RESEARCH

2. Nanomaterials for Controlled Drug Delivery Applications

The efficacy of a medicine is strongly affected by the mode of its delivery. For instance, whether a drug is administered orally or intravenously is very likely to determine its therapeutic effect. Therefore, novel drug delivery systems (DDS) may also lead to improvements in efficacy of pharmaceutical agents. With this in mind we are developing different types of DDS based on nanomaterials.

Cyclodextrin-alginate (CCal) Hydrogels for Compressive Drug Release

CCal hydrogels can encapsulate hydrophobic drug molecules in the cavities of cyclodextrin. Here, β-cyclodextrin covalently linked to the hydrogel network could be used to accommodate ondansetron (an antiemetic drug administered to avoid nausea in chemotherapy patients). Encapsulated ondansetron could then be released upon mechanical compression of the hydrogel. These materials are excellent candidates for ‘on demand’ DDS where a patient could self-administer certain therapeutic agents.

A patient self-administers a medicine by massaging a patch or implant containing CCal hydrogel impregnated with the relevant therapeutic agent.

Stimulus-free Drug Release by Silica Capsule Films

Hierarchically-structured silica capsule films were prepared using the layer-by-layer technique. The resulting films exhibit stepwise release of encapsulated guest materials implying their use for periodic DDS.

Silica capsule films. Mechanism of stepwise release(left): encapsulated material diffuses into the mesoporous capsule walls. The material contained in the wall diffuses to the exterior leaving the mesoporous walls vacant. Subsequent diffusion from the capsules’ interior replenishes the mesporous capsule walls. This process can be controlled based on porosity of the capsules’ walls and is suitable for stepwise cyclic release of materials.

Related Publications

T. G. Terentyeva, A. Matras, W. Van Rossom, J. P. Hill, Q. Ji and K. Ariga. “Bioactive Flake-Shell Capsules: Soft Silica Nanoparticles for Efficient Enzyme Immobilization” J. Mater. Chem. B (2013) 1, 3248–3256. [Link ]
Q. Ji, J. P. Hill and K. Ariga. “Shell Adjustable Hollow ‘Soft’ Silica Sphere as Support of Gold Nanoparticles” J. Mater. Chem. A (2013) 1, 3600–3606. [Link ]
H. Izawa, K. Kawakami, M. Sumita, Y. Tateyama, J. P Hill and K. Ariga. “β-Cyclodextrin-crosslinked Alginate Gel for Patient-controlled Drug Delivery Systems: Regulation of Host-guest Interactions with Mechanical Stimuli” J. Mater. Chem. B (2013) 1, 2155–2161. [Link ]
Q. Ji, T. Yamazaki, N. Hanagata, M. V. Lee, J. P. Hill and K. Ariga. “Silica-based Gene Reverse Transfection: Upright Nanosheet Network for Promoted DNA Delivery to Cell” Chem. Commun. (2012) 48, 8496–8498. [Link ]
Q. Ji, C. Guo, X. Yu, C. J. Ochs, J. P. Hill, F. Caruso and K. Ariga. “Flake-Shell Capsules with Adjustable Inorganic Structures” Small (2012) 8, 2345–2349. [Link ]
K. Kawakami, M. Ebara, H. Izawa, N. M. Sanchez-Ballester, J. P. Hill and K. Ariga. “Supramolecular Approaches for Drug Development” Curr. Med. Chem. (2012) 19, 2388–2398. [Link ]
K. Ariga, Y. M. Lvov, K. Kawakami, Q. Ji and J. P. Hill. “Layer-by-Layer Self-Assembled Shells for Drug Delivery” Adv. Drug Deliv. Rev. (2011) 63, 762–771. [Link ]
Q. Ji, S. Acharya, J. P. Hill, A. Vinu, S. B. Yoon, J.-S. Yu, K. Sakamoto and K. Ariga. "Hierarchic Nanostructure for Auto-Modulation of Material Release: Mesoporous Nanocompartment Films" Adv. Funct. Mater. (2009) 19, 1792–1799. [Link ]
Q. Ji, M. Miyahara, J. P. Hill, S. Acharya, A. Vinu, S. B. Yoon, J.-S. Yu, K. Sakamoto and K. Ariga. “Stimuli-Free Auto-Modulated Material Release from Mesoporous Nanocompartment Films” J. Am. Chem. Soc. (2008) 130, 2376–2377. [Link ]