Shifting from sustained to delayed drug delivery systems: Encapsulated mesoporous silica-chitosan grafted polylactic acid-based composite approach

Abstract

The current study demonstrates a desired drug delivery-controlled system with a wide range of release parameters. It illustrates the feasibility of carriers in the systems for extended and short drug release. Herein, mesoporous silica nanoparticles (MSNs) coated with chitosan (Cs) grafted polylactic acid (PLA) composite were fabricated by a sol-gel method in the form of micrometric porous particles (∼270 nm) with ζ-potential of −17.7 ± 1.7 mV and a specific surface area and total pore volume of 122700 cm2/g and 0.057 cm3/g, respectively. The prepared template of polymer-silica composite pores proved to be essential in the incorporation of Doxorubicin (Dox) drug molecules with adsorption capacity of 83.33 mg/g and encapsulation efficiency of 88 %. Dox was incorporated via the solvent diffusion method into the polymer-silica composites at suitable pH and concentration, resulting in solid drug dispersions. The silica-Cs-g-PLA composites showed greater effectiveness in the delayed release of the Dox with complete release after 10 days as compared to pristine MSNs and silica-Cs, which were completed after 12 h and 24 h, respectively. The drug release profiles were studied at different pH (2, 7, and 8), with maximum results obtained at pH 2. Both pristine MSNs and silica-Cs suffered from the burst effect, which was overcome by the grafting of PLA. The functionalized silica-Cs with PLA shows a significant change in the drug release properties from a sustained release process for pristine MSNs and silica-Cs to an enhanced delayed process for the silica-Cs-g-PLA composite, which makes this composite attractive for oral multi-particulate formulations of modified release.