Grafting of thermo-responsive polymer inside mesoporous silica with large pore size using ATRP and investigation of its use in drug release

Abstract

The design of a delivery system was reported based on stimuli-responsive poly(N-isopropylacrylamide) (PNIPA) inside a mesostructured cellular foam (MCF) via atom transfer radical polymerization (ATRP), and the control of drug release in response to the environmental temperature was investigated. The successful synthesis of PNIPA inside the MCF was confirmed by Fourier transform infrared (FT-IR), transmission electron microscopy (TEM) and nitrogen adsorption/desorption measurements. Control of drug release through the porous network was performed by measuring the uptake and release of ibuprofen (IBU). The delivery system of MCF-PNIPA demonstrated a high IBU storage capacity of 58 wt% (IBU/silica), which is much higher than that reported for functional SBA-15 (37 wt%). The multilayer polymers inside the pores of the MCF were considered to form an internal cavity for drug molecules in addition to responding to changes in external temperature.

Multifunctional Nanocomposites Based on Mesoporous Silica: Potential Applications in Biomedicine

“…It is important to note that this release mechanism is clearly different from those previously reported (Zhou et al, 2007;Zhu et al, 2007), since the major release rate was observed below the LCST, rather than above it (a negative thermosensitive release profile was observed). However, similar results were presented by You et al (You et al, 2008), who studied the release of fluorescein as a function of the temperature from micro to mesoporous silica nanoparticle (MSN)/P(N-iPAAm) composites and obtained a greater release rate at 25 ºC, below LCST (Figure 17).…”

“…However, studies on ordered mesoporous silica-thermoresponsive P(N-iPAAm) hybrids for use as DDS are few. To the best of our knowledge, only a small number of papers concerning a responsive-carrier-system-based mesoporous silica and P(N-iPAAm) for use in the drug delivery area has been reported up to the present (Zhou et al 2007;Yang et al, 2008;You et al, 2008;Liu et al, 2009;Zhu, et al, 2009;Sousa et al, 2010). Chang and co-authors (Chang et al, 2004) report the systematic application of the ordered mesoporous materials to smart controlled drug release using the thermoresponsive P(NiPAAm) hybrid mesoporous structures.…”

“…Although a large amount of drug may be squeezed out of the polymer above the LCST, the amount released into the media did not show a peak, because diffusion of the drug through the porous channels is the limiting mechanism to control the drug release, rather than the phase behavior of the P(N-iPAAm). In this same sense, Zhou et al investigated a system based on stimulus-responsive P(NiPAAm) inside a mesostructured cellular foam (MCF-PNIPA) as a device for drug delivery (Zhou et al, 2007). Ibuprofen (IBU) was loaded in MCF-PNIPA samples at 45 ºC during 48 h. Drug release studies were performed by soaking samples in a solution with pH maintained at 7.4 and stepwise changing the temperature between 10 and 60 ºC.…”

Mesoporous silica nanoparticles for stimuli-responsive controlled drug delivery: advances, challenges, and outlook

“…Other researchers also investigated the PNIPAM-based thermo-responsive DDS using MSN as the drug container. [130][131][132][133][134][135][136] This new core-shell thermo-responsive nanocarrier showed promising potential in controlled drug/gene delivery.…”

Development of a Prolonged-Release Drug Delivery System with Magnolol Loaded in Amino-Functionalized Mesoporous Silica

“…The bioavailability of the silica particles is influenced by characteristics like surface area, zeta-potential, hydrophilicity, functional groups on surface, affinity and selectivity. By altering such particle properties, drug carriers become more effective [28][29][30][31].…”