Download Disinfectants and antiseptics

13/11/2012
Gabor Pozsgai MD.
Faculty of Medicine University of Pécs
2012
• Inhibition of pathogen cell division
• Elimination of pathogens
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13/11/2012
• Antimicrobial drugs
– chemoterapeutics
– may be given systemically
• Disinfectants and antiseptics
– cannot be used systemically
• Urinary antiseptics are given systemically, but
exert their action locally in the urinary tract
• Antiseptics
– applied topically to mucous membranes or skin
• Disinfectants
– toxic, only for non sterilizable instruments and
objects
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• Phenol coefficient
– effect of compounds is compared to that of 5%
phenol
• The more concentrated the solution the less
time is needed for it to exert its effect
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Bacteriostatic/bactericidal
Sporocidal
Virucidal
Fungicidal
Parasiticidal
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Alcohols and glycols
Aldehydes
Phenols and derivatives
Acid derivatives
Halogens and halogen containing compounds
Oxidizing agents
Metals
Surface active detergents
Other compounds
• Aliphatic alcohols
– ethanol, isopropanol
– antimicrobial activity increases with number of
carbon atoms
– 70% solution is the most active
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• Aliphatic alcohols
– do not kill parasites and bacterial spores
– solutions have to be filtered through 0.22 μm
pores
– hydrogen peroxyde shlould be added
– may be used to the skin
– aerosol can be used to clean ventilators
– mostly in combinations
• Glycols
– triethylene glycol
– fumes are used to sterilize air
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• Widest spectrum
– bactericidal, sporocidal, virucidal, fungicidal
• React with amino moieties of proteins
– proteins are precipitated
– damage tissues
– mostly applied to objects
• Formaldehyde
– gaseous
– formalin
• saturated solution containing 34-38%
– 10% solution may be used to mucous membranes
– explosive when mixed with sodium hypochlorite
– often combined with anionic detergents
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• Formaldehyde
– the gas is used to sterilize rooms
– solid polymer is used
– releases formaldehyde if treated with steam
– may be explosive if too concentrated
• Methenamine
– urinary antiseptic
– releases formaldehyde in acidic urine
– often combined with mandelic acid
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• Glutaraldehyde
– used to sterilize instruments
– 24.5% glutaraldehyde in 70% isopropanol at
pH7.5-8.5
– very toxic to tissues
• have to be cleaned from instruments
• sodium bisulfite or sterile water
– can be combined with anionic detergents
• Phenol
– now obsolete
– at least 1-2% solution is needed
– 5% is toxic and precipitates proteins
– gets into the CNS and damages plasma
membranes
– excitatory symptoms, hypothermia, fainting
– only used for objects and discharges
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• Cresol
– poorly soluble in water
– mixed with anionic detergents
– bactericidal, parasiticidal
– more active at high temperatures
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Amylmetacresol
Chlorcresol
Thymol
Hexylresorcinol
– urinary antiseptic
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• Hexachlorophene
– bacteriostatic and fungistatic
– surgical hand antiseptic
– were used for newborns
– may be absorbed and damages the CNS
– carbanilide and salicylanilide derivatives are used
instead
– these cause rashes and photosensitivity
• Chlorhexidine
– not effective against Pseudomonas and Serratia
– used to the skin throat and wounds
– 4% chlorhexidine gluconate
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• Boric acid
– 5% solution or powder
– binds to pyridoxine
– sodium tetraborate in glycerol is used for oral
thrush of infants
– boric acid in vaseline
– may be used for vaginal irrigation
– very toxic in children if absorbed
• Benzoic acid
– preservative in food and drugs
– esters of paraoxybenzoic acid are more suitable
– methyl, ethyl, propyl or benzyl esters
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• Salicylic acid
– used in dermatology
– fungicidal and keratolytic
– relieves itch and sweating
– dissolved in alcohol, as dermal patch, ointment
and paste
• Mandelic acid
– urinary antiseptic
– decreases pH of urine to 5.0
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• Iodine
– bactericidal, sporocidal, virucidal, fungicidal
– low tissue toxicity
• Tincture of iodine
– alcoholic solution containing 5% iodine and 4%
potassium iodide
– potassium iodide inhibits formation of toxic
hypoiodides
– degraded when exposed to light
– the solution gets lighter
• Lugol's iodine
– 5% iodine dissolved in potassium iodide
– antithyroid effect
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• Povidone-iodine
– water soluble iodine complex of
polyvinylpyrrolidone
– surgical antiseptic
– also used for wounds and vaginal irrigation
• Povidone-iodine
– causes local reddening and burning sensation in
the skin
– liberates histamine from mast cells
– alcoholic solutions may irritate mucous
membranes
– iodine may cause allergy and anaphylaxis
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• Chlorine
– gaseous
– used to sterilize water
– hypochlorous acid is formed and disintegrates to
hydrochloric acid and oxygen
– more active at higher temperatures
– damages metals, plastics, rubber and textiles
– precipitates on surface of large dirt crumbs
• Hypochlorites
– damage bacterial membranes
– form chloramines with amino groups of proteins
– bactericidal, sporocidal, virucidal
• Bleaching powder
– calcium hypochlirote
– badly damages tissues
– used for walls, lavatories, pools, water
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• Sodium hypochlorite
– used for wounds with boric acid
– explosive if mixed with formalin
• Chloramine B
– benzene derivative
– more stable, less toxic
– chlorogen, halazone
• Sodium dichloroisocyanuric acid
– pH should be set to 6.2-6.8
– release corrosive chlorine gas at lower pH
• Bactericidal, virucidal, fungicidal
• Large quantities of organic material
compromises effectivity
• Corrosive
• Hydrogen peroxide
– catalase releases nascent oxygen
– short lasting effect
– inactivated by trace heavy metals
– corrosive for metals
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• Hydrogen peroxide
– 0.3-3% for contact lenses, throat, ears, eyes and
wounds
– if used in body cavities, resulting gases have to be
drained
– 10% solution is coagulant
– 30% is astringent
– crystals formed with urea are sold in tablets for
solution
– stabilized and combined with detergents is used
for instruments
• Peroxyacetic acid
– instable
– corrodes brass, iron and zinc
• Potassium permanganate
– 0.1-0.5% solution
– colours tissues
– used for wounds
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• Mercury
– reacts with thiol groups of proteins
– inactivates enzymes and precipitates proteins
• Inorganic compounds are obsolete
– damage host proteins, too
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mercuric chloride (corrosive sublimate)
mercuric oxide
mercuric cyanide
mercuric amidochloride
mercuric sulfide
• Organic mercury compounds
– less toxic
– antifungal
– spermicide
– active against Trichomonas
– toxic effects may be treated with glutathione or
cysteine
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• Phenylmercuric borate
– 0.02% for skin and mucous membranes
• Thiomersal
– ethylmercuric thiosalicylilate sodium
• Merbromin
– dibromhydroxymercuric fluorescein sodium
• Silver
– silver ions damage tissues and precipitate proteins
– protein bound and colloidal silver is less toxic
• Silver nitrate
– astringent and wound treatment
• Silver acetate
– 1% eyedrop for newborns against gonorrhoea
– now obsolete
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• Clean surfaces and promote penetration of
antiseptics
• Anionic detergents
– sodium or potassium salts of fatty acids
– alkaline when dissolved in water
– irritate skin
– no antiseptic effect
– used in combination
– inactivate cationic detergents
• Cationic detergents
– antiseptic properties
– bactericidal/bacteriostatic, antifungal
– increase permeability of plasma membranes
– most important ones contain quaternary nitrogen
– inactivated by anionic detergents
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• Cationic detergents
– adsorbed to fibrous, porous materials
– may be removed by such substances
– form film layer on the skin
– microbes may thrive under the film
– can be used to clean instruments and objects
• Benzalkonium chloride
• Cetylpyridinium bromide
• Non-ionic detergents
– no antiseptic activity
– do not inactivate cationic detergents
– used in combination
• Zwitterionic detergents
– also called amphoteric detergents
– positive and negative charge within the same
molecule
– antiseptic effect
– provide long lasting bacteriostatic and fungistatic
effect if dried on instrumets
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• Azo dyes
• Triphenylmethane dyes
– strong antiseptics
– organic materials inhibit their action
• Crystal violet
– hexamethyl pararosaniline chloride
– for wounds against Gram positive bacteria
– anthelmintic effect
• Fuchsine
– rosaniline hydrochloride
• Acridine dyes
• Proflavine
– for gums and throat
– mutagenic
• Acriflavine
– developed by Ehrlich against African Trypanosomiasis
• Methylene blue
– methylthioninium chloride
– urinary antiseptic
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• Sulfur
– fungicidal and parasiticidal
• Fatty acids
• Undecylenic acid, propionic acid
– antifungal activity
• Cleaning of objects from living pathogens, bacterial spores
and viruses
• Physical methods
• Heat
• Dry heat
– Incineration
– Hot air oven
• for glassware
– Pasteurization
• 30 min at 65°C, then 5 min at 85°C
– Boiling
• textiles
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• Moist heat
• Autoclave
– 20 min at 121°C on 107.8 kPa or 10 min at 134°C on 205.9
kPa
– saturated high pressure steam
– chemical and biological indicators are used to check
effectivity
• Filtration
– heat sensitive fluids
– 0.22 μm pores
• Chemical methods
• Gas sterilization
• Ethylene oxide
– heat-sensitive instruments, plastics, optical instruments,
transfusion instruments
– alkilates thiol groups of proteins
– flammable
– mixed with carbon dioxide or fluorinated hydrocarbons
– items should be wrapped prior to sterilization
– traces of the substance should be removed
– items are aired for days
– chemical and biological indicators are used
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