Microencapsulation active ingredient

Sol-gel microencapsulation in silica particles shares the versatility of the sol-gel molecular encapsulation process, with further unique advantages. Sol-gel controlled release formulations are often more stable, potent and tolerable than currently available formulations. The benefits of microencapsulation can be customized to deliver the maximum set of benefits for each active ingredient. Overall, these new and stable combinations of active pharmaceutical ingredients (APIs) result in improved efficacy and usability. 

Microencapsulation can be used to provide a temporary barrier between a chemical species and its surrounding environment see also Section 14.3). This permits controlled (slow) release of the active agents following application. Depending on the product and the situation, an active ingredient such as a pesticide may need to be released slowly at low concentration, or slowly at high concentrations. Such controlled release can both reduce the number of crop applications that are required and also help prevent over use and subsequent run-off. The barrier can be provided by a polymer film, in the case of suspensions [867], or a liquid membrane, in the case of single or multiple emulsions [865], Microemulsions have also been used [234,865],... 

Abstract. Microencapsulation is widely use in industry but remains relatively unknown from the public. The reason is that microcapsules are not an end-product, but generally a technique to overcome process limitations. Microencapsulation allows immobilization, protection, release and functionalisation of active ingredients. Despite the high diversity of methods, this paper proposes a classification and description of the main technologies to produce microcapsules. 

The widely used organophosphate Insecticide methyl parathlon was the first material to be formulated as a microencapsulated pesticide. This formulation, sold under the tradename PENNCAP-M Insecticide (a registered trademark of Pennwalt Corporation), consists of nylon-type microcapsules which contain the active Ingredient. The capsules are suspended In water and typically have an average particle size of approximately 25 microns (fifty percent by weight of the capsules have a particle size of 25 microns or more). Upon application by conventional spray equipment the water evaporates, and the active Ingredient Is slowly released over an extended period of time. 

Microencapsulation is a process in which a pure active ingredient or a mixture of ingredients is coated with or entrapped within a protecting material or system (see also Chapter 24). As a result, useful and otherwise unusual properties may be conferred to the microencapsulated ingredient(s), or unusefiil properties may be eliminated from the original ingredient(s) (Shahidi and Han 1993). The particle size of microcapsules formed by either encapsulation or entrapment can vary between... 

Rapid expansion of supercritical solutions (RESS) processing is used to prepare microspheres. Microencapsulation takes place when a pressurized supercritical solvent containing the shell material and the active ingredient is released through a small nozzle the abrupt pressure drop causes the desolvation of the shell material and the formation of a coating layer around the active ingredient (74). A prerequisite for this technology is that the compounds effectively dissolve in the SCF, which limits its application. 

In the case of probiotic microencapsulation, particles were broken down in serial dilutions with warm dilutant (peptone water, sodium citrate solution, and sodium chloride solution), for the quantification of viable cells in the system. For this specific active ingredient, as they are live microorganisms, heating cannot be too high so as to damage or kill the bacteria. Therefore, it is necessary to choose a matrix that does not have a high melting point. 

The sol-gel microencapsulation in silica-based materials is an emerging and powerful nanochem-istry technology in which the active ingredients are protected (stabilized) in silica-based particles. ... 

An analysis of scientific articles and patents shows numerous possibilities of adding microencapsulated active ingredients into construction materials, such as cement, lime, concrete, mortar, artificial marble, sealants, paints and other coatings, and functionalized textiles. 

Zuidam, N.J. Shimoni, E. Overview of microencapsulates for use in food products or processes and methods to make them. In Zuidam, N.J., Nedovic, V.A., eds. Encapsulation Technologies for Food Active Ingredients and Food Processing. Springer Dordrecht, the Netherlands 2009, pp. 3-31. 

The formulations of agrochemicals cover a wide range of systems which range from simple aqueous solutions (for water-soluble actives) and self-emulsifiable oils to disperse systems of suspensions, emulsions and microemulsions. More complex formulations such as multiple emulsions and suspoemulsions (mixtures of suspensions and emulsions) are also applied in some cases. Microencapsulation of active ingredients for controlled and sustained release represents a more sophisticated approach to the formulation of agrochemicals. Solid formulations of wettable powders, grains, granules and tablets are also used in many applications. 

One may list a large number of surface chemical phenomena that are crucial in the preparation of more complex systems such as multiple emulsions and microcapsules. In the first case, the formulation is a complex system of an emulsion in an emulsion , with the most common being a water-in-oil-in-water (W/O/W) multiple emulsion, which requires the preparation of a stable W/O emulsion that is further emulsified into an aqueous solution of another surfactant to produce the final system. Microencapsulation is a process whereby the active ingredient is surrounded by a polymer shell that allows the controlled and slow release of the active. The most common procedure for encapsulation is interfacial polymerization, whereby two monomers are allowed to react at the interface (by condensation) to produce the... 

In relation to detergent ingredients, different microencapsulation technologies are often used for fragrances and flavors. Coacervation and spray drying are mentioned in various patent applications (see example of coacervation in Ref 139 and spray drying in Ref 140). In the case of bleach active substances, microencapsulation of TAED using a polycondensation process is described in Ref 141, and a coacervation process for the encapsulation of PAP is mentioned in Ref 142. In both cases, the use in liquid applications is intended. 

Microencapsulation for protective purposes is equally important as the controlled release uses, as microcapsules may prevent the possible premature loss of an active ingredients, which is reflected in a decline of its activity. 

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