The Synthesis of Alginate Microparticles and Nanoparticles

Abstract

Alginate is a natural polysaccharide that is widely used as a component of pharmaceuticals and in food industry. Alginate particles can be used for encapsulation of substances with the necessity of prolonged release. They can also provide appropriate microenvironment for cells. Here the methods of the synthesis of alginate beads, micro-and nanoparticles are reviewed with special attention to the calcium alginate ones. The results from publications that did not deal with alginate particles but, to our opinion, could be applied in this field are also included in order to give an outline for possible future research. The suggested applications of the particles are mentioned as well. The two main methods for the synthesis of calcium alginate particles are internal and external gelation, but the external gelation techniques can be themselves subdivided into several subtypes. Currently, a technique being able to produce alginate nanoparticles with any desirable size does not exist. We analyze the possibilities of employing aerosolization method for this purpose. The potentials to overcome the problem of burst release of the encapsulated substances by means of cyclodextrin inclusion complexes and employing additional crosslinking agents are also discussed. The clinical application of alginate nanoparticles is still limited because of the burst release of encapsulated drugs and the poor size control of the particles formed. Further research must concentrate on overcoming these problems and on topical application of alginate particles without entering bloodstream rather than on investigation of model drug release in vitro without taking the above-mentioned problems into account.

Alginate Nanoformulation: Influence of Process and Selected Variables

“…Emulsification/external gelation outputs micro/nanospheres consisting of a soft core and a rigid outer matrix [ 65 ]. Internal gelation technique on the other hand, depends on the release of cations from the inner core of alginate emulsion droplets [ 66 ]. Basically, a water-insoluble calcium salt, such as CaCO 3 , is mixed with alginate before emulsification ( Figure 3 ).…”

A Simple Non-Embedded Single Capillary Device for On-Demand Complex Emulsion Formation

“…Following the process of double droplet collection, the outer phase is supplemented with 0.5 mL acetic acid to initiate the gelation of alginate. The present approach for internal gelation is based on the methodology outlined in the work conducted by [26], with several modifications.…”

Electrosprayed mucoadhesive alginate-chitosan microcapsules for gastrointestinal delivery of probiotics

“…Applying chitosan coating has been reported to improve the protection abilities of alginate-based microcapsules (Chávarri et al, 2010;Cook et al, 2011;Nualkaekul et al, 2012). This can arise from the decreased pore size of the calcium alginate hydrogels after the application of coating (Pestovsky and Martínez-Antonio, 2019), with which the contact of the bacteria with the gastric fluid could be limited. Interestingly, incorporating resistant starch into the alginate matrix resulted in a statistically similar protection with chitosan coating throughout the digestion process.…”