Chemicals in medicines
Chemical substances
used for treatment of disease and for reducing the suffering from pain are
called medicines or drugs. Chemotherapy is the science in which chemicals are
used for the treatment of diseases.
Chemicals used in chemotherapy are
frequently classified according to their action. Thus analgesics relieve pain,
antipyretics reduce temperature, anti-inflammatories control inflammation and
antibiotics kill bacteria and other micro-organisms.
Antipyretics
Antipyretics
are substances used to bring down body temperature in high fever. e.g. Aspirin,
Phenacetin and Paracetamol.
Aspirin is a common antipyretic. It
should not be taken empty-stomach as it generates salicylic acid which may
ulcerate stomach wall and can cause bleeding. Calcium and sodium salts of
aspirin are more soluble and less harmful.
Analgesics
There are drugs used
for relieving pain. Aspirin and some other antipyretics act as analgesics also.
Certain narcotics (which produce sleep and unconsciouness) are also used as
analgesics. Examples of narcotics are morphine, marijuana, codeine pethidine
and heroin. They are known to be habit-forming.
Antibiotics
Antibiotics are chemical substances produced
by micro-organisms (bacteria, fungi and moulds) that can inhibit the growth or
even destroy other micro-organisms. Penicillin is used against large number of
infections caused by various bacteria. It is an effective drug for pneumonia,
bronchitis, sore throat and abcesses. Other antibiotics like streptomycin and
tetracycline are used against diseases caused by bacteria.
Some antibiotics are specific for
certain diseases, for example, streptomycin for tuberculosis and
chloramphenicol for typhoid.
Broad spectrum antibiotics are medicines
effective against several different types of harmful micro-organisms, e.g.,
tetracycline, chloramphenicol. Penicillin has a narrow spectrum. Ampicillin and
amoxicillin are derivatives of penicillin.
Chloramphenicol is a broad spectrum
antibiotic. It is rapidly absorbed from the gastro-intestinal tract and hence
can be given orally in case of typhoid, dysentry, acute fever, certain form of
urinary infections, meningitis and pneumonia.
Sulpha drugs like sulphanilamide,
sulphadiazine and sulphaguanidine act against micro-organisms like antibiotics
and have been used in place of them.
Tranquillizers
The chemical substances which act on the
central nervous system and has a calming effect to reduce anxiety are specified
as tranquillizers. They are used for the treatment of mental diseases
they are also used for making sleeping pills. They are habit forming and should
not be taken without proper prescription. They do not add any energy into the
person but help to remove the emotional distress or depression and the person
is able to work to his full capacity. The most commonly used transquillisers
are barbituric acid and its substituted derivatives such as luminal and
seconal.
Chemical in food
During
processing of food a number of chemicals are added to it to increase its life
and also to make it more attraction. Some of these chemicals which are present
in food are discussed below.
1. Chemical preservatives : Growth of micro organisms in a
food material can be inhibited by adding certain chemical substance. Such
chemical substances which are added to food materials to prevents their
spoilage are known as chemical preservatives. The most commonly used
preservatives includes table salt, sugar, vegetable oils and sodium benzoate.
Sodium benzoate is used in limited quantities salts of sorbic acid and
propanoic acid are also used as preservatives.
2. Artificial
sweetening agent : Sugar is the natural sweeting agent however excess of
sugar leads of many diseases such as obesity, diabetes. Many artificial
sweetening agents have been isolated which are more sweeter than sugar.
Ortho-sulphobenzimide also called saccharin is the first popular sweetening
agent. Some other artificial sweetener are aspartame, sucrolose, alitame etc.
Cleansing agent
Two
types of detergents are used as cleansing agent. These are soaps and synthetic
detergents. These help in removal of fats which bind other materials to the
fabric or skin.
These
days detergents are much in vogue and get preference over soaps because they
work even in hard water. Synthetic detergents are classified into three main
categories namely anionic, cationic and non-ionic and each category has its
specific use detergents with straight chain of hydrocarbons are preferred over
branched chain as the latter are non-biodegradable and consequently cause
environmental pollution.
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