PLASMA-PROTEIN ADSORPTION PATTERNS ON EMULSIONS FOR PARENTERAL ADMINISTRATION - ESTABLISHMENT OF A PROTOCOL FOR 2-DIMENSIONAL POLYACRYLAMIDE ELECTROPHORESIS

The two-dimensional polyacrylamide electrophoresis (2-D PAGE) of the p lasma protein adsorption pattern previously established for polymeric nanoparticles was modified and transferred to oil in water emulsions f or intravenous administration. The emulsions were incubated with citra ted plasma, and separation from excess plasma was performed by centrif ugation under optimized conditions: 15 000 g and three washing steps w ith 0.05 M phosphate buffer, pH 7.4. With this sample preparation, coa lescence of droplets could be avoided and an unchanged surface area ma intained, in addition the phosphate buffer minimized artificial IgG ad sorption. Critical factors affecting sensitivity were contamination of the sample by oil residues and the use of thiourea in the immobilized pH gradients. Changes in the protein adsorption pattern caused by alt ered surface properties of the emulsion (i.e. adsorbed Poloxamer 407) were detectable when applying the optimized protocol. Knowledge of the protein adsorption patterns and their correlation to in vivo behavior opens the perspective for the development of intravenous emulsions fo r controlled drug delivery.