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Composite alginate-hyaluronan sponges for the delivery of tranexamic acid in post-extractive alveolar wounds
Full text linkThe management of wounds in patients on anticoagulant therapy who require oral surgical procedures is problematic and often results in a non-satisfactory healing process. Here we report a method to prepare an advanced dressing able to avoid uncontrolled bleeding by occluding the post-extractive alveolar wounds, and simultaneously, capable of a fast release of tranexamic acid (TA). Composite alginate/hyaluronan (ALG/HA) sponge dressings loaded with TA were prepared by a straightforward internal gelation method followed by a freeze-drying step. Both blank and drug-loaded sponges were soft, flexible, elegant in appearance and non-brittle in nature. SEM analysis confirmed the porous nature of these dressings. The integration of HA influenced the microstructure, reducing the porosity, modifying the water uptake kinetic and increasing the resistance to compression. TA release from ALG/HA sponges showed a controlled release up to 3h and it was faster in the presence of HA. Finally, an in vitro clotting test performed on human whole blood confirmed that the TA-loaded sponges significantly reduce the blood clotting index (BCI) by 30% compared to ALG/HA20 sponges. These results suggest that, if placed in a socket cavity, these dressings could give a relevant help to the blood hemostasis after dental extractions, especially in patients with coagulation disorders
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Hydrogel dressings
No full textHydrogels are materials with unique properties that allow them to be applied in major aspects of human activities. Modern hydrogel wound dressings are often classified as hydrocolloid dressings, alginate dressings, flat hydrogel dressings, amorphous hydrogel dressings, foam dressings, films, and composite materials composed of a fibrous substrate impregnated with hydrogel forming polymer. This chapter considers several methods used for the production of hydrogel wound dressings by polymerization of monomers and cross‐linking of polymers. Cross‐linking of polymers is a more common way of producing hydrogel wound dressings because it gives an opportunity to avoid contamination of the final product with unreacted toxic or irritating components (monomers and initiator). There are a few cross‐linking techniques that can be used for the production of hydrogel dressings: physical cross‐linking; cross‐linking by low molecular weight compounds; ultraviolet, gamma, and electron beam irradiation; condensation reactions between functional groups of polymers; enzymatic cross‐linking; and interpenetrating polymer network cross‐linking
Preparation and optimization of PMAA-Chitosan-PEG nanoparticles for oral drug delivery
No full textINTRODUCTION: In the current study pH sensitive polymethacrylic acid – chitosan–polyethyleneglycol (PCP) nanoparticles, were developed through a free radical polymerisation process [1]. Metoprolol was used as a model active substance and the obtained PCP nanoparticles presented excellent drug loading (20–30%) and bioadhesion properties
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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