Dopamine-loaded poly(D,L-lactic-co-glycolic acid) microspheres: new strategy for encapsulating small hydrophilic drugs with high efficiency.

The effective controlled release of small hydrophilic drugs from poly(d,l-lactic-co-glycolic acid) (PLGA) microspheres has remained a challenge, largely due to the difficulty of loading a large amount of the drug inside the microspheres, owing to the hydrophilicity of the drugs. This study provides a new strategy for increasing encapsulation of small hydrophilic drugs inside PLGA microspheres by utilizing noncovalent, physical adsorption between hydrophilic drugs and emulsifying polymers of poly(vinyl alcohol) and pluronic. An order of magnitude increase in drug loading efficiency from 2.7 to 18.6% for dopamine, a model small hydrophilic drug, was achieved. The large amount of dopamine-loaded PLGA formulation herein could be useful for the treatment of Parkinson's disease.