Guest‐Molecule‐Directed Assembly of Mesostructured Nanocomposite Polymer/Organoclay Hydrogels

Abstract

Given the urgent need for soft materials with high functional value, hydrogels based on the integrative assembly of organic polymers and nanoscale inorganic building blocks-so-called nanocomposite polymer hydrogels-offer a generic approach to swollen hybrid networks with tuneable and synergistic properties. Here, we report a new approach to assembling nanocomposite polymer hydrogels with multiple levels of structural complexity and enhanced functionality by using nanoscale integration of mesostructured inorganic building blocks capable of sequestering and releasing drugs (ibuprofen, aspirin, naproxen) and enzymes (glucose oxidase). The viscoelastic materials are produced by noncovalent crosslinking of poly(vinylpyrrolidone) in the presence of low amounts (1-5 wt%) of an exfoliated synthetic organoclay that undergoes in situ guest-molecule-directed self-assembly. The hydrogels can be moulded into shape-persistent, free-standing objects that are stable between pH values of 4 to 11 and self-heal when damaged. Signifi cantly, the mesostructured nanocomposite polymer hydrogels, which can be reversibly dried and reconstituted in the form of highly swollen materials, exhibit sustained drug release and can be recharged and reused. The results provide important guidelines for developing new multifunctional nanocomposite polymer hydrogels based on the concerted self-assembly of inorganic building blocks with mesostructured interiors.

Clay and Polymer-Based Composites Applied to Drug Release: A Scientific and Technological Prospection

“…This result mirrors those of Deleon et al (2012) that assessed a similar system in which ibuprofen release during the first few hours occurred due to desorption of the drug onto the surface of the composite, followed by slow release due to the ion exchange mechanism, a characteristic inherent to some clays (64). Martin et al (2011) and Campbell, Craig & Macnally (2010) produced sustained and retarded release hybrid systems for ibuprofen, respectively. Polyvinylpyrrolidone and organoclay nanocomposite released 80% of the ibuprofen content in 10 days, while organoclay completely released the drug after one day.…”

“…Release kinetics studies indicate that the composites exhibit Fickian behavior, and the most rapid diffusion was related to the drug dispersed in the pristine polymer (41). The shift in the release profile of ibuprofen can be attributed to the greater density of the polymeric matrix in the presence of clay and to restricted diffusion path by incorporation of the drug within the sheets or pores of the clay (67,97). In addition, the acidic drug has more affinity for the organoclays, resulting in a delay in its release.…”

“…Polyvinylpyrrolidone and organoclay nanocomposite released 80% of the ibuprofen content in 10 days, while organoclay completely released the drug after one day. (67). Compounds of poly-ε-caprolactone/fluoromic and poly-ε-caprolactone/montmorillonite increased the release time of 25% and 50% of ibuprofen by 230% and 133%, respectively, when compared to the polymeric system.…”

“…The main drugs carried in the articles analysed were non-steroidal anti-inflammatory drugs (46.1%) (24,39,40,(66)(67)(68), antimicrobial (25.6%) (21,34,65,69,74) and chemotherapeutic agents (10.3%) (13,14). This distribution can be explained by the adverse events associated with the use of these active principles, whether due to the reduction in gastric protection resulting from prolonged use of the anti-inflammatory drugs and analgesics, or to the intrinsic toxicity of chemotherapeutic agents and some antimicrobials associated with the risk of resistance (75,76).…”

Designed Nanostructures of Clay for Controlled Adsorption of Organic Compounds

“…13 110 The co-intercalation of a water-soluble polymer is another way to control the state of cationic dyes as well as the spatial distribution on smectites. [111][112][113][114][115][116] The isolation of [Ru(bpy) 3 ] 2+ has been achieved by the co-intercalation of photoinactive poly(vinyl pyrrolidone) (abbreviated as PVP). The [Ru(bpy) 3 ] 2+ -TSM-PVP intercalation compounds have been prepared with variable concentration of [Ru(bpy) 3 ] 2+ by cation exchange.…”