Hydrophobically modified spherical MCM-41 as nanovalve system for controlled drug delivery

• Selective functionalization on spherical MCM-41.
• Comparison of hydrophobic and hydrophilic surfaces influence on drug delivery.
• Mesoporous surface functionalization influence on targeted drug delivery has been examined in detail.
• Importance of capping to the nanocontainers has been revealed through the delivery of trapped cargo with and without β-CD.

Spherical MCM-41 nanovalve having hydrophobically modified pore channels was synthesized via surfactant assisted sol–gel methodology and post modification process. The spherical MCM-41 has been tailored as a smart pH responsive drug carrier system by the insertion of N-3-(trimethoxysilyl)propyl aniline (TMSPA) at the pore opening before extracting the surfactant and further with phenyltrimethoxysilane (PTMS) to impart hydrophobicity on the inner surfaces of the pore channels. The surfactant extracted MCM-41 exhibits excellent textural properties such as very high specific surface area (1307 m2 g−1), pore diameter (24 Å) and pore volume (0.65 cm3 g−1). The transmission electron microscope (TEM) and scanning electron microscope (SEM) images of mesosphere reflect the highly uniform and mono-dispersed spherical morphology having a particle size of 500 nm. 5-Fluorouracil (5-Fu) and famotidine have been loaded into the hydrophobically modified channels followed with β-cyclodextrin (β-CD) as the gatekeeper to make the material as a pH responsive drug delivery system. The drug delivery has been carried out under in vitro condition at pH 4 and the amount of drug released from the nanovalve system was monitored by UV–Vis spectroscopy under regular intervals. The hydrophobically modified nanovalve was found to have delayed drug release of both 5-Fu and famotidine in comparison to the drug delivery from the nanovalve having unmodified pore channels synthesized from spherical MCM-41 under similar experimental conditions. The significance of functionalization as well as capping has been verified by the comparison of drug delivery behaviors among hydrophobically modified, unmodified, β-CD capped and uncapped nanocontainers.

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