Preparation of uniform microcapsules with silicone oil as continuous phase in a micro-dispersion process.

The State Key Laboratory of Chemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing, China.
Journal of Microencapsulation (Impact Factor: 1.88). 01/2008; 24(8):767-76. DOI: 10.1080/02652040701640560
Source: PubMed

ABSTRACT This paper presents an improved solvent evaporation method with silicone oil (PDMS) as the continuous phase for preparation of microcapsules to make more polymer solvents available. A microchannel device was used to produce emulsions instead of mechanical stirring to prepare the mono-dispersed microcapsules. Under the conditions of lower evaporation temperature and shorter evaporation time, uniform polyacrylonitrile (PAN) microcapsules containing Aliquat 336 (ALQ) have been successfully prepared. N,N-dimethylformamide (DMF) with lower evaporation ability was applied as the polymer solvent. The prepared microcapsules have rough surfaces and homogeneously internal structures. By changing the two-phase flow rate, the mean size of microcapsules can be easily controlled. When more ALQ was added in polymer solution, the loading ratio of microcapsules increased. The mass transfer performance and stability were determined by extraction of Cr (VI) ions from its aqueous solution. The mass transfer rate was fast enough. After three times of repeated extraction and stripping, the microcapsules kept almost the same extraction ability, which indicated that the microcapsules have very good stability.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Drug delivery via biodegradable microparticles benefits from both the protection of the encapsulated drug from hazardous conditions and the controlled release of the encapsulated drug, thereby reducing the administration frequency and improving patient compliance. Microsphere-size particle distribution is considered as being an important factor that affects the choice of the administration route and the drug-release rate. Significant research efforts have been directed towards the production of monodispersed "designer" particles. Amongst various techniques, some have been examined from lab-scale to industrial-scale. This review provides a global overview of monodispersed microparticle production methods and then focuses on recent processes being used to produce biodegradable microparticles applied in the pharmaceutical field. Further discussion about the choice of process according to the microparticle objectives of use is suggested.
    International Journal of Pharmaceutics 04/2011; 407(1-2):1-11. DOI:10.1016/j.ijpharm.2011.01.027 · 3.79 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Ionic liquids have recently attracted much attention as newly developed green solvents, but their high viscosity greatly limits their application. Immobilizing these ionic liquids using microencapsulation may solve this problem. In this study, a new extraction system for preparing microcapsules was developed in which a mixture of poly(dimethylsiloxane) and n-butyl acetate was used as the continuous phase, and polyacrylonitrile and ionic liquids were dissolved in N,N-dimethylformamide for the dispersed phase. The emulsion was prepared using a microfluidic device. The solidification of droplets was realized by extracting N,N-dimethylformamide from the dispersed phase to the continuous phase. Three different ionic liquids, [BMIM][PF6], [BMIM][BF4] and [HMIM][BF4], were successfully encapsulated with the average diameter of the microcapsules in the range of 200–350 μm. The properties of microcapsules – the surface structure, the loading ratio and the mean diameter – could be controlled by changing the operating conditions such as phase composition and the flow rate of two phases.
    Reactive and Functional Polymers 08/2008; 68(8-68):1260-1265. DOI:10.1016/j.reactfunctpolym.2008.06.006 · 2.82 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This paper reviews recent development and achievements in controllable preparation of nanoparticles, micron spherical and non-spherical particles, using microfluidics. A variety of synthesis strategies are presented and compared, including single-phase and multiphase microflows. The main structures of microfluidic devices and the fundamental principles of microflows for particle preparation are summarized and identified. The controllability of particle size, size distribution, crystal structure, morphology, physical and chemical properties, is examined in terms of the special features of microfluidic reactors. An outlook on opinions and predictions concerning the future development of powder technology with microfluidics is specially provided.
    Particuology 12/2011; 9(6). DOI:10.1016/j.partic.2011.06.004 · 1.65 Impact Factor