: tetracycline, amoxicillin and indomethacin. The release study of zein microparticle formulations containing any of these drugs was confronted with the affinity results, showing a remarkable correlation. The feasible methodology employed, focused in the functionality of the protein-drug interaction, can be very promising for the rational design of appropriate drug vehicles for drug delivery.