title: Understanding reflection behavior as a key for interpreting complex signals in FBRM monitoring of microparticle preparation processes.
abstract: The application of focused beam reflectance measurement (FBRM) was studied in a larger scale PLGA microparticle preparation process for monitoring changes of the particle size and the particles' surface properties. Further understanding how these parameters determine the chord length distribution (CLD) was gained by means of single object measurements and data of monodisperse microparticles. It was evaluated how the FBRM signal is influenced by the surface characteristics of the tested materials and the measuring conditions. Particles with good scattering properties provided comparable values for the CLD and the particle size distribution. Translucent particles caused an overestimation of the particle size by FBRM, whereas the values for transparent emulsion droplets were too low. Despite a strong dependence of FBRM results on the optical properties of the samples, it is a beneficial technique for online monitoring of microparticle preparation processes. The study demonstrated how changing reflection properties can be used to monitor structural changes during the solidification of emulsion droplets and to detect process instabilities by FBRM.
authors.affiliation: Sandoz GmbH, Sandoz Development Center Austria, Biochemiestrasse 10, A-6250 Kundl, Austria. kerstin.vay@sandoz.com
authors.forename: Kerstin
authors.initials: K
authors.lastname: Vay
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Friess
authors.forename: Stefan
authors.initials: S
authors.lastname: Scheler
mesh_terms: D004339:Drug Compounding / Q000295:instrumentation / Q000379:methods*; D019344:Lactic Acid / Q000737:chemistry; D009862:Online Systems; D010316:Particle Size; D011100:Polyglycolic Acid / Q000737:chemistry; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011137:Polystyrenes / Q000737:chemistry; D013499:Surface Properties
chemical_list: D011137:Polystyrenes; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid