Microspheres and microcapsules: A survey of manufacturing techniques. Part 1: Suspension cross-linking
TL;DR: A methodological survey of preparation of microspheres and microcapsules by suspension cross-linking is presented in this paper, where the formation of small droplets of a polymer solution (or melt) in an immiscible liquid followed by hardening of these droplets by covalent crosslinking, are discussed.
Abstract: A methodological survey of preparation of microspheres and microcapsules by suspension cross-linking is presented. Thus, basic features of suspension cross-linking, i.e., the formation of small droplets of a polymer solution (or melt) in an immiscible liquid followed by hardening of these droplets by covalent cross-linking, are discussed. Typical microspherical and microcapsular products manufactured by suspension cross-linking of naturally occurring and preformed synthetic polymers, including agarose and cellulose beads, albumin microspheres and microcapsules, polystyrene beads and epoxy resin microcapsules, are described. Manufacturing parameters controlling microsphere/microcapsule characteristics are also briefly outlined.
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TL;DR: In this paper, the authors highlight the major reasons behind micro encapsulation, important techniques of microencapsulation and application of micro-encapsulated products in different areas of science and technology.
Abstract: Microencapsulation technology allows a compound to be encapsulated inside a tiny sphere known as microsphere/microcapsule, having an average diameter as small as 1 mm to several hundred micro meters. Many different active materials like drugs, enzymes, vitamins, pesticides, flavours and catalysts have been successfully encapsulated inside microballoons or microcapsules made from a variety of polymeric and non polymeric materials including poly(ethylene glycol)s, poly(methacrylate)s, poly(styrene)s, cellulose, poly(lactide)s, poly(lactide-co-glycolide)s, gelatin and acacia, etc. These microcapsules release their contents at appropriate time by using different release mechanisms, depending on the end use of encapsulated products. This technology has been used in several fields including pharmaceutical, agriculture, food, printing, cosmetic, textile and defence. In defence sector this technology has introduced the concept of self-healing composites as well as chemical decontaminating fabrics. This review paper highlights the major reasons behind microencapsulation, important techniques of microencapsulation and application of microencapsulated products in different areas of science and technology.Defence Science Journal, 2009, 59(1), pp.82-95, DOI:http://dx.doi.org/10.14429/dsj.59.1489
289 citations
TL;DR: A systematic description of various processes employed for microencapsulation of food additives is presented and basic features of microcapsular products, such as morphology, particle size, core/coat characteristics, and release behaviour, are highlighted.
Abstract: A systematic description of various processes employed for microencapsulation of food additives is presented. Microencapsulation methods covered include spray drying, fluidized bed coating, extrusion, solvent extraction, coacervation, cocrystallization, liposome formation and molecular inclusion. Basic features of microcapsular products, such as morphology, particle size, core/coat characteristics, and release behaviour, are also highlighted.
154 citations
TL;DR: A methodological survey of coacervation/phase separation techniques employed for the preparation of microspheres and microcapsules is presented in this article, where basic features of macromolecular co-acervation are discussed, and a classification of different co-cervation procedures (i.e., simple, complex, aqueous and nonaqueous) is provided.
Abstract: A methodological survey of coacervation/phase separation techniques employed for the preparation of microspheres and microcapsules is presented. Basic features of macromolecular coacervation are discussed, and a classification of different coacervation procedures (i.e., simple, complex, aqueous, and nonaqueous) is provided. Microsphere formation and microencapsulation techniques based on coacervation/phase separation of gelatin, gelatin-acacia, and ethylcellulose are described, and those of a wide range of other polysaccharide derivatives and synthetic polymers are tabulated. The dependence of microsphere/microcapsule characteristics on manufacturing parameters and performance evaluation of microspherical/microcapsular products are also discussed.
154 citations
TL;DR: A general review of preparative aspects of beaded polymer supports and gels (microbeads) is presented in this article, where basic features of manufacturing processes employed for beaded organic and inorganic polymers and gel are discussed.
133 citations
TL;DR: A methodological survey of microsphere formation and microencapsulation techniques based on solvent extraction/evaporation techniques is presented in this article, where the basic features of solvent extraction and solvent evaporation processes, including droplet formation, droplet/particle stabilization, and solvent removal, are outlined.
Abstract: A methodological survey of microsphere formation and microencapsulation techniques based on solvent extraction/evaporation techniques is presented. Thus, basic features of solvent extraction and solvent evaporation processes, including droplet formation, droplet/particle stabilization, and solvent removal, are outlined. Preparation of a wide range of microspherical and microcapsular products based on biodegradable polyesters, polysaccharides, and nonbiodegradable polymers are discussed. Dependence of microcapsule characteristics on manufacturing parameters, as well as performance evaluation of microspherical and microcapsular products, are also briefly covered.
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TL;DR: Shelf-life stability of lomustine and progesterone was reduced by incorporation in the microspheres, presumably due to their molecular dispersion in the poly(d,l-lactide).
300 citations
TL;DR: A method for producing alkali- and thermo-stable, insoluble spherical agar particles with very low adsorption capacity (tested with cytochrome C) is described.
213 citations
TL;DR: The synthesis and characterization of a novel parenteral drug carrier capable of area specific localization by magnetic means and release doxorubicin was chemically identical to the starting material.
211 citations
TL;DR: A method is described for preparation of spherical agarose or agar grains, to be used as bed material for chromatographic “sieving” of molecules and particles.
210 citations