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The application of porous materials is increasingly being used in orthopaedic surgery due to its good results. Bone growth within the pores results in excellent mechanical fixation with the bone, as well as good bone regeneration. The pores, in addition to being colonised by bone, produce a decrease in the modulus of elasticity that favours the transfer of loads to the bone. This research shows the results of an experimental study where we have created critical osteoperiosteal defects of 10 mm on rabbit’s radius diaphysis. In one group of 10 rabbits (experimental group) we have implanted a bioactive porous titanium cylinder, and in another group we have allowed spontaneous regeneration (control group). Mechanical tests were performed to assess the material. Image diagnostic techniques (X-ray, scanner and 3D scan: there are no references on the literature with the use of CT-scan in bone defects) and histological and histomorphometric studies post-op and after 3, 6 and 12 months after the surgery were performed. All the control cases went through a pseudoarthrosis. In 9 of the 10 cases of the experimental group complete regeneration was observed, with a normal cortical-marrow structure established at 6 months, similar to normal bone. Titanium trabecular reached a bone percentage of bone inside the implant of 49.3% on its surface 3 months post-op, 75.6% at 6 months and 81.3% at 12 months. This porous titanium biomaterial has appropriate characteristics to allow bone ingrowth, and it can be proposed as a bone graft substitute to regenerate bone defects, as a scaffold, or as a coating to achieve implant osteointegration. info:eu-repo/semantics/publishedVersion

Introduction: Cannabidiol (CBD), the main non-psychotropic cannabinoid, has emerged as a potential therapeutic agent for the treatment of several disorders including cancer, neurodegenerative disorders and pain among others. However, its low aqueous solubility hinders the development of effective parenteral formulations [1]. The use of polymeric microparticles as CBD carriers could resolve this challenge and allows to obtain an extended CBD release after a single administration [2]. Among all the available polymers, poly(lactic-co-glycolic acid) (PLGA), FDA approved for various medical applications, is one the most used. Ionizing radiation has been proposed as an effective sterilizing method for PLGA microparticles, which is essential for their parenteral administration [3]. The aim of this work was to evaluate the effect of gamma sterilization on the characteristics of CBD loaded microparticles. Methods: Microparticles with a CBD:PLGA ratio of 10:100 (10-Mps) and 20: 100 (20-Mps) were prepared by solvent evaporation technique, using PLGA-RG-502 as polymer, and sterilized by gamma irradiation at a dose of 25 kGy. All formulations were then characterized by DLS, SEM and DSC. CBD content and CBD release were also evaluated by HPLC. Results: No differences in particle morphology and particle size were detected between sterile and non-sterile formulations. All microparticles exhibited a spherical shape, a smooth surface, and an average particle size around 25 µm. DSC analysis showed the absence of the CBD melting peak in sterile and non-sterile CBD microparticles, indicating that it is dissolved or molecularly dispersed within the polymeric matrix and that no crystallization processes occurred during sterilization. However, a reduction on PLGA glass transition was appreciated in both 10-Mps and 20-Mps sterile formulations compared with their non-sterile counterparts. A significant lower CBD content was also detected in sterile microparticles, observing a CBD degradation during sterilization of 13.75% and 10.28% in 10-Mps and 20-Mps respectively. Finally, a faster CBD release was appreciated in sterile microparticles compared with their counterparts, due to the faster PLGA degradation in sterilized microparticles. Conclusions: Due to the CBD degradation during sterilization process and the acceleration of the release of this drug from PLGA microparticles, gamma irradiation is not an adequate method to sterilize CBD-PLGA-microparticles. References: [1]. Fraguas et.al. Drugs. 2018; 78(16):1665-1703. [2]. Fraguas et.al. Int J Pharm.202; 574:118916 [3]. De Oliveira et.al. Mater Sci Eng C Mater Biol Appl. 2017; 80:438-448.

Breast cancer is the most frequent neoplasm in the female population [...]

The potential of a new poly(magnesium acrylate) hydrogel (PAMgA) as a pharmaceutical excipient for the elaboration of matrix tablets for the extended release of highly hydrophilic drugs was evaluated. The polymer was synthetized with two different crosslinking degrees that were characterized by FTIR and DSC. Their acute oral toxicity was determined in a mouse model, showing no toxicity at doses up to 10 g/kg. Matrix tablets were prepared using metformin hydrochloride as a model drug and the mechanisms involved in drug release (swelling and/or erosion) were investigated using biorrelevant media. This new hydrogel effectively controlled the release of small and highly hydrophilic molecules as metformin, when formulated in matrix tablets for oral administration. The rate of metformin release from PAMgA matrices was mainly controlled by its diffusion through the gel layer (Fickian diffusion). The swelling capacity and the erosion of the matrix tablets influenced the metformin release rate, that was slower at pH 6.8, where polymer swelling is more intensive, than in gastric medium, where matrix erosion is slightly more rapid. The crosslinking degree of the polymer significantly influenced its swelling capacity in acid pH, where swelling is moderate, but not in intestinal fluid, where swelling is more intense.

Although ceramic-on-ceramic (CoC) bearings have been shown to produce the smallest amount of wear volume in vitro as well as in vivo studies when used for total hip arthroplasties (THA), concerns about the failure of these bearing surfaces persist due to early failures observed after short postoperative time. In this study, an exhaustive analysis of the early failure occurred on the new generation of ceramic bearings, consisting of a composite alumina matrix-based material reinforced with yttria-stabilized tetragonal zirconia (Y-TZP) particles, chromium dioxide, and strontium crystals, was performed. For this study, 118 CoC bearings from 117 patients were revised. This article describes a group of mechanical failure CoC-bearing BIOLOX THA hip prosthesis patients without trauma history. The retrieved samples were observed under scanning electron microscopy (SEM), composition was analyzed with energy dispersive X-ray spectroscopy (EDX), and damaged surfaces were analyzed by grazing-incidence X-ray diffraction (GI-XRD) and white light interferometry. In the short term, CoC articulations provided similar mechanical behavior and functional outcome to those in XLPE cases. However, 5% more early mechanical failures cases were observed for the ceramic components. Although the fracture rate of third generation CoC couples is low, the present study shows the need to further improve the third generation of CoC-bearing couples for THA. Despite the improved wear compared to other materials, stress concentrators are sources of initial crack propagation, such as those found in the bore-trunnion areas. Moreover, in view of the evidence observed in this study, the chipping observed was due to the presence of monoclinic phase of the Y-TZP instead of tetragonal, which presents better mechanical properties. The results showed that total safety after receiving a THA is still a goal to be pursued. info:eu-repo/semantics/publishedVersion

This work evaluates the effects of using non-conforming fly ash (Nc-FA) generated in a thermoelectric power plant as filler material for mortars made with natural sand (NA) and recycled sand from masonry waste (FRMA). The incorporation of powdered recycled masonry filler (R-MF) is also tested as an alternative to siliceous filler (Si-F). Three families of mortars were designed to study: the effect of replacing Si-F with Nc-FA on mortars made with NA; the effect of replacing Si-F with Nc-FA on mortars made with 50% of NA and 50% of FRMA; and the effect of replacing Si-F with R-MF on mortars made with NA and FRMA. Replacing Si-F with Nc-FA is a viable alternative that increases the mechanical strength, the workability and durability properties and decreases the shrinkage. The use of FRMA and Nc-FA improved the mechanical strength of mortars, and it slightly increased the shrinkage. The replacement of Si-F with R-MF on mortars made with FRMA is not a good alternative, because it has a negative impact on all of the properties tested. This work can help both to reduce cement and natural resources’ consumption and to increase the recycling rate of Nc-FA and FRMA