Thermodynamic signature of secondary nano-emulsion formation by isothermal titration calorimetry.
The stabilization of oil in water nano-emulsions by means of a polymer coating is extremely important; it prolongs the shelf life of the product and makes it suitable for a variety of applications ranging from nutraceutics to cosmetics and pharmaceutics. To date, an effective methodology to assess the best formulations in terms of thermodynamic stability has yet to be designed. Here, we perform a complete physicochemical characterization based on isothermal titration calorimetry (ITC) compared to conventional dynamic light scattering (DLS) to identify polymer concentration domains that are thermodynamically stable and to define the degree of stability through thermodynamic functions depending upon any relevant parameter affecting the stability itself, such as type of polymer coating, droplet distance, etc. For instance, the method was proven by measuring the energetics in the case of two different biopolymers, chitosan and poly-L-lysine, and for different concentrations of the emulsion coated with poly-L-lysine.
Dipartimento di Farmacia, Università di Napoli Federico II , via Domenico Montesano 49, 80131 Naples, Italy.
Iolanda
I
Fotticchia
Teresa
T
Fotticchia
Carlo Andrea
CA
Mattia
Paolo Antonio
PA
Netti
Raffaele
R
Vecchione
Concetta
C
Giancola
D002151:Calorimetry / Q000379:methods*; D048271:Chitosan / Q000737:chemistry; D004655:Emulsions / Q000737:chemistry*; D011107:Polylysine / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D013816:Thermodynamics
D004655:Emulsions; D011108:Polymers; D011107:Polylysine; D048271:Chitosan