Mesoporous silica core–shell composite functionalized with polyelectrolytes for drug delivery

• Mesoporous SiPs with high surface area were synthesized for drug delivery system.
• The adsorbed amount of IBU is 1600 mg/g SiPs based on adsorption and TG method.
• The 2D hexagonal structure of the SiPs and the fractal dimension were determined.
• The IBU release is controllable by the formation of the core–shell structures.
• The kinetic models well describe to release mechanism.

Porous, spherical (d ≈ 400 nm) polyelectrolytes-coated silica particles (SiPs) with high surface area (1254 m2/g) have been synthesized for controlled release of ibuprofen (IBU) in aqueous dispersion. The zeta potential of the SiPs was negative (−77 mV) at pH 5.5, so the shells, as a positively charged polyethylenimine (PEI) and a negatively charged poly(sodium-4-styrenesulfonate) (PSS) bind through electrostatic interactions. The adsorbed amount of IBU is 1666 mg/g and 1618 mg/g SiPs based on adsorption method in aqueous media and thermogravimetric (TG) measurement, respectively. The SiPs was characterized by using low temperature N2 adsorption/desorption method. The well-ordered structure of SiPs and the fractal dimensions of the core–shell composites were determined by small angle X-ray scattering (SAXS) measurement. Finally the release properties of the IBU have been investigated; kinetic models were used to describe the release mechanism. The results of this study highlighted that the SiPs and the core–shell particles are well applicable as dissolution-enhancing systems for encapsulation of poorly soluble drugs.

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