Albumin-coated polymer particles

Emulsions and suspensions are colloidal dispersions of two or more immiscible phases in which one phase (disperse or internal phase) is dispersed as droplets or particles into another phase (continuous or dispersant phase). Therefore, various types of colloidal systems can be obtained. For example, oil/water and water /oil single emulsions can be prepared, as well as so-called multiple emulsions, which involve the preliminary emulsification of two phases (e.g., w/o or o/w), followed by secondary emulsification into a third phase leading to a three-phase mixture, such as w/o/w or o/w/o. Suspensions where a solid phase is dispersed into a liquid phase can also be obtained. In this case, solid particles can be (i) microspheres, for example, spherical particles composed of various natural and synthetic materials with diameters in the micrometer range solid lipid microspheres, albumin microspheres, polymer microspheres and (ii) capsules, for example, small, coated particles loaded with a solid, a liquid, a solid-liquid dispersion or solid-gas dispersion. Aerosols, where the internal phase is constituted by a solid or a liquid phase dispersed in air as a continuous phase, represent another type of colloidal system. 

Silica-base stationary phases have also been employed for enantiomeric separations in CEC [6,72-81]. In the initial work on chiral CEC, commercially available HPLC materials were utilized, including cyclodextrins [6,74,81] and protein-type selectors [73,75,80] such as human serum albumin [75] and ai-acid glycoprotein [73]. Fig. 4.9, for example, depicts the structure of a cyclodextrin-base stationary phase used in CEC and the separation of mephobarbital enantiomers by capillary LC and CEC in a capillary column packed with such a phase. The column operated in the CEC mode affords higher separation efficiency than in the capillary LC mode. Other enantiomeric selectors are also use in CEC, including the silica-linked or silica-coated macrocyclic antibiotics vancomycin [82,83] and teicoplanin [84], cyclodextrin-base polymer coated silicas [72,78], and weak anion-exchage type chiral phases [85]. Relatively high separation efficiency and excellent resolution for a variety of compounds have also been achieved using columns packed with naproxen-derived and Whelk-0 chiral stationary phases linked to 3 pm silica particles [79]. Fig. 4.10 shows the... 

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