Continuous polymer coating/encapsulation of submicrometer particles using a solid hollow fiber cooling crystallization method

Dengyue Chen, Dhananjay Singh, Kamalesh K. Sirkar, Robert Pfeffer

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


Currently, no technique is available to continuously film coat nanosized drug particles with a polymer to produce large amounts of free-flowing coated particles. In this work, Eudragit RL 100 and poly(d,l-lactide-co-glycolide) (PLGA) were chosen as the coating polymers and Cosmo 55 (550 nm silica particles) as a surrogate for drug particles. After determining the cloud point of the polymer solutions by UV spectrophotometry, we adopted the solid hollow fiber cooling crystallization (SHFCC) technique to continuously coat the submicrometer particles with the polymer. In this method the polymer solution containing a suspension of submicrometer particles flows in the lumen of a solid polymeric hollow fiber. Controlled cooling of the polymer solution by a coolant on the shell side of the hollow fibers allows for polymer nucleation on the surface of the particles; the precipitated polymer forms a thin film around the particles, the thickness of which can be varied depending on the operating conditions. Scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectrometry, laser diffraction spectroscopy, and thermogravimetric analysis were all used to characterize the coatings. The results indicate that a uniformly coated and free-flowing product can be achieved under optimized conditions in the SHFCC and suitable posttreatments. Furthermore, scale-up of the method can be easily accomplished by using a larger SHFCC module containing a much larger number of solid hollow fibers. This method is easily adaptable for coating nanosized drug particles as well.

Original languageEnglish (US)
Pages (from-to)6388-6400
Number of pages13
JournalIndustrial and Engineering Chemistry Research
Issue number15
StatePublished - Apr 16 2014

All Science Journal Classification (ASJC) codes

  • General Chemistry
  • General Chemical Engineering
  • Industrial and Manufacturing Engineering


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