17 chemistry in action 87-90

8/10/2019 17 Chemistry in Action 87-90

http://slidepdf.com/reader/full/17-chemistry-in-action-87-90 1/5

Chemistry in Action

Chemistry In Action1. DRUGS

• Drugs may be a single chemical substance or a combination of two or more dierent substances.

An ideal drug should satisfy the following requirements,

(a) When administrated to the ailing individual or host, its action should be localised at the

site where it is desired to act. In actual ractice, there is no drug which behaves in this

manner.

(b) It should act on a system with e!ciency and safety.

(c) It should have minimum side eects.

(d) It should not in"ure host tissues or hysiological rocesses.

(e) #he cell should not acquire resistance to the drug after sometime.2. ANALGESICS

• Drugs which relieve or decrease ain are termed analgesics. #hese are of two tyes,

(i) Narcotics $ #hese are mainly oium and its roducts such as morhine, codeine and

heroin. #hese roduce analgesia and slee and in high doses cause unconsciousness.

#hey are very otent drugs and their chronic use leads to addiction.

(ii) Non-narcotics $ #hese are the drugs which are not otent and do not cause addiction.

%ommon drugs are asirin and analgin. #hese drugs also have antiyretic roerties.

3. ANTISEPTICS AND DISINECTANTS

• Antise!tics " #he chemical substances which are used to &ill or revent the growth of micro'

organisms are called antisetics. #hese are not harmful to living tissues and can be safely

alied on wounds, cuts, ulcers, diseased s&in surfaces. #hese are also used to reduce odours

resulting from bacterial decomosition of the body or in the mouth. #hey are, therefore miedwith deodorants, face owders and breath uriers. We all must be familiar with antisetic

creams li&e furacin, soframycin etc.

• Disin#ectants " #he chemical substances which are used to &ill microorganisms but they cannot

be alied on living tissues are called disinfectants. #herefore, disinfectants also &ill micro

organisms but these are not safe for living tissues. Disinfectants lay a ma"or role in water

treatment and in ublic health sanitation. #hese are commonly alied to inanimate ob"ects

such as *oors, instruments, etc. #he same substance can act as disinfectant as well as

antisetic deending uon its concentration. +or eamle, a .- solution of !heno$ acts as

antisetic and its / solution acts as disinfectant.

#he common eamles are,

87

Analgin

CH0

NNC

H – C C

CH0

O

(CH0)

-CH–CH

- CHCOOH 1

CH0Ibuprofen

CH-COON

a

Diclofenac2odium

NH

Cl

Cl

H0CO

CHCOOH

CH0

Naproxen



Chemistry in Action

(a) %l- is used for ma&ing water t for drin&ing at a concentration .- to .3 m.

(b) Detto$ is an antisetic. It is a miture of chloroylenol and tereneol in a suitablesolvent. %hloroylenol has both antisetic and disinfectant roerties.

(c) Bithional is antiseptic which is generally added to medicated soaps to reduce the odour produced

by bacterial decomposition of organic matter on the skin.

(d) Io%ine is owerful antisetic. It is used as a tincture of iodine which is -'0 iodine

solution of alcohol'water.

(e) 4ow concentrations of s&$!h&r %io'i%e are used for sterili5ing and reservation of squashes.

(f) A dilute aqueous solution of (oric aci% is used as a wea& antisetic for eyes. It also

forms a art of antisetic baby talcum owders.

(g) Io%o#orm is also used as an antisetic owder for wounds.

(h) )y%ro*en !ero'i%e is also used as non'irritating strong antisetic.

(i) )e'ach$oro!hene is mainly used in soas, creams, dusting owders and emulsions.

(") Amy$ metacreso$ (6'methyl'-'entyl henol) is an antisetic which is used commonly

as a mouthwash or gargles in infections of the mouth and throat.

(&) A naturally occurring henol derivative, thymo$ is used as a owerful disinfectant than

henol.

(l) 2ome organic dyes are also eective antisetics. #hese are used for the treatment of

infectious diseases. #he common eamles of antisetic dyes are *ention +io$et and

methy$ene ($&e.

,. ANTIITICS

• A chemical substance roduced by or derived from living cells which is caable of inhibiting the

life rocesses or even destroying micro'organism is called

Anti(iotics.

• #he rst antibiotic, discovered by Aleander +leming in /7-7

from the mould enicillium notatum, was enicillin. In /708,

9rnst %hain and :oward +lorey isolated enicillin in ure

form and roved its eectiveness as an antibiotic. It was

introduced into medical ractice in /73/. ;enicillin is used

against large number of infections caused by various cocci,

gram ositive bacteria, etc. It is an eective drug for neumonia, bronchitis, sore throat and

abcesses.

2everal naturally occurring enicillins have been isolated all of these have the emirical

88

O

H

C

l

Cl

S

OH

Cl

Cl

<ithional

%hloroylenol

OH

Cl

H0C CH

0

Amylmetacresol

OH

CH0

C6H

/

/

#hymol

OH

H0

C

CH(CH0)

-

=eneral structure ofenicillin

O

NCH

CCNCR

HHO

OC

HC

C

S

CH0

O

H

CH0

>aline

%ysteine



Chemistry in Action

formula, RSNOHC -3//7

/. C)E0ICALS IN D

• ?any chemicals are added to food for their reservation and enhancing their aeal. #hese

include *avourings, sweeteners, dyes, antioidants, fortiers, emulsiers and antifoaming

agents. With the ecetion of the reservatives, fortifying agents, antioidants and articial

sweeteners, the remaining classes of chemicals mentioned above are added either for ease in

rocessing or for cosmetic uroses, in the real sense these have no nutritive value.

/.1 Antio'i%ants $ Antioidants are the imortant and necessary food additives. #hese

comounds retard the action of oygen on the food and thereby hel in its reservation.

#hese act as sacricial materials, i.e., these are more reactive towards oygen than are the

materials they are rotecting. #hey also reduce the rate of involvement of free radicals in the

aging rocess. #he two most familiar antioidants used are butylated hydroy toluene (<:#)

and butylated hydroy anisole (<:A). #he addition of <:A to butter increases its storage life

from months to years. #he two have the following structures.

• 2ometimes <:# and <:A are added in combination with citric or ascorbic acids to roduce a more

active synergietic eect. 2ulhur dioide and sulhite are useful antioidants for wine and

beers, sugars syrus and cut eeled or dried fruits and vegetables.

/.2 Preser+ati+es$ #he reservatives revent soilage of food due to microbial growth. #he most

common reservative used is sodium ben5oate, .6@ COONaHC It is metaboli5ed by

conversion to hiuric acid, COOHCONHCHHC -6@ which ultimately is ecreted in the

urine. 2alts of roionic acid and sorbic acid are also used as reservatives.

/.3 Articia$ seetener $ #he articial sweeteners are another tye of food additives.

Articia$

Seetn

er

Str&ct&ra$ orm&$aSeetenin*

In%e'

Asartam

e

0

AAA

A

A

-

A

AAAA

A

AA

CHO

O

H

C

H

C

C

H

H

N

NH

O

C

H

C

H

H

C

O

CHO −−−−−−−−−

/@

2acchari

n0

(H0C)

0

C

CH

3

OH

(<:#)

C(CH0)

0

OCH0

OH

(<:A)

C(CH0)

0

89

+romasartic acid +rom henylalanine

methyl ester

O

NH

SO2



Chemistry in Action

Dulcin

6

Alitame

HC

H

N

O

C

CH

H

C

H

N

NH

O

C

H

C

H

H

C

O

CHO −−−−−−−−−−

A

AA

0A

AA

-

A

AAAA

A

AA

-

#he rst oular articial sweetener was saccharin. It was mar&eted as its water soluble

sodium or calcium salt. 2accharin is aroimately 0 times sweeter than cane sugar. It has

roved to be a lifesaver for countless diabetics and is of great value to eole who need to

control inta&e of calories.

<esides saccharin, the other commonly mar&eted articial sweeteners are described here.

Asartame is unstable at coo&ing temeratures, limiting its use as a sugar substitute to cold

foods and soft drin&s. Alitame is more stable than asartame during coo&ing. Bne otential

roblem with alitame and similar tye of high'otency sweetners is the di!culty in controlling

sweetness of food. 2ucralose is redicted to become a great commercial success.

LASSROOM ASSIGNMENT

Q 1. Aspirin is

(a) Antibiotic

(b) Antipyretic (c) Sedatie (d) !sychedelic

Q 2. "hich of the following drugs is a tran#uili$er and sedatie

(a) Sulphadia$ine (b) !apaerine (c) %#uanil (d) &escaline

Q 3. 'he drug used as an antidepressant is

(a) uminol (b) 'ofranil (c) &escaline (d) Sulphadia$ine

Q 4. Salol can be used as

(a) Antiseptic (b) Antipyretic (c) Analgesic (d) None of these

Q 5. eroin is a deriatie of

(a) *ocaine (b) &orphine (c) *affeine (d) Nicotine

Q 6. "hich of the following is not antibiotic

(a) 'etracyclin (b) Neomycin (c) *arbomycin (d) *yclohexane

Q 7. "hich of the following is an antidiabatic drug

(a) Insulin (b) !enicillin (c) *hloro#uine (d) Aspirin

Q 8. "hich of the following is used as an antibiotic

90

C

CH0

CH0

C

S

CH0CH

0

NHCONH-

OC0H

6



Chemistry in Action

(a) *iprofloxacin (b) !aracetamol (c) Ibuprofen (d) 'ocopherol

Q 9. "hich of the following is not an antibiotic

(a) !enicillin (b) Sulphaguanidine (c) *hloramphenical (d) None of these

Q 10. "hich is correct about saccharin

(a) It is (b) It is +,, times sweeter than sugar

(c) It is used as sweetening agent (d) All of these

91

17 chemistry in action 87-90

Documents