Papers by Keyword: Drug Delivery System

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Authors: Yasuhiko Tabata
Abstract: A new therapeutic trial based on the self-healing potential of cells to naturally induce tissue regeneration, has been recently noted. To realize this regenerative medical therapy, it is highly required to efficiently combine cells with their local environment which basically allows cells to survive and biologically function in vivo through the essential interaction. Tissue engineering is a biomedical technology or methodology to create the local environment which promotes the proliferation and differentiation of cells to induce tissue regeneration. There are some cases where tissue regeneration can be induced only by supplying a cell scaffold of biomaterials. Drug delivery system (DDS) with biomaterials enhanced the in vivo biological activities of un-stable growth factor and gene for cell-induced tissue regeneration. The controlled release technology enabled growth factors to achieve the regeneration of various tissues experimentally and clinically. The DDS technology also augmented the biological functions of plasmid DNA and small interference RNA. The cells genetically engineered by the DDS gene system showed an enhanced therapeutic efficacy in cell-based tissue regeneration (cell-gene hybrid therapy). By making use of DDS technology, it is possible to suppress the deterioration and proceeding of chronic fibrotic diseases based on the self-healing potential inherently equipped in the living body. This paper emphasizes significance of biomaterials in tissue engineering for regenerative medical therapy.
Authors: S. Josse, C. Faucheux, A. Soueidan, G. Grimandi, D. Massiot, B. Alonso, Pascal Janvier, S Laïb, Jerome Guicheux, B. Bujoli, Jean Michel Bouler
Abstract: One type of potent aminobisphosphonate (Zoledronate) has been chemically associated onto b-tricalcium phosphate [b-TCP] and calcium deficients apatite [CDA]. Two different association modes have been observed, according to the nature of the Calcium Phosphate [CaP] support and/or the initial concentration of the Zoledronate solution. b-TCP appears to promote Zoledronate-containing crystals formation. On the other hand, at concentrations < 0.05 mol.L-1 CDA seems to undergo chemisorption of the drug through a surface adsorption process, due to PO3 for PO4 exchange, which is well described by Freundlich equations. At concentrations > 0.05 mol.L-1, crystalline needles of a Zoledronate complex form onto the CDA surface. The ability of CDA to release Zoledronate, resulting in the inhibition of osteoclastic activity, was shown using a specific in vitro bone resorption model.
Authors: Yun Suk Jo, Do-Kyung Kim, Young Keun Jeong, Kyung Ja Kim, Mamoun Muhammed
Abstract: A novel approach to load a hydrophilic bovine serum albumin (BSA) into the drug carriers was proposed in terms of thermosensitive dual-shell structures which were fabricated with poly(N-isopropylacrylamide), poly(lactide) and Au nanoparticles. Spherically well-defined dualshell structures were constructed by a modified-double-emulsion method (MDEM). The lower critical solubility temperature of the structures was shifted to 36.4 °C which was confirmed by UVVis spectroscopy.
Authors: Feng Chai, Jean Christophe Hornez, N. Blanchemain, C. Neut, M. Descamps, H.F. Hildebrand
Abstract: The advantages of local antibiotic administration - high local levels with low systemic toxicity - are nowadays recognized as an efficient way for anti-infection therapies consecutive to the orthopaedic implant surgery. Aimed at assessing the feasibility of using Hydroxyapatite as drugdelivery carrier in addition to its well-known bone reconstruction bioactivity, a pure HA ceramic with specific internal pore size and porosities was under our investigation. The antibiotic release and antibacterial effect were determined by UV spectrophotometry and disk agar diffusion assays after impregnation with different antibiotics and their release in different solvents. No differences were found after the ATB impregnation under normal pressure or under vacuum conditions. The influences of impregnation time on the duration of the ATB release and on the antibacterial efficiency were more evident for Vancomycin than for Ciprofloxacin and Gentamycin. In all cases, the ATBs penetrated micro-porous and meso-porous HA samples and showed significantly stronger and longer anti-bacterial effects than dense HA samples. The ATBs releases in PBS were relatively slower and the antibacterial effectiveness subsequently prolonged with respect to those in human plasma. All tested HA samples with or without ATB impregnation exhibited very good biocompatibility as shown by cell proliferation tests. It revealed a promising perspective for further improving the antibacterial efficiency by other surface functionalization methods for achieving a controllable drug delivery with antibiotic loaded HA.
Authors: Toru Tonegawa, Toshiyuki Ikoma, Tomohiko Yoshioka, Kazuo Shinozaki, Nobutaka Hanagata, M. Tanaka
Abstract: Insulin delivery carriers using low crystalline porous zinc hydroxyapatite (ZnHAp) microparticles with different crystal sizes and novel formulation method of poly (lactic acid) (PLA) have been developed to achieve the sustained-release of insulin. The adsorption isotherm curves of insulin dissolved into acetic acid of pH4.5 onto ZnHAp nanocrystals show non-Langmuir type due to the dissolution of the ZnHAp microparticles; the adsorption amounts were increased with the increase of crystalline sizes. The PLA formulation, coating the outer layer of microparticles, showed the apparent reduction of initial burst for insulin. The amounts of initial release of insulin decreased with the increase of crystalline sizes of ZnHAp, which could be attributed to the different meso-porous structure depending on its crystal sizes.
Authors: Shen Guo Wang, Qing Cai, Jian Zhong Bei, Wei Yun Shi, Li Xin Xie
Abstract: In the article a kind biodegradable drug carrier (glycolide-co-lactide-co-caprolactone) tricomponent copolymer (PGLC) was synthesized by ring opening copolymerization of glycolide (GA), lactide (LA) and ε-caprolactone (CL), and was used to manufacture an implantable drug preparation---Cyclosporine-PGLC drug delivery system (Cs-PGLC DDS).The Cs could slowly release from the Cs-PGLC DDS near linearly and last for a long time in vitro. A clinically significant Cs concentration in the cornea and anterior chamber could be achieved by implanting the Cs-PGLC DDS in anterior chamber. It was demonstrated that the Cs-PGLC DDS is a long-effective intraocular immunosuppressive agent for remaining corneal allograft clear and significantly prolong its survival time.
Authors: Mamoru Aizawa, Toshiki Ohno, N. Kanomata, K. Yano, M. Emoto
Authors: Jean Christophe Hornez, Feng Chai, N. Blanchemain, A. Lefèvre, M. Descamps, H.F. Hildebrand
Abstract: Calcium phosphate compounds, in particular HA and β-TCP, are the principal synthetic materials used for bone substitutes. To assess the feasibility for further grafting of drug delivery systems, a pure HA was elaborated with specific internal material porosities and then tested on its biological effectiveness. The cell viability tests with L132 cells confirmed the excellent cytocompatibility of HA and the graphite powder. MC3T3-E1 osteoblasts were grown on HA conditioned with culture medium and FCS for 2h. All HA samples produced a higher proliferation and vitality rates than the TCPS controls; the micro-porous HA inducing the highest cell growth near 150%. The macro/meso-porous HA is easily colonized by MC3T3-E1 osteoblasts As to the cell morphology, no significant differences are observed between control cells and those grown on the HA samples. Cytochemical staining of osteoblasts revealed a well developed cytoskeleton with strong stress fibres oriented in the cells in their longitudinal direction. Labelling of the focal adhesion contacts with anti-vinculin showed a less developed adhesion process in the cells on the different HA substrates, which may explain the above mentioned increase of proliferation.
Authors: Laetitia Obadia, Gilles Amador, G. Daculsi, Jean Michel Bouler
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