In-vitro Evaluation of a Novel Silver-containing Super Absorbent Dressing

Introduction: Silver is known to have excellent antimicrobial activity, which is useful in the practice of wound care and the prevention of infections. However, above certain thresholds, silver toxicity can occur, particularly to the keratinocytes and fibroblasts, which can affect wound healing. This study looked to evaluate the safety of a novel silver-con- taining super absorbent dressing (SAP) intended for use in heavy exudate wounds. Methods: Triplicate samples of the silver SAP and a silver non-super absorbent dressing, which acted as a control, were cut into 25cm2 pieces and were soaked with a simulated body fluid (SBF) for two minutes and then allowed to drip dry. The silver SAP was then placed in a leaching basket and every 24 hours for a 7-day period, 50mL of the SBF was poured onto the dressings. The dressings were then placed into a release solution and then the solution was examined by atomic absorption spectropho- tometer to determine the rate of silver ion release. Results: The maximum daily amount of silver that was released by the novel silver SAP during the 7-day study period was 117 micrograms. This was comparable to the control silver non-SAP dressing, which released 115 micrograms, and both of these readings occurred on day one. The cumula- tive dose of silver for the silver SAP was 765 mcg, which again was compara- ble to the control silver non-SAP, whose cumulative dose was 741 mcg. Discussion: The silver-containing super absorbent dressing did not sig- nificantly increase risk for silver toxicity in non-intact skin, with the daily maximum level that was released was well below the World Health Orga- nization silver toxicity reference dose of 6.5mcg/kg. This study suggests that the silver super absorbent dressing could be a preferable alternative to silver non-super absorbent wound dressings for the prevention of infection in wounds with exudate.