F. Kedzierewicz et al., PREPARATION OF SILICONE MICROSPHERES BY EMULSION POLYMERIZATION - APPLICATION TO THE ENCAPSULATION OF A HYDROPHILIC DRUG, Journal of microencapsulation, 15(2), 1998, pp. 227-236
The objective of this work was to evaluate the ability of appropriate
silicone elastomers to encapsulate hydrophilic compounds in microspher
es prepared according to a multiphase emulsion-polymerization process.
The particle size of the microspheres can be modified by controlling
the usual emulsification parameters, such as the viscosity of the diff
erent phases, shear rates and surface activity properties of additives
. The encapsulation efficiencies of a hydrophilic drug, propranolol hy
drochloride, were very high but its release rates were very slow. Osmo
tic agents such as glycerol and propylene glycol did not enhance the r
elease rate, whereas it was slightly increased by both sodium chloride
addition and higher drug loading.