Smart Carriers for Controlled Drug Delivery: Thermosensitive Polymers Embedded in Ordered Mesoporous Carbon.

ABSTRACT

An efficient drug delivery system was introduced. The carrier was synthesized by combination of an ordered mesoporous carbon (CMK3) and a thermosensitive polymer, poly(N-isopropylacrylamide), known as PNIPAAm. The polymers with 2 different chain lengths (PNIPAAm-100n and PNIPAAm-400n) were synthesized and each of the polymers was embedded in CMK3 to form composite materials. Nitrogen adsorption isotherm and scanning electron microscopy of the samples showed a uniform embedding of PNIPAAm-100n but a nonuniform embedding of PNIPAAm-400n. The latter observation is attributed to large intramolecular interactions of PNIPAAm-400n and their aggregation on the external surface of the porous structure. Doxorubicin was used as the model drug and was loaded onto the samples. The ultimate loading capacities for the polymer-embedded samples were reduced. However, the loading rates and the release capacities were significantly improved. Thermosensitivity of the polymer was introduced as the governing drug release mechanism; regardless of the polymer chain length, drug release at 37°C was significantly higher than 4°C. Cytotoxicity results confirmed materials' biocompatibility for future biological tests. It is clearly shown that the properly synthesized composite of ordered mesoporous carbon and thermosensitive polymer can be used as an efficient carrier for drug loading and release experiments. The loading and release profiles can be controlled by tailoring the polymer chain length.