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    The mechanisms of silver release and the sustained release of silver

    Silver ions can be obtained from various donor systems such as salts, chelated structures, ion exchange systems or even metallic silver. Although they all present the same antimicrobial silver ion,Ag+, each of these donor mechanisms for silver ions have a unique activation mechanism and release profile21 . The donor system may impact the amount of silver ions released and for the rate of release, which in turn is significant for the antimicrobial effect. It is therefore important to select the right donor system and optimise the conditions for the system to obtain an optimal release profile for antimicrobial efficacy within the infected wound. An in vitro experiment has illustrated the need for a sustained silver release exposing bacteria to aconstant suppression during wear time to avoid regrowth25. A bacterial biofilm assay simulating wound bed conditions was used. A small volume of protein solution was added every day to imitate inactivation of silver by slough. Products with sustained silver release (high or low silver concentration) or no sustained release (high concentration) were compared. Products with high concentrations had the best eradication effect at day 1. However, if there was not a sustained release of silver, the bacteria re-colonised the wound bed at day 7, while products with sustained silver release (high and low) continued decreasing the bacterial load at day 7. This illustrates the need for a constant suppression of bacteria, by sustained release of silver, throughout the dressing wear time to avoid regrowth. The sustained silver release system of Biatain® Silicone Ag and Biatain Ag is based on an ion exchange system, where silver is bound to a zirconium phosphate crystal by ionic interaction with the ortho-phosphate groups in the zirconium phosphate molecule (Figure 1). The zirconium phosphate forms a sheet-like crystal with an average size of 1.3 μm wherein the silver binds in the grid structure at a loading concentration of approximately 10%.

    Mechanism of silver ion release from the Biatain Silicone Ag and Biatain Ag.

    Figure 1

    Figure 5: Mechanism of silver ion release from the Biatain Silicone Ag and Biatain Ag. The zirconium crystals are homogeneously incorporated into the foam during the foam manufacturing process as inert particles. The silver ion binds to the ortho-phosphate by ionic interactions and is only released when exchanged with other cations. Since the wound exudate has a high concentration of cations( K+, Na+, Ca2+, Mg2+), the exudate triggers the release of silver from Biatain® Silicone Ag and Biatain Ag. When Biatain Silicone Ag or Biatain Ag is placed on an exuding wound, the sustained silver release is carried out in response to the level of exudate (Figure 1).

    Sustained release of silver

    The release rate of silver ions varies between existing dressings on the market. Some dressings release the silver ions rapidly in either small or large amounts. Others, like Biatain® Silicone Ag and Biatain Ag, have a sustained release of silver ions over several days. In vitro release profiles from different silver dressings are shown in Figure 3. As described in the previous section, sustained release of silver ions ensures a constant, unfavourable environment for bacteria25.

    The sustained silver release profile of Biatain Silicone Ag and Biatain Ag is controlled by several factors, including the volume of exudate absorbed by the dressing, the rate of cation diffusion into the zirconium crystals, the silver exchange rate and the rate of silver diffusing out into the wound bed. Biatain Silicone Ag and Biatain Ag have sustained release of silver up to 7 days (Figure 2) 26.

    The release of silver from a wound dressing can be investigated in a Franz cell setup where the wound dressing is mounted in a cup exposing a specified area of the wound contact side of the dressing to a continuous flow of imitated wound fluid. The silver ions will then be released into the fluid and the release rate can be determined by measuring the silver ion concentration in the fluid by atomic absorption spectroscopy. In a study published in 201526

     

    Biatain Silicone Ag and Biatain Agand other well-known silver dressings on the market were tested. Figure 3A shows release curves over 7 days. Biatain Silicone Ag and Biatain Ag showed a significantly greater, sustained release of silver over the 7-day period than any of the other dressings tested26.

     

    Figure 3B illustrates how Biatain Silicone Ag and Biatain Ag with their sustained silver release profiles had the highest accumulated silver release over 7 days26.

    Silver release profiles for Biatain Silicone Ag, Biatain Ag and other silver dressings.

    Figure 2

    .

    A: Release of silver, measured in 4-hour intervals for 7 days
    B: Accumulated release of silver over 7 days showing the total amount release from the dressing over time26. The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) has previously been reported tobe 12.5μg/ml for Staphylococcus aureus and 7.5μg/ml for Pseudomonas aeruginosa 32

    The sustained release of silver by Biatain Silicone Ag and Biatain Ag is reflected in the results from a published in vitro study demonstrating antimicrobial efficacy against a wide range of pathogenic micro organisms commonly found in non-healing and infected wounds. The antimicrobial effect wascontinuous for the full 7-day test period.20

    Reference list

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    1. International Wound Infection Institute (IWII). Wound infection in clinical practice. Wounds International. 2016.

    2. Coloplast A/S, ReD associates. Data on file. 2014.

    3. Schultz G, Bjarnsholt T, James GA, Leaper DJ, McBain AJ, Malone M, et al. Consensus guidelines for the identification and treatment ofbiofilms in chronic nonhealing wounds. Wound Repair and Regeneration. 2017;25(5):744-57.

    4. World Union of Wound Healing Societies (WUWHS). Florence Congress, Position Document. Management of biofilm. 2016.

    5. Appropriate use of silver dressings in wounds. An expert working group consensus. International consensus. London; 2012.

    6. Lansdown AB. A review of the use of silver in wound care: facts and fallacies. British Journal of Nursing. 2004;13(6):s6-19.

    7. Rodriguez-Arguello J, Lienhard K, Patel P, Geransar R, Somayaji R, Parsons L, et al. A Scoping Review of the Use of Silver-impregnatedDressings for the Treatment of Chronic Wounds. Ostomy Wound Management. 2018;64(3):14-31.

    8. Dissemond J, Bottrich JG, Braunwarth H, Hilt J, Wilken P, Munter KC. Evidence for silver in wound care - meta-analysis of clinical studiesfrom 2000-2015. Journal of the German Society of Dermatology. 2017;15(5):524-35.

    9. Norman G, Westby MJ, Rithalia AD, Stubbs N, Soares MO, Dumville JC. Dressings and topical agents for treating venous leg ulcers.Cochrane Database of Systematic Reviews. 2018(6):1-289.

    10. Münter KC, Beele H, Russell L, Crespi A, Grochenig E, Basse P, et al. Effect of a sustained silver-releasing dressing on ulcers with delayedhealing: the CONTOP study. Journal of wound care. 2006;15(5):199-206.

    11. Jørgensen B, Price P, Andersen KE, Gottrup F, Bech-Thomsen N, Scanlon E, et al. The silver-releasing foam dressing, Contreet Foam,promotes faster healing of critically colonised venous leg ulcers: a randomised, controlled trial. International wound journal. 2005;2(1):64-73.

    12. Rayman G, Rayman A, Baker NR, Jurgeviciene N, Dargis V, Sulcaite R, et al. Sustained silver-releasing dressing in the treatment of diabeticfoot ulcers British Journal of Nursing. 2004;14(2);109-14.

    13. Humbert P, Zuccarelli F, Debure C, Vendeaud Busquet F, Bressieux J-M, Bedane C, et al. Leg Ulcers Presenting Local Signs of Infection:Interest of Biatain Argent Wound Dressing. Journal des Plaies et Cicatrisations. 2006;52(9):41-7.

    14. Lázaro-Martínez JL, Álvaro-Afonso FJ, García-Álvarez Y, García-Morales E, Sanz-Corbalán I, Molines-Barroso RJ. Clinical and microbiologicaleffectiveness of a hydropolymer alveolar dressing with ionic silver complex and silicone adhesive. Poster, EWMA(EPP021); 2018.

    15. Leaper D, Münter C, Meaume S, Scalise A, Mompó NB, Jakobsen BP, et al. The Use of Biatain Ag in Hard-to-Heal Venous Leg Ulcers:Meta-Analysis of Randomised Controlled Trials. PLoS ONE. 2013;8(7):e67083.

    16. Jemec GB, Kerihuel JC, Ousey K, Lauemoller SL, Leaper DJ. Cost-Effective Use of Silver Dressings for the Treatment of Hard-to-HealChronic Venous Leg Ulcers. Plos One. 2014;9(6):e100582.

    17. Mouës C, Heule F, Legerstee R, Hovius S. Five Millennia of Wound Care Products - What is New? A Literature Review. Ostomy WoundManagement. 2009;55(3):16-8.

    18. Sibbald R, Williamson D, Orsted H, Campbell K, Keast D, Krasner D, et al. Preparing the Wound Bed - Debridement, Bacterial Balance, andMoisture Balance. Ostomy Wound Management. 2000;46(11):14-35.

    19. Adderley UJ. Managing wound exudate and promoting healing. British Journal of Community Nursing. 2010;15(3):15-20.

    20. Christiansen C, Huniche GB, Allesen-Holm M. In vitro evaluation of a silver foam dressing with and without silicone adhesive againstbiofilms and a broad range of microorganisms. Poster, EWMA(EPP025); 2018.

    21. Lansdown AB. Silver in health care: antimicrobial effects and safety in use. Current Problems in Dermatology. 2006;33:17-34.

    22. Percival SL, Thomas J, Linton S, Okel T, Corum L, Slone W. The antimicrobial efficacy of silver on antibiotic-resistant bacteria isolated fromburn wounds. International wound journal. 2012;9(5):488-93.

    23. Böttrich JG, Brill FHH, Dissemond J, Steinmann J, Münter KC, Schümmelfeder F, et al. A Systematic Review of the Risk of BacterialResistance to Silver. Poster, EWMA; 2018.

    24. Percival SL, Woods E, Nutekpor M, Bowler P, Radford A, Cochrane C. Prevalence of Silver Resistance in Bacteria Isolated from DiabeticFoot Ulcers and Efficacy of Silver-Containing Wound Dressings. Ostomy Wound Management. 2008;54(3):30-40.

    25. Kostenko V, Lyczak J, Turner K, Martinuzzi RJ. Impact of Silver-Containing Wound Dressings on Bacterial Biofilm Viability and Susceptibilityto Antibiotics during Prolonged Treatment. Antimicrobial Agents and Chemotherapy. 2010;54(12):5120-31.

    26. Burger C, Lemoult S, Andersen MB. Silver release profile and antibacterial effect of a new silver foam dressing with silicone adhesive.Poster, EWMA(EPP025); 2018.

    27. Malone M, Bjarnsholt T, McBain AJ, James GA, Stoodley P, Leaper D, et al. The prevalence of biofilms in chronic wounds: a systematicreview and meta-analysis of published data. Journal of wound care. 2017;26(1):20-5.

    28. Bjarnsholt T. The Role of Bacterial Biofilms in Chronic Infections. Acta pathologica, microbiologica, et immunologica Scandinavica.2013;121(s136):1-58.

    29. Costerton JW. Bacterial Biofilms: A Common Cause of Persistent Infections. Science. 1999;284(5418):1318-22.

    30. Crone S, Garde C, Bjarnsholt T, Alhede M. A novel in vitro wound biofilm model used to evaluate low-frequency ultrasonic-assisted wounddebridement. Journal of wound care. 2015;24(2):64-72.

    31. Bessa LJ, Fazii P, Di Giulio M, Cellini L. Bacterial isolates from infected wounds and their antibiotic susceptibility pattern: some remarksabout wound infection. International wound journal. 2013;12(1):47-52.

    32. Yin HQ, Langford R, Burrell RE. Comparative Evaluation of the Antimicrobial Activity of ACTICOAT Antimicrobial Barrier Dressing. Journalof Burn Care & Rehabilitation. 1999;20(3):195-200.

    33. ASTM E2149-13a, Standard Test Method for Determining the Antimicrobial Activity of Antimicrobial Agents Under Dynamic ContactConditions. ASTM International. 2013.

    34. prEN16756 (draft). Antimicrobial wound dressings – Requirements and test methods. 2014.

    35. Howell-Jones RS, Wilson MJ, Hill KE, Howard AJ, Price PE, Thomas DW. A review of the microbiology, antibiotic usage and resistance inchronic skin wounds. Journal of Antimicrobial Chemotherapy. 2005;55(2):143-9.

    36. Bowler PG, Duerden BI, Armstrong DG. Wound Microbiology and Associated Approaches to Wound Management. Clinical MicrobiologyReviews. 2001;14(2):244-69.

    37. Daeschlein G. Antimicrobial and antiseptic strategies in wound management. International wound journal. 2013;10 Suppl 1:9-14.

    38. Thomas S. Laboratory findings on the exudate-handling capabilities of cavity foam and foam-film dressings. Journal of wound care.2010;19(5):192-9.

    39. White R, Cutting KF. Modern exudate management: a review of wound treatments. Poster, EWMA(EPP025); 2018.

    40. Romanelli M, Vowden K, Weir D. Exudate management made easy. Wounds International. 2010;1(2):1-6.

    41. Andersen MB. Comparison of 24 hours fluid handling and absorption under pressure between four wound dressings with Ag and siliconeadhesive. EWMA(EP296); 2016.

    42. Baños AM, Nogueras FI, Palomar LF. Clinical evaluation of a silver dressing in the treatment of infected and colonized ulcers. Revista deenfermería. 2008;31(3):42-8.

    43. Senet P, Bause R, Jorgensen B, Fogh K. Clinical efficacy of a silver-releasing foam dressing in venous leg ulcer healing: a randomisedcontrolled trial. International wound journal. 2014;11(6):649-55.

    44. Flanagan M. Wound measurement: can it help us to monitor progression to healing? Journal of wound care. 2003;12(5):189-94.

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