Chemistry in Everyday Life

1. Lec No 2 Contd
ANTISEPTICS AND
DISINFECTANTS
Dr.K.Parameswari, Dept of Chemsitry

2. Drugs
are complex molecules containing carbon, hydrogen with
some heteroatom like oxygen, nitrogen, sulfur.
On the basis of their action of different microorganism and
mode of action, drugs can be various types.
Some common classes of drugs are as follows.
Antipyretics: These drugs used to reduce fever.
Analgesics: They are painkiller which used to reduce pain
Antimalarial drugs: these drugs use to treat malaria
Antibiotics: They inhibited the germ growth which caused
disease
Antiseptics: They used to prevention of germ growth near
burns, cuts and wounds

8. COMMONLY USED TERMS
RELATED TO KILLING OF
MICROORGANISMS

9. ORIGINS OF ANTISEPTICS
Joseph Lister (1827 - 1912)
• Realised that deaths from operations mostly occurred
from infection contracted during the operation as a result
of unclean practices.
• He started using Carbolic acid (phenol) during operations
to maintain aseptic conditions with significant
improvements.
• Like Semmelweiss he initially encountered opposition,
but use of his methods by the Germans during the Franco-
Prussian war in 1870 provided his major breakthrough
and over the next 10 years, the practise of aseptic surgery
became accepted.

12. NATURAL ANTISEPTICS
•Lemon: The presence of citrus juice in lemon make it a good antiseptic which effect on
• immune function system, circulatory system and digestive systems. Because of its
antibacterial nature, it can use to sterilize the air by using few of its drops in a spray
bottle.
•Honey: it is a natural antiseptic which used to prevent the infection of wounds due to
presence of antibacterial agents which kill the bacteria present in and around the wound.
It can also be used for treating ulcers and burns, diarrhea and any vomiting and
stomach upsets.
•Pineapple: This fruit is rich in vitamin- A, C, and B, with manganese, which involve
• in metabolism of proteins and carbohydrates. Bromelain enzyme present in pineapple
is used for digesting proteins and enhances medical antibiotics due to its antibacterial
properties. Because of antiseptic and astringent nature of pineapple, it can used
treatment of pneumonia and infection caused by worms. It is also effective in the
treatment of kidney infections and kidney stones.
•Tea Tree Oil: it used for skin disinfectant like acne, athlete's foot and wound healing.
•Lavender: It is a natural antiseptic and astringent which helps with minor skin
problems.
•Eucalyptus: It has antiviral and antibacterial properties, thus used for the treatment of
flu, throat infections, sinusitis and headaches. Compare to natural antiseptic, synthetic
antiseptics are in much more uses due to their reactivity towards bacteria.

16. Common ANTISEPTICS

19. IODINE One of the oldest and most effective germicidal agents.
It inhibits protein synthesis and oxidizes –SH groups of amino acids. Also
Halogenates tyrosine in protein. Tincture of Iodine (2% I2+2% Na2I in 70%
alcohol) is a commonly used antiseptic for wounds.
Ethanol/SD Alcohol, 40 1–3%; fluid that acts as sanitizer.
Isopropyl alcohol, 1–2%; partly responsible for Lysol's strong
odor; acts as sanitizing agent and removes odor. p-Chloro-o-
benzylphenol, 5–6%; antiseptic.

24. Disinfection
DISINFECTANTS are chemical agents that inhibit
or kill microorganisms (surgical apparatus,
periphery of the patient, and the objects used by
the patient).
Disinfectants are used to kill bacteria. They are
used to sterilize instruments, utensils, clothes,
floors, sanitary fittings, sputum and excreta. They
harm the living tissues and cannot be used on
skin. Some examples are phenol, methyl phenol,
hydrogen peroxide and sulfur dioxide

26. When the concentration is less, it is an antiseptic and
when the concentration is more, the substance acts as
disinfectant.
For instance, 0.2% solution of phenol is an antiseptic
and 1.0% solution of phenol is a disinfectant.
Povidon iodine (A complex of I with polivinyl pyrrolidone-
surface active agent-). Can be used as antiseptics or
disinfectants.
Kill vegetative bacteria, mycobacteria, fungi, lipid
containing viruses. They kill spores as well on prolonged
use
Disinfectant can be used as Antiseptics
• Disinfectant and Antiseptics

27. CHLORINE
Chlorine is a strong oxidizing agent. Hypochloric
acid and sodium hypochlorite (household bleach
5.25%) are bactericidal and effective
disinfectants
10dilutions it provides 5000 ppm of chlorine. This
is the concentration recommended for
disinfection of blood spills. Dilutions are made
with tap water and when the opaque bottle is
tightly closed it preserves its activity.

28. < 5 ppm kills vegetative bacteria
5000 ppm is needed to kill spores
1000-10,000 ppm is tuberculocidal
100 ppm kills vegetative fungal cells in 1 h
500 ppm kills fungal spores
200-500 ppm inactivate viruses
HOCl is the active form, pH↑ less active OCl- is
formed→blood serum feces protein containing
materials should be removed from surfaces

29. ACTIVITIES OF DISINFECTANTS

31. Application of Disinfectants
• Food industry – sanitize food preparation areas,
preservative functions
• Drinking water – typically chlorine, other organic
oxidizers
• Medical – sterilization of equipment, facilities
• Household – cleaners (kitchen, bathroom, multipurpose),
soaps, detergents
• Other industries – paints, inks, cosmetics (serves as
preservative)