title: Physico-chemical characterisation of PLGA nanoparticles after freeze-drying and storage.
abstract: Nanoparticles represent promising carriers for controlled drug delivery. Particle size and size distribution of the particles are important parameters for the in vivo behaviour after intravenous injection and have to be characterised precisely. In the present study, the influence of lyophilisation on the storage stability of poly(D,L lactic-co-glycolic acid) (PLGA) nanoparticles, formulated with several cryoprotective agents, was evaluated. Nanoparticles were prepared by a high pressure solvent evaporation method and freeze-dried in the presence of 1%, 2%, and 3% (m/v) sucrose, trehalose, and mannitol, respectively. Additionally, to all samples containing 3% of the excipients, L-arginine hydrochloride was added in concentrations of 2.1% or 8.4% (m/V). Dynamic light scattering (DLS), analytical ultracentrifugation and transmission electron microscopy (TEM) were used for particle characterisation before and after freeze-drying and subsequent reconstitution. In addition, glass transition temperatures were determined by differential scanning calorimetry (DSC), and the residual moisture of the lyophilisates was analysed by Karl Fischer titration. It was demonstrated that 1% sucrose or 2% trehalose were suitable to maintain particle integrity after reconstitution of lyophilised PLGA nanoparticles. The storage stability study over 3 months showed notable changes in mean particle size, size distribution, and residual moisture content, depending on the composition of the formulation.
authors.affiliation: Institut für Pharmazeutische Technologie, Goethe-Universität, Frankfurt am Main, Germany.
authors.forename: Melisande
authors.initials: M
authors.lastname: Holzer
authors.forename: Vitali
authors.initials: V
authors.lastname: Vogel
authors.forename: Werner
authors.initials: W
authors.lastname: Mäntele
authors.forename: Daniel
authors.initials: D
authors.lastname: Schwartz
authors.forename: Winfried
authors.initials: W
authors.lastname: Haase
authors.forename: Klaus
authors.initials: K
authors.lastname: Langer
mesh_terms: D002152:Calorimetry, Differential Scanning; D005612:Freeze Drying; D019344:Lactic Acid / Q000737:chemistry*; D008027:Light; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles; D010316:Particle Size; D011100:Polyglycolic Acid / Q000737:chemistry*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D012542:Scattering, Radiation; D014461:Ultracentrifugation
chemical_list: D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid