2. Sterlization
• Freeing of an article, surface or medium by
removing or killing all micro-organisms
including vegetative form of
bacteria, spores, viruses, fungii
3. Disinfection
• Destruction or inhibition of growth of all
pathogenic organisms (bacteria, viruses,
fungii) on non living surfaces
• If spores are also killed process is Sterlization
4. Antiseptics
• These are chemical substances
which inhibit the growth or kill micro-
organisms on living surfaces such as skin &
mucous membrane.
5. Properties of good antiseptic/
disinfectant
1. Cidal
2. Non staining & good odour
3. Active against all pathogens
4. Active in presence of pus, blood & exudates
5. Rapid acting
6. Non irritating to tissues / non corrosive
7. Non absorbable
8. Non sensitizing/
6. Mechanisms of action of antiseptic
and disinfectants
• Oxidation of bacterial protoplasm
– Potassium permagnate, H202, Halogens
• Co-agulation (denaturation) of bacterial
proteins & disrupt cell membrane
– Phenols, chlorhexidine, alcohols, aldehydes
• Detergent like action ↑ permeability of
bacterial cell membrane
– Cetrimide, soaps
9. CRESOL (Lysol)
• Methyl Derivative of phenol, less damaging
to tissues than phenol.
• 3-10 times more active
• used for disinfection of utensils, excreta &
for washing hands.
10. Chloroxylenol (Dettol)
• Phenol derivative
• Does not co-agulate proteins,
• Non corrosive,Non irritating to skin
• Commercial 4.8 % solution used for surgical
antisepsis
• Skin cream and soap: 0.8%
• Mouth wash 1%
11. Hexachlorophene
• Commonly incorporated in soap
• Effectively only against Gm+ve
• Slow but persistant action
• >2% preparations banned
12. Oxidizing agents
• Potassium permagnate:
– Purple crystals, highly water soluble, liberates
oxygen which oxidizes bacterial protoplasm.
– Used for gargling, irrigating wounds, urethra
(condy`s lotion diluted solution of 1:4000 to
1:10,000 )
– High conc cause burns
– It is also used to disinfect water in ponds.
– Stomach wash in alkaloidal poisoning
13. Oxidizing agents
Hydrogen Peroxide
– liberates nascent oxygen which oxidizes necrotic
matter & bacteria.
– Helps in loosening & removing slough, ear wax
etc.
Benzoyl Peroxide
– Widely used drug for acne.
– liberates O2 in presence of water which kills
bacteria, specially anaerobes
15. Iodine
• Rapidly acting broad spectrum
(bacteria, fungi,virus)
• Acts by iodinating and oxidizing microbial
protoplasm.
• Used for cuts, degerming skin beforesurgery.
• Adverse effect: cause burns & blisters
16. Iodophores
• Known as povidine iodine.
• Non toxic, non staining prolonged action.
• Used on
boils, furunculosis, burns, ulcers, tinea, surgica
l srub, disinfecting surgical instruments, non
specific vaginitis.
17. Chlorine
• potent germicide. Kills pathogens in 30 sec.
used to disinfect urban water supplies.
• 0.1 to 0.25 ppm
18. Cholorophores
(1) Chlorinated lime (bleaching powder)
– obtained by action of chlorine on lime.
– used to disinfect drinking water
(2) Sodium hypochlorite
– Powerful disinfectant used in dairies for milk
cans.
– Too Irritant to be used as antiseptic.
– Root canal therapy in dentisry
19. Biguanides
Chlorhexidine: (Savlon)
– Acts by disrupting bacterial cell membrane &
denaturation of bacterial proteins
– Non irritant ,more active against gram +ve
bacteria.
– Used in for surgical scrub, neonatal bath, mouth
wash & general skin antiseptic.
– Most widely used antiseptic in dentisry 0.12-0.2%
oral rinse or 0.5 -1 % tooth paste
20. Quarternary ammonium antiseptics
cetrimide
• Detergents: Cidal to bacteria, fungi & viruses.
• Act by altering permeability of cell membrane
• Efficiently remove dirt and grease
• Widely used as antiseptics & disinfectants for
surgical instruments, gloves etc
• Combined with chlorhexidine (savlon)
21. Soaps
• Anionic detergents
• Weak antiseptics with cleansing action
• Washing with soap and warm water one of
the most effective methods of preventing
disease transmission
• Affect only Gm+ bacteria
22. Alcohols
• Ethanol
– Antiseptic, cleansing agent at 40-90% conc.
– Act by precipating bacterial proteins
– Irritant, should not be applied on mucous
membrane, ulcers, open wounds.
23. Aldehydes (Formaldehyde)
• Used for fumigation.
• 37 % aqueous solution called as formalin.
• Protoplasmic poison , denaturates protiens.
• Used for preserving dead tissues.
• Use as antiseptic restricted due to bad odour
& irritation
• Glutaraldehyde is a better sterlizing agent
24. Acids
Boric acid
• weak antiseptic , bacteriostatic.
• used for mouth wash, irrigation eyes, glossitis.
• Adverse effect: vomiting ,abdominal pain on
systemic absorption.
25. Metallic salts
SILVER COMPOUNDS
• Silver sulphadiazine is active against
pseudomonas seen in burns patient.
• Silver nitrate highly active against gonococci
ZN SALTS
• Mild antiseptic, used as eye wash, ear drops.
26. Dyes
Gentian violet:
– Active against bacteria (gram + ve), fungi
– Used on chronic ulcers, furunculosis, bed sores,
ring worms.
Acriflavine
– Active against gram +ve bacteria & gonocci
– suitable for chronic ulcers & wounds
– Do not retard healing, non irritant
27. Ectoparasiticides
• These are drugs used to kill parasites that live
on body surfaces
lice → cause pediculosis (hair infection)
mites → cause scabies(skin infection)
28. Drugs used are
(1) PERMETHRIN
(2) LINDANE
(3) BENZYL BENZOATE
(4) IVERMECTIN
(5) CROTAMITON
(6) SULFUR
29. Permethrin
• Broad spectrum causes neurological paralysis in
insects.
• 100 % cure rate nearly
• Single application needed in most cases.
• Few patients experience itching ,burning.
• first drug of choice for scabies & pediculosis.
Scabies: apply all over the body except face &
head . Wash after 8- 12 hrs.
Head louse: massage about 30 g in to scalp and
wash after 10 min.
30. Lindane
• Broad spectrum insecticide which kills lice and
mites by penetrating their chitinous cover
• Properties similar to permethrin.
• Cure rate low & resistance seen.
• Disadvantage: being lipid soluble CNS toxicity like
vertigo , convulsions seen.
• Application similar to permithrin.
• combination with benzyl benzoate is more
effective.
31. Benzyl benzoate
• Oily liquid with aromatic smell.
• Cure rate 76 – 100% ; second application required
after 24 hrs.
• Toxicity is low. Application similar to permethrin.
• Use has declined due to skin irritation.
• Contra indicated in children because of
neurological symptoms & skin irritation.
• combination with lindane highly effective.
32. Crotamiton
• low cure rates
• Better results if applied for 5 days in children
• Less irritation and toxicity
• May be preferred in children as second choice
33. Ivermectin
• Anti helminthic drug which has been recently
found effective against scabies & pediculosis.
• A single 0.2 mg /kg ( 12mg in adults) has 91-
100 % cure rate.
• Contra indicated in children 5yrs ,
preganant & lactating women.
Editor's Notes
Germicide is an agent which covers both these agents Seimelweiss: chlorinated lime. Lister: phenol
Chemically stable and cheap
Static in 0.2 & cidal in >1% concAccidental poisoning: rapidly absorbed penetrate intact skin, GIT corossion pain, collapse, decreased body temperature, convulsions and death by respiratory failure. Not used as antiseptoc due to corrosive nature
Wider margin of safety
0.8% skin cream and soap, 1.4% for mouth wash These preparations loose activity if diluted or kept in water for long period of time Loose activity if diluted in water and kept for long time
Around 1970 fatalities in US due to
includes k permanganate, H2O2 , benzoylperxide.Except atropine and cocaine which are not efficiently oxidized
Liberates nascent oxygen which oxidizes necrotic matter and bacteria 30 % solution produces 10 volumes of oxygen much of which escapes in molecular form Catalase present in tissue speeds decomposition resulting in faomoing and helps loosening and removing slough Benzoyl peroxide: induces desquamation, the comedones are shed & irritant fatty acids are reduced. Mild irritant, burning sensation is often felt .
Compounds that slowly release hypochorous acid
Prevention of gingivitisHow ever it may leave unpleasant taste and on repeated administration may cause brownish discoloration of teeth
Many gram negative bacteria like pseudomonas,mycobcaterium TB and spores are eresistantSoaps are anionic and neutralize their action while alcohol potentiates it, spread through oil and grease and cleansing properties
Can be medivcated by adding other antiseptics
Rapidity of action increases upto 70% and decreases above 90%Cotton swab soaked in 70% alcohol rubbed on skin kill 90% of bacteria in 2 min has been used before hypodermic injection
Diluted to 4 % and is used for hardening tissues Eczematoid reactions can reactions can occur
10% ointment borocide is available for cuts and abrasion Acetic acid is relatively weak antiseptic only above 5% pseudomonas is susceptible . It is occasionally used for sub burn dressing and for douche in 1-3 % strength s
mercuric compounds - poor antiseptic & bacteria spore survive after contact. Not used
Triple dye lotion contains gentian violet brilliant green and acriflavineTRIPLE DYE LOTION: Contain gentian violet + brilliant green + Acriflavin used for burns & dressing umblical stump in neonates
Maximum 92 % cure rate
For pediculosis it should be applied to scalp taking care not to enter the eyes and washed off after 24 hours now it is second choice drug for scabies and seldom used for pediculosis its combination with lindane is highly effective