17 chemistry in action 87-90
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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,
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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
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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
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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
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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&$aSeetenin*
In%e'
Asartam
e
0
AAA
A
A
-
A
AAAA
A
AA
CHO
O
H
C
H
C
C
H
H
N
NH
O
C
H
C
H
H
C
O
CHO −−−−−−−−−
/@
2acchari
n0
(H0C)
0
C
CH
3
OH
(<:#)
C(CH0)
0
OCH0
OH
(<:A)
C(CH0)
0
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+romasartic acid +rom henylalanine
methyl ester
O
NH
SO2
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Chemistry in Action
Dulcin
6
Alitame
HC
H
N
O
C
CH
H
C
H
N
NH
O
C
H
C
H
H
C
O
CHO −−−−−−−−−−
A
AA
0A
AA
-
A
AAAA
A
AA
-
#he rst oular articial sweetener was saccharin. It was mar&eted as its water soluble
sodium or calcium salt. 2accharin is aroimately 0 times sweeter than cane sugar. It has
roved to be a lifesaver for countless diabetics and is of great value to eole who need to
control inta&e of calories.
<esides saccharin, the other commonly mar&eted articial sweeteners are described here.
Asartame is unstable at coo&ing temeratures, limiting its use as a sugar substitute to cold
foods and soft drin&s. Alitame is more stable than asartame during coo&ing. Bne otential
roblem with alitame and similar tye of high'otency sweetners is the di!culty in controlling
sweetness of food. 2ucralose is redicted to become a great commercial success.
LASSROOM ASSIGNMENT
Q 1. Aspirin is
(a) Antibiotic
(b) Antipyretic (c) Sedatie (d) !sychedelic
Q 2. "hich of the following drugs is a tran#uili$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
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C
CH0
CH0
C
S
CH0CH
0
NHCONH-
OC0H
6
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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
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