Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Web – sheet or filament bases; compositions of bandages; or...
Patent
1997-08-06
2000-11-07
Levy, Neil S.
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Web, sheet or filament bases; compositions of bandages; or...
424404, 424405, 424406, 424409, 424421, 424445, 424617, 424618, 424630, 424642, 424722, 424 7806, 514494, 514495, 514500, A61N 970
Patent
active
061433187
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to an antimicrobial material for combatting infections.
To combat infections at wound sites a variety of antibacterial agents have been incorporated into wound dressings. Some of these agents have been shown to have a deleterious effect on the delicate environment of a healing wound and may indeed retard the rate of wound healing. Individually, silver and copper are known to have useful biocidal properties (see Pyle et al, J. Appl. Bacteriology 1992. vol. 72, no.1, pp 71-79).
The use of glasses which can dissolve in water and body fluid and which are applied internally of the body are well-known. These glasses are formed from phosphorus pentoxide and may be modified to dissolve over a period of minutes, months or even years, as required. To date, such glasses have been used, in medicine, for the controlled release of a number of agents, for example, drugs, hormones and trace elements, but in each case the glass has been applied internally of the body to allow the agent to leach out into the body's circulatory system.
It is known that certain glasses, in which the usual glass former, silicon dioxide, of traditional glasses is replaced with phosphorus pentoxide as the glass former, are soluble in water and body fluids. The rate of dissolution is controlled largely by the addition of glass modifiers such as calcium oxide. In simple terms, the greater the concentration of the modifier the slower is the rate of dissolution. The rates of dissolution which can be imparted to the glasses may range from minutes to months or even to several years. Soluble phosphate based glasses which have demonstrated good biocompatibility can incorporate inorganic metals such that a sustained release of the metals can be provided at the wound site.
Controlled release glasses (CRGs) which release silver ions to combat infections as described in WO-A-90/08470 of Giltech Limited, for example.
It has now been found that a combination of metal ions can, if suitably presented, reduce the amount of anti-microbial metal ions required to achieve bacteriostatic or bactericidal activity, whilst at the same time lowering the inflammatory response of the tissue.
The present invention therefore provides a method of combatting infection in a wound (such as microbial or fungal infection, for example bacterial, viral, or fungal infection) whilst maintaining cell viability, said method comprising providing a controlled release glass containing a combination of two or more agents selected from the group consisting of metals, selenium and boron. The agents are selected and combined together in concentrations sufficient to achieve bacteriostatic or bactericidal benefit. The concentrations of each agent is low enough to avoid cell death in the healing wound (for example due to protein binding etc) but in combination is sufficient to achieve at least bacteriostasis. By careful selection of the combination of agents used infection can be combatted and wound healing promoted. In one embodiment the agents are selected from the group consisting of copper, silver, magnesium, zinc, cerium, manganese, bismuth, selenium and boron. Preferably at least one agent is silver, boron, bismuth, manganese, copper, cerium or zinc.
The present invention also provides a controlled release glass (CRG) composition for combatting infection in cells (such as microbial or fungal infection, for example bacterial or viral infection, including parasitic infections, for example bilharzia and blue/green algae) whilst maintaining cell viability. The glass controllably releases quantities of at least two agents selected from the group consisting of metals, selenium and boron; the combined concentration of released agents being sufficient to combat infections whilst aiding wound healing.
The controlled release glass according to the present invention comprises the agents set out above and in one embodiment the agents are selected from the group consisting of copper, silver, magnesium, zinc, cerium, manganese, bismuth, selenium and boron. Glasses containing
REFERENCES:
patent: 5180585 (1993-01-01), Jacobson et al.
patent: 5470585 (1995-11-01), Gilchrist
Derwent English Abstract of Japanese Patent Application 01/317133.
Derwent English Abstract of Japanese Patent Application 02/258256.
Derwent English Abstract of Japanese Patent Application 05/001226.
Derwent English Abstract of Japanese Patent Application 03/146436.
Patent Abstract of Japan; Publication No. JP6080527; Publication Date Mar. 22, 1994; Appli. No. JP920257364; Appli. Date Aug. 31, 1992 by Katsuhiro et al. for Antimicrobial Agent.
Soderberg et al., The Effects of an Occlusive Zinc Medicated Dressing on the Bacterial Flora in Excised Wounds in the Rat, from Infection, vol. 17, 1989.
Schmidt-Lorenz, from Hygiene & Medizin, Sep. 1981, pp. 389-398, with English language Summary.
Sheridan et al., The Effect of Antibacterial Agents on the Behaviour of Cultured Mammalian Fibroblasts, from Journal of Materials Science, vol. 6, 1995, pp. 853-856.
Gilchrist Thomas
Healy David Michael
Giltech Limited
Levy Neil S.
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