ContinuousPolymer Coating/Encapsulationof Submicrometer Particles Usinga Solid Hollow Fiber Cooling Crystallization Method.

Currently, no technique is availableto continuously film coatnanosized drug particles with a polymer to produce large amounts offree-flowing coated particles. In this work, Eudragit RL 100 and poly(d,l-lactide-co-glycolide) (PLGA) werechosen as the coating polymers and Cosmo 55 (550 nm silica particles)as a surrogate for drug particles. After determining the cloud pointof the polymer solutions by UV spectrophotometry, we adopted the solidhollow fiber cooling crystallization (SHFCC) technique to continuouslycoat the submicrometer particles with the polymer. In this methodthe polymer solution containing a suspension of submicrometer particlesflows in the lumen of a solid polymeric hollow fiber. Controlled coolingof the polymer solution by a coolant on the shell side of the hollowfibers allows for polymer nucleation on the surface of the particles;the precipitated polymer forms a thin film around the particles, thethickness of which can be varied depending on the operating conditions.Scanning electron microscopy, transmission electron microscopy, energy-dispersiveX-ray spectrometry, laser diffraction spectroscopy, and thermogravimetricanalysis were all used to characterize the coatings. The results indicatethat a uniformly coated and free-flowing product can be achieved underoptimized conditions in the SHFCC and suitable posttreatments. Furthermore,scale-up of the method can be easily accomplished by using a largerSHFCC module containing a much larger number of solid hollow fibers.This method is easily adaptable for coating nanosized drug particlesas well. [ABSTRACT FROM AUTHOR]