The objective of our study was to prepare nano- and microparticles economically considering
some practical parameters such as size and
encapsulation efficiency as well as ability of particle recovery. Bovine serum albumin
(BSA) model protein was encapsulated by poly(d,l-lactideco-
glycolide) (PLGA) using a multiple water-in-oil-in-water emulsion-solvent evaporation
technique. The effect of three surfactants: polyvinyl
alcohol, poloxamer, and polyvinyl pyrrolidone, used in the outer water phase, on the
properties of particles was investigated. The emulsifier/PLGA
mass ratio played an important role in the preparation procedure of the particles.
This ratio was found to be approximately 1 for polyvinyl alcohol
(PVA) if the aim was to formulate nanoparticles with narrow size distribution (<220
nm), high yield and good encapsulation efficiency (>90%).
Although, a ratio of 2:1 was sufficient to produce submicron particles by poloxamer
with high yield, more than 70% and 90% encapsulation
efficiency required minimum 4 and 10 emulsifier/PLGA mass ratio, respectively. Five
times more PVA and 10 times more poloxamer than the
PLGA mass were necessary to obtain nanoparticles which were easy to redisperse after
centrifugation. Microparticles released more BSA than
nanoparticles prepared by PVA, however, the situation was reverse with poloxamer.
Microparticles formulated by polyvinyl pyrrolidone (PVP)
showed the fastest in vitro release.