Papers by Keyword: PLGA

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Authors: Akhtar Jahan Siddiqa, Koel Chaudhury, Basudam Adhikari
Abstract: The present work focuses on the development of biodegradable PLGA nanoparticles (NPs) for controlled release of a breast cancer drug, letrozole. NPs of different drug-polymer ratio formulations (F1, F2, F3, F4) were fabricated using solvent evaporation technique. Physico-chemical characteristics of these NPs were assessed using dynamic light scattering (DLS) spectrophotometer. In-vitro drug release study was carried out over an extended period of 30 days at 37 °C in simulated physiological fluid. To evaluate the release kinetics, data was fitted to different models. NPs with various sizes and size distributions were obtained by altering the drug-polymer ratio. Zeta potential of PLGA and drug loaded NPs were found to be-29.4± 1.3 mV and-21.0±0.6 mV, respectively. The release kinetics of the drug from NPs was in good agreement with Korsmeyer-Peppas model, ensuring controlled release of the drug from the NPs. In-vitro release studies showed high correlation coefficient (R2 = 0.90) for formulation F2 and F3 up to 30 days. It is concluded that NPs with F2 and F3 formulations provide a controlled release of the incorporated drug and, therefore, hold promise to be investigated further in detail.
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Authors: Jian Fei Xie, Chun Yan Li, Shu Han Hong, Yu Rong Yan
Abstract: In order to study in vitro release behavior of hydrophilic drugs in polymer nanofibers and establish a fast characterization method, tetracycline hydrochloride-loaded poly (lacticacid-co-glycolic acid) nanofiber mats with varied tetracycline hydrochloride contents and different lacticacid to glycolic ratios in PLGA were preparied by electrospinning. Accroding to Chinese Pharmacopoeia, a basic and an improved test devices and processes were compared and their validity were commented by using an UV-visible spectrophotometer method. Results showed that the improved method can be used to estimate in vitro drug release behavior of drug-loaded mats and the results was better than the basic method. When temperature affected cumulative release ratio under controlled error, flotation method can replace the centrifugation method during the first stage of drug release testing process. Parallel experiments were carried out and results indicated that nanofibres on different part of mats had a relative stable result and repeat experimental error was kept below 4%.
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Authors: J. Schäfer, Johannes Sitterberg, C. Ehrhardt, M.N.V. Ravi Kumar, Udo Bakowsky
Abstract: The preparation and charactersiation of novel lipid coated PLGA nanoparticles was investigated in the presented study. The size of the pure nanoparticles could be adjusted in dependence on the stabilizer content. The supported lipid bilayer surrounding the nanoparticles was formed by the liposome spreading technique. The Lipid- coated nanoparticles were characterised using Photon Correlation Spectroscopy (PCS) and atomic force microscopy (AFM) investigations. The bioadhesive properties was proofed in a cell culture model.
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Authors: Gaku Tamazawa, Atsuo Ito, Takahiro Miyai, Tomonori Matsuno, Yu Sogo, Tazuko Satoh
Abstract: A composite of co-polymer of lactic and glycolic acids (PLGA) loaded with gatifloxacine (GFLX), an antibiotics, and a β-tricalcium phosphate (βTCP) porous ceramic body was prepared by a solvent-free process in which no toxic solvent was used. The GFLX-loaded PLGA released GFLX for 8 weeks in Hanks’ balanced solution. The inhibitory zone diameter (26.25±0.95 mm) for GFLX-containing PLGA disk against S. milleri was significantly larger than 18 mm, and comparable to that (24.88±1.6 mm) for the KB paper disk containing 5 μg of GFLX/disk. This means that the GFLX-containing PLGA has the clinical efficacy. The molten PLGA containing GFLX was successfully loaded in the pores and on the surface of the porous βTCP ceramic at 120 °C at a reduced pressure of 0.02 MPa. The composite of GFLX-loaded porous βTCP ceramic would be promising for treating osteomyelitis.
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Authors: Toshiki Itoh, Seiji Ban, T. Watanabe, Shozo Tsuruta, Takahiro Kawai, Hiroshi Nakamura
Abstract: It is well known that bone morphogenetic protein (BMP) induces bone formation and requires for carriers. Poly-lactic acid / poly-glycolic acid (PLGA) is frequently used as the carriers of BMP. We developed a biodegradable composite PLGA membrane, which was containing oriented needle-like apatite with BMP. The composite membranes were implanted into the thigh muscle pouch of 3-week-old-mice. At 3 weeks after implantation, the implanted area was observed by optical microscopy. The composite membrane containing oriented needle-like apatite with BMP induced new bone formation. It seems that this composite membrane might be a scaffold of BMP and promoting the healing of bone defects.
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Authors: Aldo Roberto Boccaccini, J.J. Blaker, V. Maquet, R. Jerome, S. Blacher, Judith A. Roether
Abstract: Porous bioresorbable and bioactive composite materials designed for applications as scaffolds in tissue engineering are discussed. The systems fabricated by thermally induced phase separation method and based on poly(D,L-lactide) (PDLLA) or poly(lactic acid-co-glycolic acid) (PLGA) with additions of bioactive glass particles (45S5 Bioglass®) are described in detail. The scaffolds exhibit a well-defined, oriented and interconnected porosity. The porosity structure of foams with and without Bioglass® was characterised by scanning electron microscopy. The in vitro bioactivity and degradability of the composite foams were investigated in contact with phosphate buffer saline (PBS) and simulated body fluid (SBF). High chemical reactivity of scaffolds in SBF, which leads to the prompt formation of bonelike hydroxyapatite crystals on the material surfaces, indicates an enhanced bioactive character of the composites and therefore their potential for use as bone tissue engineering scaffolds.
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Authors: R.P. Félix Lanao, J.W.M. Hoekstra, Joop G.C. Wolke, Sander C.G. Leeuwenburgh, A.S. Plachokova, O.C. Boerman, Jeroen J.J.P. van den Beucken, John A. Jansen
Abstract: Periodontitis is one of the most common inflammatory diseases, which can lead to early tooth loss. The conventional treatment of periodontitis is to arrest the disease progression. Most reconstructive procedures involve application of bone substitutes, barrier membranes or a combination of both into the bony defects. Calcium phosphate cements (CPCs) are the predominant type of bone substitute material used for reasons of injectability and hence perfect filling potential for bone defects. Recently, injectable apatitic CPCs demonstrated to be more rapidly degradable when combined with poly (lactic-co-glycolic) acid (PLGA) microspheres. Further, PLGA microspheres can be used as a delivery vehicle for growth factors. In this study, the performance of injectable CPCs as a bone substitute material for alveolar bone defects created in Beagle dogs was evaluated. Four CPC-formulations were generated by incorporating hollow or dense PLGA microspheres, either or not loaded with the growth factors (platelet derived growth factor (PDGF) and insulin-like growth factor (IGF). Implantation period was 8 weeks. Bone formation was based on histological and histomorphometrical evaluation. The results demonstrated that filling alveolar bone defects with CPC-dense PLGA revealed significant more bone formation compared to CPC-hollow PLGA either or not loaded with IGF and PDGF. In summary, we conclude that injectable CPC-dense PLGA composites proved to be the most suitable material for a potential use as off the shelf material due to its good biocompatibility, enhanced degradability and subsequent bone formation.
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Authors: J. Miguel Oliveira, Takahiro Kawai, M.A. Lopes, Chikara Ohtsuki, José D. Santos, A. Afonso
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Authors: Yang Gao, Xiao Peng Wang, Tian Ning Chen
Abstract: To eliminate the release-delayed phenomenon of macromolecular drug delivery system at the early stage, biodegradable implantable drug delivery system with micro-porous structure was designed by Bio-MEMS technology in this paper. Water absorption and degradation characters of polylactic acid - polyglycolic acid (PLGA) material with different monomer ratio were studied. Drug release model was built by mass transfer equation and the Finite Element Method. Influencing factors about the cumulative amount of release drug were analyzed. And the results suggest that with more ratio of polylactic acid(PLA), PLGA would have more greater amount of water absorbed as well as a longer degradation time. Better linearity of cumulative amount of release drug would be achieved by reducing the diameter and number of micro-porous.
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Authors: Girlie M. Munar, Melvin L. Munar, Kanji Tsuru, Ishikawa Kunio
Abstract: Carbonate apatite (CO3Ap) foam with interconnecting porous structure is a potential candidate as bone substitute material owing to its similarity to the cancellous bone with respect to composition, morphology and osteoclastic degradation. However, it is brittle and difficult to handle. This is thought to be caused by no organic material in the CO3Ap foam. The aim of this study is to reinforce the CO3Ap foam with poly (DL-lactide-co-glycolide) (PLGA). Immersion and vacuum infiltration methods were compared as reinforcing methods. Compressive strength of unreinforced CO3Ap foam, (12.0 ± 4.9 kPa) increased after PLGA reinforcement by immersion (187.6 ± 57.6 kPa) or by vacuum infiltration (407 ± 111.4 kPa). Scanning electron microscopy (SEM) showed the preservation of full interconnecting porous structure of CO3Ap foam after PLGA reinforcement using immersion or vacuum infiltration. Interface between the PLGA and CO3Ap foam, however revealed that no gap was found between the PLGA and CO3Ap foam interface when vacuum was used to reinforce the PLGA whereas a gap was found when simple immersion was used. Strong interface between PLGA and CO3Ap foam is therefore thought to be the key for higher compressive strength. In conclusion, vacuum infiltration is a more efficient method to reinforce the CO3Ap foam with PLGA for improving the mechanical strength without sacrificing the cancellous bone-type morphology.
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