ANTISEPTICS AND

DISINFECTANTS

DR KAMAL OJAH

PGT, DEPT. OF PHARMACOLOGY

These are chemical substances which inhibit the growth or kill microorganism on living surfaces such as skin & mucous membrane.

ANTISEPTICS

These are chemical substances which inhibit the growth or kill microorganism on inanimate objects such as instruments.

DISINFECTANTS

Characteristics of an ideal antiseptics/disinfectants

• Chemically stable• Cheap• Nonstaining• Cidal, destroying spores as well.• Active against all pathogens• Require brief time of of exposure• Active even in presence of blood, pus, exudates

and excreta.

An antiseptics in addition

• Rapid in action & exert sustained protection.

• Nonirritating to tissues.

• Nonabsorbale , produce min. toxicity if absorbed.

• Nonsensitizing

• Earliest used , reference standard• Protoplasmic poison• Injures tissues & cells at high conc.

• Denauration of bacterial proteins• To disinfect urine , faeces , pus.

PHENOL

• Methyl derivative of phenol

• Less damaging to tissues than phenol.

• 3-10 times more active

• Use for disinfection of utensils , excreta & for washing hands.

CRESOL(Lysol)

• Phenol derivative• Doesnot coagulate proteins• Noncorrosive, nonirritating to skin• Commercial 4.8% solution used for surgical

antiseptics• Skin cream and soap 0.8%• Mouth wash 1%

CHLOROXYLENOL(Dettol)

Pot. permanganate• Purple crystals ,highly water soluble , liberates

oxygen

• Action is slow, high conc. cause burns

• Used for gargling ,irrigating cavities & wounds

• Also used to disinfect water in ponds

OXIDIZING AGENTS

• Liberates nascent oxygen which oxidizes necrotic matter & bacteria.

• Helps in loosening & removing slough, ear wax

HYDROGEN PEROXIDE

• Iodine • Iodophores• Chlorine• chlorophores

HALOGENS

• Rapidly acting , broad-spectrum agent.• Acts by iodinating and oxidizing microbial

protoplasm• Use for cuts, degerming skin before surgery.• High conc. cause burns.

IODINE

• Soluble complexes of iodine. • Known as povidone iodine.• Nonirritating, nontoxic,nonstaining & exerts

prolonged grmicidal action.• Used on boils, furunculosis, burns ,ulcers ,

tinea,nonspecific vaginitis, disinfection of endoscope.

IODOPHORES

• Rapidly acting potent germicide.

• 0.1-0.25 ppm kills most pathogen in 30 secs.

CHLORINE

Chlorinated lime(bleaching powder)

• Obtained by action of chlorine on lime

• Use to disinfect drinking water, swimming pools

CHLOROPHORES

Sod. Hypochlorite :

• Powerful disinfectant used in dairies for milk cans.

• Too irritant to be used as anticeptics except in root canal therapy.

CHLORHEXIDINE• Acts by disrupting bacterial cell membrane &

denaturation of bacterial proteins.

• Nonirritant , more active against gram+ve bacteria

• Used in surgical scrub, neonatal bath, mouth wash & general skin anticeptics.

BIGUANIDES

CETRIMIDE:• Detergent action • Cidal to bacteria• Act by altering permeability of cell membrane.• Widely use as anticeptics & disinfectant for

surgical instruments.

QUATERNARY AMMONIUM ANTICEPTICS

ETHANOL:• Antiseptic ,cleansing agent at 40-90% conc.

• Acts by precipitating bacterial proteins.

• Irritant, should not be applied on mucous membrane, ulcers, open wounds.

ALCOHOL

• Use for fumigation• 37% aqueous solution is called formalin.• Protoplasmic poison , denatures protein.• Use for preserving dead tissues• Use as antiseptics is restricted due to bad

odour

FORMALDEHYDE

• Less pungent, less irritant

• Broad spectrum activity

• 2% solution (cidex) use to disinfect surgical instruments & endoscopes.

GLUTARALDEHYDE

BORIC ACIDS :• Weak antiseptics , bacteriostatic

• Use for mouth wash , irrigation of eyes , glossitis

• Vomiting , abdominal pain , diarrhoea on systemic absorption.

ACIDS

SILVER COMPOUNDS :

• Silver sulfadiazine is active against pseudomonas infection.

• Silver nitrate is highly active against gonococci

METTALIC SALTS

Gentian violet :• Active against gram +ve bacteria , fungi

• Use on chronic ulcers , bedsores , furunculosis, ring worm.

DYES

ACRIFLAVINE :

• Active against gram +ve bacteria, gonococci

• Store in amber colored bottle.

• Nonirritant

• Use chronic ulcers and wounds

THANK YOU