In vitro extended-release properties of drug-loaded poly(DL-lactic acid) nanoparticles produced by a salting-out procedure.

Savoxepine-loaded poly(DL-lactic acid) (PLA) nanoparticles were prepared using an emulsion technique involving a salting-out process which avoids surfactants and chlorinated solvents. After their formation, the nanoparticles were purified by cross-flow microfiltration and subsequently freeze-dried. The drug loading and the drug entrapment efficacy were improved by using savoxepine base rather than the methanesulfonate salt and by modifying the pH of the aqueous phase. A drug entrapment efficacy as high as 95% was obtained with a 9% drug loading. The overall yield of the procedure can rise up to 93%. In vitro release studies have demonstrated that by varying the mean size of the nanoparticles and their drug loading, the release of the drug from the nanoparticles can be modulated to last from several hours to more than 30 days, thus allowing the preparation of an injectable extended-release dosage form.