Silver Pharmacology: Past, Present and Questions for the Future

Silver pharmacology is at the cross-roads. It has a long history as a chemosterilent but is currently denigrated by some vested interests and other 'knowledge monopolies'. It deserves better--particularly in these critical times of ever mounting incidence of antibiotic resistance. This reappraisal outlines some approaches to a dispassionate debate as to why we should, or should not, be reconsidering silver as an addition to (not a substitute for) other antibiotics at the front line of medicine. This will require more understanding about (i) the chemistry of silver in a biological environment; (ii) the different physical and bio-reactive properties of ionised silver (Ag(I)) and nanoparticulate metallic silver (Ag(o)); (iii) the antibiotic potential of both Ag(I) and Ag(o); and (iv) establishing objective Quality Controls for potential silver therapies. Six appendices (A-F) provide some technical data and focus further upon the need to clearly define (a) procedures for manufacturing nanoparticulate metallic silver (NMS); and (b) the purity and properties of NMS preparations--especially stability, antibiotic efficacy and safety of products offered for clinical evaluation. A further appendix (G) deals with some political considerations currently impeding impartial clinical research on silver therapeutics.