Disinfectants Antiseptics

7/23/2019 Disinfectants Antiseptics

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Gabor Pozsgai MD.

Faculty of Medicine University of Pcs

2012

Inhibition of pathogen cell division

Elimination of pathogens


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Antimicrobial drugs

chemoterapeutics

may be given systemically

Disinfectants and antiseptics

cannot be used systemically

Urinary antiseptics are given systemically, butexert 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

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 m

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

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 toxichypoiodides

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 mucousmembranes

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 materialcompromises 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 andwounds

if used in body cavities, resulting gases have to bedrained

10% solution is coagulant

30% is astringent

crystals formed with urea are sold in tablets forsolution

stabilized and combined with detergents is usedfor 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

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 ofantiseptics

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 samemolecule

antiseptic effect

provide long lasting bacteriostatic and fungistaticeffect 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 sporesand viruses

Physical methods

Heat

Dry heat Incineration

Hot air oven for glassware

Pasteurization 30 min at 65C, then 5 min at 85C

Boiling textiles


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Moist heat

Autoclave 20 min at 121C on 107.8 kPa or 10 min at 134C on 205.9

kPa

saturated high pressure steam

chemical and biological indicators are used to checkeffectivity

Filtration heat sensitive fluids

0.22 mpores

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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Disinfectants Antiseptics