Silver compounds properties

Upper respiratory tract irritation bas been observed in bumans at estimated exposure levels of between 0.04 and 0.4 mg silver/m for less than 1 to greater than 10 years. Irritant effects are considered to be related to tbe caustic properties of tbe various silver compounds, ratber than tbe silver itself. 

In 2008, an antimicrobial ASA plastic type was introduced (39). This was the first ASA type with antimicrobial properties. The antimicrobial material contains silver compounds that are incorporated into the plastic in order to impart its surface with a germicidal effect. 

Silver that is released into the environment may be carried long distances in air and water. Rain washes silver compounds out of many soils so that it eventually moves into the groundwater. Silver is stable and remains in the environment in one form or another until it is taken out again by people. Because silver is an element, it does not break down, but it can change its form by combining with other substances. Over time it may change from the form first released, to metallic silver, and then back to the same or other compounds. The form it is found in depends on environmental conditions. More information on the chemical and physical properties of silver compounds can be found in Chapter 3, on its production, use, and disposal in Chapter 4, and on silver in the environment in Chapters 4 and 5. 

Upper respiratory irritation has been observed in humans at estimated exposure levels of between 0.039 and 0.378 mg silver/m for less than 1 to greater than 10 years. Evidence that silver colloid can act as an irritant is provided by the fact that ultrastructural damage was seen in the tracheal epithelium of rabbits following inhalation exposure to an unknown concentration of silver colloid. However, these effects are likely to be related to the caustic properties of the compounds, not to the presence of silver. The effects are not expected to persist when exposure to air containing silver compounds has stopped. 

Important physical and chemical properties of silver and selected silver compounds are given in Tables 3-7 through 3-12. 

PROPERTIES AND USES OF SILVER COMPOUNDS Silver and silver salts Silver sulphadiazine... 

Studies of the antimicrobial and therapeutic properties of silver and its derivatives have yielded an extensive scientific literature, ranging from clinically- to biochemically-based papers. The latter area includes studies in enzymatic and other macromolecular interactions to silver resistance encompassing plasmid-mediated patterns. The reduction to one silver compound (AgSD) in the current British National Formulary and to two compounds (AgSD and silver nitrate ophthalmic solution) in USP XXII may not be a true reflection of the use of silver in health care today. Silver compounds also find use in non-clinical situations, for example, as water disinfectants and, not considered in this review, as silver staining techniques for microscopy. 

Antimicrobial properties of silver have been known and utilized for centuries. It is well established that only silver ions are antimicro-bially active, while elemental silver is not. Many biomedical devices have been coated with silver and/or silver compounds for antimicrobial purposes. The applications of surfaces treated with silver or its compounds include devices such as topical wound dressings, urinary catheters, endotracheal tubes, cardiac valves, etc.72 Electroless deposition of silver or its compounds can quite successfully be used for coating of biomedical devices. 

Modifying the surfaces of plastics to impart specialized properties is also likely to he a growing area. Acrylonitrile butadiene styrene (ABS) has recently been surfece treated with silver compounds to impart anti-bacterial properties which remain... 

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