Cookies on this website

We use cookies to ensure that we give you the best experience on our website. If you click 'Accept all cookies' we'll assume that you are happy to receive all cookies and you won't see this message again. If you click 'Reject all non-essential cookies' only necessary cookies providing core functionality such as security, network management, and accessibility will be enabled. Click 'Find out more' for information on how to change your cookie settings.

Negatively charged poly(lactic-co-glycolic acid) (PLGA) microspheres encapsulated with hydrophilic drugs have been successfully prepared by a solidin-oil-in-water (s/o/w) solvent evaporation method in the presence of anionic surfactants, sodium dodecyl sulfate (SDS), and dioctyl sodium sulfosuccinate (DSS), and nonionic surfactant polyvinyl alcohol (PVA). The effects of microencapsulation methods, surfactants types, and surfactant concentrations on the properties of microspheres were studied. Amoxicillin (AMX) was chosen as a hydrophilic model drug, and its encapsulation efficiency (EE) and in vitro release profiles were measured. The s/o/w method achieved higher EE of 40% in PLGA microspheres using surfactant SDS compared with the conventional water-in-oil-in-water (w/o/w) method (about 2%). Triphasic release profiles were observed for all PLGA microspheres (s/o/w) with slight drug burst, a slow diffusion-controlled release within the period of about 7 days and followed by the degradation-controlled sustained release for further 30 days. Smaller particle size and surface charge were achieved for s/o/w method than w/o/w method using the same anionic surfactants, and smooth surface and less porous interior matrix. The s/o/w method effectively encapsulated AMX into anionic PLGA microspheres using anionic surfactants, and these negatively charged PLGA microspheres represented an attractive approach for the controlled release of hydrophilic drugs. © 2008 Wiley-Liss, Inc. and the American Pharmacists Association.

Original publication




Journal article


Journal of Pharmaceutical Sciences

Publication Date





2377 - 2389