Mechanical testing
C M Langton, C F Njeh in The Physical Measurement of Bone, 2016
Another mode of sterilization is the use of ionizing radiation. The effects of radiation on the biomechanical properties of bone remain a matter of debate [151–157]. Zhang et al [157] found that there was no significant difference in mechanical or material properties of the iliac crest wedges exposed to dosages of 2–2.5 kGy when compared with the non-irradiated wedges. They suggested that 2–2.5 kGy is an acceptable dose for gamma irradiation sterilization of the iliac crest. Komender [151] found that the bending, compression and torsion strength of human femoral diaphysis to be compromised significantly when irradiated with doses of 60 kGy but not when doses of 30 kGy were used. Another study by Hamer et al [156] showed a significant reduction (64%) in bending strength of human femur after irradiation with 28 kGy. Currey et al [155] found that Young’s modulus was unchanged by any level of radiation (17, 29.5 and 94.7 kGy). However, radiation significantly reduced bending strength, work to fracture and impact energy absorption. The study of Currey et al [155] and those of other have consistently demonstrated that the reduction in strength is dependent on the dose [155, 156]. Radiation, even at relatively low doses, makes the bone more brittle and thereby reduces its energy-absorbing capacity. To limit the impact of radiation on the mechanical properties of bone, low levels of radiation sufficient to produce bacterial safety should be used in conjunction with biological tests.
Regulatory Issues in Drug Delivery to the Eye
Glenn J. Jaffe, Paul Ashton, P. Andrew Pearson in Intraocular Drug Delivery, 2006
Filling the product into its container and sterilizing it through autoclaving is known as terminal sterilization; or sterilization of the final product. While this may appear to be a better alternative because all organisms present in the final product are destroyed, the difficulty with terminal sterilization is that many drug substances cannot stand up to the heat required for terminal sterilization. Even when the product can withstand the autoclave environment, the materials that are used to produce the bottles, such as low-density polyethylene, cannot withstand autoclaving. Materials that can withstand autoclaving produce a bottle that is so rugged as to require a greater force than many older patients can apply to deliver the product through the tip. The pharmaceutical industry is in search of a material that is rugged enough to withstand autoclaving while being soft enough that a consumer is able to squeeze the final bottle and dispense one drop into their eye. Other forms of terminal sterilization include e-beam and gamma radiation. Although these too impose their own constraints on the drug and packaging system, over the last 20 years they have become increasingly popular.
Animal Models of Meniscal Repair
Yuehuei H. An, Richard J. Friedman in Animal Models in Orthopaedic Research, 2020
Allograft menisci comies from a different animal of the same species. Allografts are the state of art to replace a complete meniscus. Both human and animal trials have proven that transplantation of a meniscus is technically possible.59,70,77,78,83,92 Theoretically, this method provides for a replacement meniscus that is as much identical to the original one as it possibly can be. Its disadvantages have been mentioned before and include the danger of disease transmission, the limited availability and storage time and problems of sterilization. In theory, allograft menisci could give rise to immunological reactions. Although the meniscus certainly has immunologic potential, rejection is not seen in practice. However, when the attachment sites are transplanted using bone blocks, the bone can elicit an immunological response in the recipient. In practice this does not result in rejection of the graft.73,82 It is not exactly known whether the transplant must contain living cells or if it should only serve as a template which is repopulated by cells from the patient.
Radiation effects on Toxoplasma antigens: different immune responses of irradiated intact tachyzoites or soluble antigens in experimental mice models
Published in International Journal of Radiation Biology, 2020
Andrea da Costa, Nanci do Nascimento, Andrés Jimenez Galisteo, Aline Bastos Dias dos Passos, Heitor Franco de Andrade
In our model, the whole process was performed without the addition of adjuvants to the immunogen, obtaining a humoral, cellular and protective immune response in both the protein extracts and the irradiated intact tachyzoites. Modifications caused in proteins after ionizing gamma irradiation seems modify antigens making them more efficiently recognized by the immune response, generating both antibody and cytotoxic cell production and easily stored and preserved. This report clearly shows that gamma radiation mimics biological processes for immune cooperation, aside to nucleic acids effects, and certainly these effects are potent tools in vaccine development. Radiation is an important tool for vaccine design and production both by its genomic sterilization effects, but also for their gentle antigen immunogenicity enhancement.
Antibacterial application and toxicity of metal–organic frameworks
Published in Nanotoxicology, 2021
Wanling Zhao, Jinqiong Deng, Yan Ren, Liyuan Xie, Weirong Li, Qi Wang, Shengqing Li, Sijun Liu
Traditional metal antimicrobial agents and antimicrobial carriers are mainly divided into organic antimicrobial agents such as quaternary ammonium salts, natural antimicrobial agents such as chitosan, metal ions and their elemental substances, and inorganic antimicrobial agents represented by oxides such as TiO2and CeO2. However, these antimicrobials often have some disadvantages, such as poor heat resistance, difficulty in large-scale production, short service life, high metal toxicity and sterilization only in the presence of ultraviolet radiation and expensive raw materials. Compared with them, metal organic frameworks show long-lasting and efficient antibacterial performance, low costing, high loading rate, wide antibacterial spectrum, organic ligands, and inorganic metals cooperate to enhance antibacterial effect.
Nanostructured lipid carrier-based smart gel: a delivery platform for intra-articular therapeutics
Published in Autoimmunity, 2021
Chetan Shinde, Madhugiri Prakash Venkatesh, Tegginmat Pramod Kumar, Deeksha Ramananda Pai
Gamma irradiation of pharmaceuticals is simple, efficient, and convenient for terminal sterilization of pharmaceuticals and is recommended by European Pharmacopoeia [34,35]. The optimized formulation purged with nitrogen, sealed in borosilicate glass vials was gamma irradiated (Microtrol, Bangalore, India -Cobalt-60 source) for 15.76 kGy dose at 25 °C for sterilization [36]. Compendial sterility testing was carried out on irradiated samples to ascertain the effectiveness of sterilization.
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