Magnetic‐targeted pH‐responsive drug delivery system via layer‐by‐layer self‐assembly of polyelectrolytes onto drug‐containing emulsion droplets and its controlled release

Abstract

Novel magnetic‐targeted pH‐responsive drug delivery system have been designed by the layer‐by‐layer self‐ assembly of the polyelectrolytes (oligochitosan as the polycation and sodium alginate as the polyanion) via the electrostatic interaction with the oil‐in‐water type hybrid emulsion droplets containing the superparamagnetic ferroferric oxide nanoparticles and drug molecules [dipyridamole (DIP)] as cores. Here the drug molecules were directly encapsulated into the interior of droplets without etching the templates and refilling with the desired guest molecules. The drug‐delivery system showed high encapsulation efficiency of drugs and drug‐loading capacity. The cumulative release ratio of dipyridamole from the oligochitosan/sodium alginate multilayer‐encapsulated magnetic hybrid emulsion droplets (DIP/Fe3O4‐OA/OA)@(OCS/SAL)4 was up to almost 100% after 31 h at pH 1.8. However, the cumulative release ratio was only 3.3% at pH 7.4 even after 48 h. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

Technology-driven layer-by-layer assembly of nanofilms

“…Magnets, rather than electric currents, can be used to assemble LbL films on sensitive particulate templates, such as emulsions (74), or small templates difficult to pellet through centrifugation, such as sub-10-nm iron oxide nanoparticles (19). Template particles containing magnetic nanoparticles can be separated from the polymer solution using a magnet, which, similar to the filtration method, allows for nearly 100% of the particles to be recovered in a centrifugationfree LbL assembly process (75).…”

pH‐Responsive Drug‐Delivery Systems

“…This synthetic strategy was also extended to fabricate monodisperse (concentric-NaYF 4 :Yb/Er/ Gd@SiO 2 )@polyacrylic acid core-double shell nanocomposite. Mu et al [97] reported a magnetically targeted pH-responsive drug-delivery system prepared by layer-by-layer self-assembly of the polyelectrolytes (oligochitosan as the polycation and sodium alginate as the polyanion) through an electrostatic interaction with oil-in-water-type hybrid emulsion droplets that contained Fe 3 O 4 nanoparticles and dipyridamole drug as the cores, and the cumulative release of dipyridamole from the drug-delivery system was nearly 100 % after 31 h at pH 1.8; in contrast, the cumulative drug release was only 3.3 % at pH 7.4 even after 48 h.…”

Encapsulation of drug microparticles with self‐assembled Fe3O4/alginate hybrid multilayers for targeted controlled release

“…Then the magnetic nanoparticles and polyelectrolyte were alternately deposited for another two times onto the MDIP @ (Fe 3 O 4 /SAL) 1 Controlled release of MDIP @ (Fe 3 O 4 /SAL) 3 The controlled release of MDIP @ (SAL/Fe 3 O 4 ) 3 was conducted as follows. 24 3 ] was transferred into dialysis tubes with a molecular weight cutoff of 14,000 and immersed into 90 mL buffer solution under two pH values (pH 1.8 and 7.4) at 25 C, respectively. Each aliquot (5.0 mL) of the solutions were taken out after a time intervals.…”

“…The magnetic hybrid encapsulations with pH-responsive polyelectrolyte shells and higher drug-loading were directly used as drug releaser without removing the templates and refilling with the desired molecules. 24 Aimed at the excellent drug-loading and controlled releasing performance, there were several works reported in which the model-drug microparticles or microcrystals were encapsulated as the cores with the polyelectrolytes through the LbL assembly technique. Caruso et al encapsulated two uncharged microcrystalline substances, pyrene (PYR) and fluorescein diacetate (FDA), by exposure to an alternating sequence of the cationic and anionic polyelectrolytes, followed by being treated with various amphiphilic substances to render the water-dispersibility.…”