A polysorbate-based non-ionic surfactant can modulate loading and release of beta-lactoglobulin entrapped in multiphase poly(DL-lactide-co-glycolide) microspheres.
OBJECTIVE
The goal of the present paper was to investigate the role of a surfactant, Tween 20, in the modulation of the entrapment and release of beta-lactoglobulin (BLG) from poly (DL-lactide-co-glycolide) microspheres.


METHODS
Poly(DL-lactide-co-glycolide) microspheres containing BLG were prepared by a water-in-oil-in-water emulsion solvent procedure. Tween 20 was used as a surfactant in the internal aqueous phase of the primary emulsion. BLG entrapment efficiency and burst release were determined. Displacement of BLG from microsphere surface was followed by confocal microscopy observations and zeta potential measurements, whereas morphological changes were observed by freeze-fracture electron microscopy.


RESULTS
Tween 20 was shown to increase 2.8 fold the encapsulation efficiency of BLG without any modification of the stability of the first emulsion and the viscosity of the internal aqueous phase. In fact, Tween 20 was shown to be responsible for removing the BLG molecules that were adsorbed on the particle surface or very close to the surface as shown by confocal microscopy and zeta potential measurements. Tween 20 reduced the number of aqueous channels between the internal aqueous droplets as well as those communications with the external medium. Thus, the more dense structure of BLG microspheres could explain the decrease of the burst release.


CONCLUSIONS
These results constitute a step forward in the improvement of existing technology in controlling protein encapsulation and delivery from microspheres prepared by the multiple emulsion solvent evaporation method.
Rojas
J
J
University of Paris-Sud, School of Pharmacy, URA CNRS 1218, Châtenay-Malabry, France.
Pinto-Alphandary
H
H
Leo
E
E
Pecquet
S
S
Couvreur
P
P
Gulik
A
A
Fattal
E
E
D002626:Chemistry, Pharmaceutical / Q000379:methods*; D004337:Drug Carriers; D007782:Lactoglobulins / Q000737:chemistry*; D008863:Microspheres; D010316:Particle Size; D011098:Polyglactin 910 / Q000737:chemistry*; D011136:Polysorbates / Q000737:chemistry*; D013501:Surface-Active Agents / Q000737:chemistry*
D004337:Drug Carriers; D007782:Lactoglobulins; D011136:Polysorbates; D013501:Surface-Active Agents; D011098:Polyglactin 910