CONSIDERATIONS IN

SELECTION OF
ANTISEPTICS AND
DISINFECTANTS
FOR VETERINARY
DISPENSARIES
 Introduction
 Antiseptics are used in surgery for antisepsis of
the surgical site, surgeon’s hands
 disinfect surgical instruments, apparel, and
hospital premises.
 Other common uses are as disinfectants for home
and farm premises, food processing facilities, in
water treatment, in public health sanitation
 As antiseptics in soaps, teat dips, dairy sanitizers,
 The same compound -AS or DIS, dep.on conc.,
conditions of exposure, number of organisms, etc.
 Maximal efficiency- proper concentration of the
agents for the purpose intended
 Selecting antiseptics/disinfectants
Three factors are to be considered
 the type of microorganism the agent has
to eliminate(bacteria, virus, fungi or
vegetative or spore forms)
 the environment in which the agent will be
used (living tissue/inanimate, presence or
absence of dirt/debris)
 the characteristics of agent(corrosiveness,
cost and antimicrobial spectrum)
 Classification
Physical agents
 Moist Heat- –Boiling water & autoclaving
 Pasteurization
 Dry heat- –Flaming,, Incineration,, Baking in
oven
 Filtration
 Radiation - Ionizing –X-rays and gamma
rays; Non-ionizing –UV and infrared light
 Ultrasonic Vibrations
Chemical Agents
1. Acids and alkalies
boric acid, benzoic acid, NaOH Na2CO3 quick lime(CaO)
2. Halogens- iodine Iodophores Chlorine, bromine
3. Alcohols- ethyl alcohol(70%), isopropyl alcohol (50%),
benzyl alcohol
4. Phenols and Phenolics
phenol, cresol, lysol, hexyl resorcinol, hexachlorophene,
chloroxylenol
5. Heavy Metals and their compounds
mercuric chloride, merchurochrome, AgNO3, ZnO, CuSO4
6. Oxidizing agents
H2O2, KMnO4, Zn permanganate, sodium perborate,
benzyl peroxide
7. Reducing agents/ Alkylating agents-
formaldehyde, ethylene oxide(gas),
glutaraldehyde
8. Dyes
acriflavine, euflavine, proflavine, gentian violet,
crystal violet, methylene blue, brilliant green,
fluorescein dye, aminocrine
9. Detergents/surfactants/ Wetting
agents/Cleansers
cationic(Quaternary ammonium compoumnds-
benzalkonium chloride, benzethonium chloride,
cetrimide, acertyl pyridinium chloride)
anionic (soaps)
nonionic ( amphoteric)
10. Miscellaneous /Biguanides- chlorhexidine HCl
 Alcohols
 Ethyl alcohol (70% ethanol)
 isopropyl alcohol (50% isopropanol)
 Isopropanol is slightly more potent than ethanol
 As a skin disinfectant and rubefacient.
 Alcohol-based hand rinses have rapid-acting
antiseptic effects
 Wide germicidal activity,non corrosive, but-fire
hazardous risk
 Limited residual activity due to evaporation
 Limited activity in the presence of organic matter
and not effective against bacterial or fungal
spores
 Acids and Alkalies
 Strong mineral acids (HCl, H2SO4, etc) in
concentrations of 0.1-1 N
 Corrosive action limits their usefulness
 Acids as food preservatives-, benzoic acid,
antiseptics (eg, boric acid, acetic acid), fungicides
(eg, salicyclic acid, benzoic acid)
 Acetic acid, 1%, used in surgical dressings, and
0.25% acetic acid is a useful antibacterial agent for
irrigation of the urinary tract.
 At 5%, it is bactericidal to many bacteria and has
been used to treat otitis externa produced by
Pseudomonas , Candida , Malassezia , or Aspergillus
spp.
 Acids and Alkalies…contd
 Hydroxides of sodium and calcium used as
disinfectants
 their caustic property usually limits their
application on tissues.
 A 2% solution of soda lye (contains 94%
sodium hydroxide in hot water) used is a
potent caustic
 Calcium oxide , ie, lime (hydrated or air-
slaked lime), soaked in water produces
Ca(OH)2. are used to disinfect premises
 Chlorhexidine
 potent activity against gram-positive, some gram-negative
bacteria but not against spores
 activity is enhanced by alcohols, quaternary ammonium
compounds, and alkaline pH,
 depressed by high concentrations of organic matter (pus,
blood, etc), hard water, and contact with cork.
 incompatible with anionic compounds, including soap
 4% emulsion of chlorhexidine gluconate is used as a skin
cleanser,
 0.5% (w/v) solution in 70% isopropanol as a general
antiseptic
 0.5% solution in 70% isopropanol with emollients as a hand
rinse.
 Chlorhexidine-alcohol mixtures are particularly effective in
that they combine the antiseptic rapidity of alcohol with the
persistence of chlorhexidine.
 low potential for systemic/ dermal toxicity --shampoos,
ointments, skin and wound cleansers, teat dips etc
Hydrogen peroxide: (3%)
 Effervescent action (liberates oxygen when in
contact with catalase present on wound surfaces)
helps to remove pus and cellular debris from
wounds
 cleaning and deodorizing infected tissue.
 action is of short duration and is limited to the
superficial layer of the applied surface, no
penetration of the tissue.
Benzoyl peroxide
 cause skin irritation
 keratolytic and antiseborrheic activity
 treating pyoderma in dogs
Potassium permanganate
 is an effective algicide (0.01%) and
virucide (1%) for disinfection
 concentrations >1:10,000 tend to irritate
tissues.
 Staining of tissues is disadvantage.
 Chocolate brown coloured old solutions
indicate the loss of activity
 Iodine
 Elemental iodine is a potent germicide with a
wide spectrum of activity and low toxicity to
tissues.
 Poorly soluble in water but readily dissolves
in ethanol, which enhances its antibacterial
activity
 Tincture iodine (strong/weak)
 Wide germicidal activity including fungi and
bacterial spores, characteristic odor
 corrosive and has limited activity in the
presence off organic matter
 Iodophores
 povidone-iodine
 slowly release iodine as an antimicrobial agent
 do not sting ,stain. nontoxic to tissues but may be
corrosive to metals.
 Effective against bacteria, viruses, and fungi but
less so against spores.
 Good antibacterial activity even in the presence of
organic matter
 Change color when the activity is lost.
 Phosphoric acid is often mixed with iodophores to
maintain an acidic medium.
 Used in teat dips, dairy sanitizers and for various
dermal and mucosal infections
 Chlorine
 potent germicidal effect against most bacteria,
viruses, protozoa, and fungi ( 0.1 ppm)
 Much higher conc. in presence of organic matter.
 strong acid smell, is irritant to the skin and mucous
membranes.
 Used to disinfect water supplies ,inanimate objects
(eg, utensils, bottles, pipelines) in dairies.
 Inorganic chlorides include sodium hypochlorite
(Dakin's solution) solutions (bleach)and calcium
hypochlorite.
 Chlorinated lime (bleaching powder): mixture of
calcium hypochlorite and calcium chloride; for
disinfection of water, livestock premises,
destruction and disposal of carcasses ,elimination of
pathogens from organic matter
Phenol (carbolic acid)
 bacteriostatic at 0.1-1%;s bactericidal/fungicidal
at 1-2%. T
 Activity enhanced by warm temperatures
 Decreased by alkaline medium, lipids, soaps, and
cold temperatures.
 5% solution - strongly irritating, corrosive to
tissues.
 Oral ingestion/ excess application to skin can
cause systemic toxicity.
Cresol : 2% solution of either pure or saponated
cresol (Lysol) in hot water is a disinfectant for
inanimate objects
Formaldehyde
 1-10% solution used as a disinfectant
Glutaraldehyde
 1-2% alkaline solution (pH 7.5-8.5) in
70% isopropanol is a more potent
germicide than 4% formaldehyde.
 used to sterilize surgical and endoscopic
instruments and plastic and rubber
apparatus
 Teat dips
 Soaps
 Anionic detergents which emulsify lipoidal
secretions of the skin
 Remove, along with most of the accompanying
dirt, desquamated epithelium and bacteria,
which are then rinsed away with the lather.
 The antibacterial potency: enhanced by
inclusion of certain antiseptics, eg,
hexachlorophene, phenols, carbanilides, or
potassium iodide.
 They are incompatible with cationic surfactants
 Cationic detergents
 Quaternary ammonium compounds (eg, benzalkonium
chloride, benzathonium chloride, cetylpyridinium chloride, cetyl
pyridinium bromide/cetrimide)
 Activity is reduced by porous or fibrous materials (eg, fabrics,
cellulose sponges) that adsorb them
 Inactivated by anionic substances (eg, soaps, proteins, fatty
acids, phosphates).
 Limited value in presence of blood and tissue debris.
 Effective against most bacteria, some fungi , protozoa but not
against viruses and spores.
 Aqueous solutions of 1:1,000 to 1:5,000 have good
antimicrobial activity, especially at slightly alkaline pH.
 When applied to skin, they may form a film under which
microorganisms can survive, which limits their reliability as
antiseptics.
 Concentrations >1% are injurious to mucous membranes
Chloroxylenols
 Parachlorometaxylenol ,dichlorometaxylenol
 broad-spectrum with more activity against
gram-positive than gram-negative bacteria.
 Active in alkaline pH; however, contact with
organic matter diminishes their activity.
 5% chloroxylenol solution (in α-terpineol,
soap, alcohol, and water) is diluted with
water (1:4) for skin sterilization
 1:25 to 1:50 for wound cleansing and
irrigation of the uterus and vagina
 Preferred antiseptics
 with antifungal activity
phenols, chlorhexidine , iodine,
povidoneiodine,hypochlorite,cetrimide
 with antviral activity
isopropanol,ethanol,formaldehyde
glutaraldehyde,sodium hyopochlorite,phenol,
potassiumpermanganate,hydrogen peroxide,
iodophors
 Recommended antiseptics/disinfectants for
hospital situations
 All the instruments have to be immersed for 30 mins and rinsed
and autoclaved.
 2% sodium hypochlorite: for gloves, syrienges, needles , blood
spills on floor, floor washing. lab glasswares
 2% benzalkonium chloride: foreceps, thermometer
 2% glutaraldehyde: Instruments-catheters, laryngoscope,
endotracheal tubes
 6% hydrogen peroxide: removal of blood clots from
tubes,catheters, dressing wounds
 Benzalkonium chloride: hand wash, foreceps, catheters ,
instruments
 Phenol: disinfecting toilets
 Povidone iodine: surgical scrub, painting skin, dressing, hand
wash
 Ethyl alcohol: antiseptic at injection site, furniture disinfection