Silver
Silver Uses, Dosage, Side Effects, Food Interaction and all others data.
Silver (Ag) is a chemical element that belongs in the family of transition metals in the periodic table. It has a high electrical conductivity, thermal conductivity, and reflectivity. Silver exists as a pure elemental form, alloy with other metals, and mineral. Having critical roles in various applications inducing chemical and industrial fields, silver compounds have also been used in the field of medicine for centuries due to their broad-spectrum biological actions. Silver nanoparticles especially have been widely used in industrial, household, and healthcare-related products due to their potent antimicrobial activity. Silver nitrate and Silver sulfadiazine have been used as topical antibacterial agents for the treatment of skin infections, while Silver sulfadiazine has also been valued for topical burn treatment . Silver and its compounds have been used in trials studying the management of dental caries since the 1800s, and they may be found in dental pastes as an active ingredients. However, some drawbacks of dental use of silver compounds include tooth discolouration and pulp irritation .
Silver exhibits a broad-spectrum antimicrobial activity. Silver ions were shown to mediate an effective antibacterial action against Streptococcus mutans, one of major bacteria present in the human oral cavity and one of etiological microorganism of dental caries . A study reported a dose-dependent antimicrobial activity of silver nanoparticles against MRSA and non-MRSA bacteria . Silver nanoparticles were also shown to mediate antibacterial activity against Gram-positive S. aureus and Gram-negative E. coli by inhibiting the growth .
In experimental dinitrochlorobenzene-induced inflammatory models in porcine or murine skin, topical application of silver nitrate and nanocrystalline silver were shown to exert anti-inflammatory effects associated with lymphocyte apoptosis, decreased expression of pro-inflammatory cytokines, and reduced gelatinase activity . In a rat model of ulcerative colitis, orally or intracolonically administered nanocrystalline silver were shown to suppress matrix metalloproteinase (MMP-9), tumour necrosis factor (TNF), and interleukin-β (IL-β) and IL-12 .
| Trade Name | Silver |
| Availability | Prescription only |
| Generic | Silver |
| Silver Other Names | Argentum metallicum, Colloidal silver, Nanosilver, Silver colloidal, Silver nanoparticles, Silver, colloidal |
| Related Drugs | Betadine, iodine topical, ethanol topical, salicylic acid topical, povidone iodine topical, Compound W, Wart Remover, Dakins Full Strength Solution, cantharidin topical |
| Type | |
| Formula | Ag |
| Weight | Average: 107.8682 Monoisotopic: 106.90509302 |
| Protein binding | Silver absorbed in the body as Ag+ bind rapidly to various proteins including albumin and macroglobulin as inert complexes for distribution to bone and soft tissues . |
| Groups | Approved, Investigational |
| Therapeutic Class | |
| Manufacturer | |
| Available Country | |
| Last Updated: | September 19, 2023 at 7:00 am |
Uses
Indicated for the treatment of acne for topical use or the management of dental caries for dental use.
Silver is also used to associated treatment for these conditions: Acne
How Silver works
The majority of released silver ions precipitate with chloride or phosphate anions or bind to albumins, macroglobulins, or tissue debris . While bound silver ions do not exert antibacterial actions, they may potentially play a role in silver toxicity in case of chronic exposure . Silver ions mediate antibacterial effects via disrupting the bacterial, fungal, and protozoal cell membranes; they bind to disulphide in membrane proteins, readily allowing penetration through the membranes and intracellular absorption via pinocytosis . They may also bind to negatively-charged peptidoglycans in the cell wall via electrostatic interactions, leading to disruption of membrane transport function and loss of structural integrity . Silver ions also bind to and oxidize sulphydryl groups (SH) in bacterial cytoplasmic enzymes to aberrate their function in metabolic processes. Silver nanoparticles may cause an increase in reactive oxygen species (ROS) inside the microbial cells leading to metal-induced oxidative stress and cell damage . They also modulate cellular signal system via inhibition of phosphorylation of essential bacterial proteins to eventually cause cell death . It is also reported that silver ions also attach to guanine in bacterial DNA, which inhibits DNA replication . While it is not fully understood, the mode of action of silver compounds in preventing and arresting dental caries is thought to involve inhibition of the demineralization process in addition to cytoplasmic and membrane function perturbation mentioned above . Silver compounds may directly interact with hydroxyapatite, a major tooth component .
Toxicity
Acute oral LD50, acute dermal LD50, and acute inhalation LD50 for 4 hours in rat are >5000 mg/kg, >2000 mg/kg, and >5.16 mg/m^3, respectively .
While individuals experiencing mild to moderate silver toxicity remain asymptomatic, chronic inhalation has been associated with mild chronic bronchitis and rare cases of exposure to large amounts of silver have been associated with symptoms of peripheral neuropathy, decreased mental status, and seizures . Argyria is a detoxification mechanism for excess silver where the body sequesters and deposits excess silver in the blood vessels and connective tissue to render it in the form of silver protein complexes or silver sulphide . The development of argyria through occupational exposure is reported to be a slow process . While argyria does not cause significant pathological damage in any tissue , heavy deposition of insoluble silver precipitates can cause discoloration or blue-grey darkening of the eyes, nasal septum, throat, skin, and other internal organs following repeated exposure . Signs from prolonged intake of low doses of silver compound may include fatty degeneration of the liver and kidneys, and changes in blood cells . Silver may cause metal fume fever, and colloidal silver preparations are known to exert harmful effects in humans .
Food Interaction
No interactions found.Silver Disease Interaction
Volume of Distribution
Following exposure to large amounts, excess silver is reported to accumulate in skin, liver, kidneys, spleen, corneas, gingival, mucous membranes and nails . In a study of rats with ligated bile ducts, deposition of silver was 48% in the liver and 2.5% in the gastrointestinal tract . Clinical and experimental studies suggest that silver is bound as inert precipitates in lysosomal vacuoles of the blood brain barrier and blood-CSF barrier without being absorbed into neurological tissue .
Elimination Route
Although metallic silver is inert in the presence of human tissues, silver and its compounds may dissociate upon contact with skin surface, body fluids, and secretions, allowing the silver ions to be absorbed into the blood circulation . Soluble silver salts are absorbed from the respiratory and gastrointestinal tracts. However, up to 90-99% of orally ingested silver is not absorbed and percutaneous absorption of silver ions through intact or damaged skin is also reported to be low . Absorbed silver ions are deposited into elastic and connective tissues throughout the body . Biologically active silver ions mainly binds to intracellular proteins as inert complexes, and readily binds and precipitates with inorganic cations like chloride and phosphate, which explains low absorption .
Half Life
The biological half-life for silver is a few days for animals and up to 50 days for human liver . In humans, the biological half-life of silver in lungs has been estimated to range from 1 to 52 days .
Elimination Route
Silver mainly undergoes biliary elimination to be excreted as feces . Findings from a rat study demonstrates that biliary excretion accounted for between 24% and 45% of total silver administered, and animal studies indicate that fecal elimination may account for up to 99% of the ingested silver .
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