2. disinfectant
is a compound that is used to kill microorganisms in an inanimate
environment.
antisepticis one that is used to inhibit bacterial growth both in
vitro and in contact with the surfaces of living tissues.
Sterilants kill both vegetative cells and spores when applied to
materials for appropriate times and temperatures.
A.Alcohols, Aldehydes, and Acids:
1:Ethanol (70%) and isopropanol (70–90%) :are effective skin antiseptics
because they denature microbial proteins.
2:Formaldehyde,which also denatures proteins, is too irritating for
topical usebut is a disinfectant for instruments.
3: Acetic acid (1%) is used in surgical dressings and has activity against
gram-negative bacteria, including Pseudomonas, when used as a
urinary irrigant and in the external ear, Salicylic acid and undecylenic
acid are useful in the treatment of dermatophyte infections.
3. B. Halogens:
Iodine tincture: is an effective antiseptic for intact skin, it can cause
dermatitis, is commonly used in preparing the skin before taking blood
samples.
Iodine complexed with povidone (povidone-iodine): is widely used,
particularly as a preoperative skin antiseptic, but solutions can become
contaminated with aerobic gram-negative bacteria.
Hypochlorous acid: formed when chlorine dissolves in water,is
antimicrobial.
This is the basis for the use of chlorine and halazone in water
purification.
Many preparations of chlorine for water purification do not eradicate all
bacteria or entamoeba cysts.
Sodium hypochlorite: is the active component in household bleach,
a 1:10 dilution of which is recommended by the Centers for Disease
Control and Prevention (CDC) for the disinfection
of blood spills that may contain HIV or hepatitis B virus (HBV).
4. C. Oxidizing Agents:
1:Hydrogen peroxide: exerts a short-lived antimicrobial action through
the release of molecular oxygen. The agent is used as a mouthwash, for
cleansing wounds, and for disinfection of contact lenses.
2:Potassium permanganate is an effective bactericidal agent but has
the disadvantage of causing persistent brown stains on skin and
clothing.
D. Heavy Metals:
1:Mercury and silver : precipitate proteins and inactivate sulfhydryl
groups of enzymes but are used rarely because of toxicity.
Organic mercurials such as nitromersol and thimerosal frequently cause
hypersensitivity reactions but continue to be used as preservatives.
2:Merbromin :is a weak antiseptic and stains tissues a bright red color.
3:Silver sulfadiazine (a sulfonamide) is used to decrease bacterial
colonization in burns.
5. E. Chlorinated Phenols:
1:phenol itself is used only as a disinfectant of inanimate objects.
Mixtures of phenolic derivatives are used in antiseptics but can cause
skin irritation.
2:Hexachlorophene: has been widely used in surgical scrub routines and
in deodorant Soaps.
Repeated use on the skin in infants can lead to absorption of the drug,
resulting in CNS white matter degeneration.
3:Chlorhexidine is mainly active against gram-positive cocci and is
commonly used in hospital scrub routines to cleanse skin sites.
All antiseptic soaps may cause allergies or photosensitization.
6. F. Ectoparasiticides:
1:Lindane: is used to treat infestations with mites or lice and is also an
agricultural insecticide,The agent can be absorbed through the skin; if
excessive amounts are applied, toxic effects, including blood dyscrasias
and convulsions, may occur.
2: Crotamiton :is a scabicide with some antipruritic effects, which can be
used as an alternative to lindane. Allergic contact hypersensitivity may
occur.
3:Permethrin: is used topically in pediculosis and scabies;
The organophosphate cholinesterase inhibitor malathion is also used
topically in pediculosis.
G. Cationic Surfactants:
Benzalkonium chloride and cetylpyridinium chloride are used
as disinfectants of surgical instruments and surfaces such as floors and
bench tops.
Because they are effective against most bacteria and fungi and are not
irritating, they are also used as antiseptics.
