Chemicals in medicine satish

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Chemistry in Everyday Life

XII – ChemistryInEveryDayLife – ChemicalsInMedicine 1

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Cleansing stuffs like soaps and detergent come in our mind

when we start thinking over cleanliness.

Sickness and diseases remind us medicines.

Even what we eat are made up of different biomolecules

In short we can realize that we come across chemical

compounds every moment of our life.


Drugs

Chemical substances of lower

molecular mass (about 100-500 u)

Interact with macromolecular target

and produce a biological

response

Are called medicine if biological

response, produce by the interaction

with macromolecular targets, turns

out to be therapeutic and useful


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Medicines

Used in diagnosis,

prevention and curing

treatment of diseases

Can prove to be poisonous,

if it is consumed in higher

doses than those

recommended

Or chemicals used for

therapeutic effect is said to

be chemotherapy


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Criteria of Classification of Drugs

Drugs can be classified on the basis of mainly following

criteria

Pharmacological effect

Drug action

Chemical structure

Molecular targets



Pharmacological Effect

Drugs which are classified on the basis of pharmacological

effect is very useful for doctors.

This is because these provide whole range of drugs available for

the treatment of a particular type of problem.

Example:

Analgesics have pain killing effect

Antiseptic is used to kill or arrest the growth of microorganism.



Drug Action

Drugs can also be classified on the basis of the action these

on a particular biochemical process.

Example:

Histamine which causes inflammation in the body, can inhibit

the action of the compound.



Chemical Structure

Drugs may have same kind of chemical structures

Due to identical structures, they share similar

pharmacological activity.

Example:

All Sulphonamides have common structural feature as given

below


Sulphonamides

Plz recreate this

picture


Molecular Targets

Target molecules with which drugs usually interact are

actually biomolecules.

These biomolecules could be carbohydrate, protein, lipids

and nucleic acids.

Drugs having some common structural features may have

the same mechanism of action on targets.



Molecular Target : Biomolecules

XII – ChemistryInEveryDayLife – ChemicalsInMedicine

Proteins

Enzymes

Receptors

Career


Function of Protiens

Proteins can perform as biological catalysts in body to speed

up the metabolic processes.

These biological catalysts called enzyme

Proteins called receptors are crucial to communication

system in the body.

Carrier proteins transmit polar molecules across the cell

membrane of the organisms.

Nucleic acids such as DNA and RNA have coded genetic

information for the living cell.



Drug-Target Interaction

Majority of drugs act on receptors present in or on the cell.

Receptors, usually a protein, is a macromolecular component of a cell with which a drug interacts to produce a response.

Enzymes are treated as target.

Drug-target interaction can be understood by taking example of enzymes and receptors.



Catalytic Action of Enzymes

There are two major functions usually performed by

enzymes in their catalytic activity.

Holding of substrate to facilitates chemical reactions

Providing functional groups to accomplish reaction


Plz draw this

picture

Use green colour

in place of gray.

Red instead of

green.


Catalytic Action of Enzymes

Enzyme holds substrate

through active site in a fixed

position, so that it can be

attacked by the reagent with a

greater ease.

In the second step, enzyme

provides functional groups that

will attack the substrate and

carry out chemical reaction to

yield a product.



Drug-Enzyeme Interaction

Drugs can inhibit the activities of enzymes, is called

enzyme inhibitors.

It can block the active site of enzymes or can inhibit the

catalytic activity of enzyme.

Inhibition of enzyme take place in two different ways

By preferential attachment of drugs on the active site.

By binding of drugs with allosteric site of enzymes.



By preferential attachment of drugs on the active site:

Drugs may compete with the natural substrate for their

binding to the active site of enzyme.

Such drugs are called competitive inhibitors.


Plz draw this

picture

Use green colour

for enzyme, red

colour for drug

and orange

colour for

substrate.



By binding of drugs with allosteric site of enzymes:

Some drugs tend to bind with allosteric site other than

enzyme’s active site.

Such type of binding changes the shape of the active site in

such a way that it becomes unrecognizable for the substrate


Plz

Use green colour

for enzyme, red


Receptors as Targets

Receptors are proteins that play a major role in body’s

communication process.

Receptor proteins, are embedded in the cell, have active

site.

These active sites project out of the surface of the cell

membrane


Plz


Receptor as Targets

Animation



Drugs and Receptors

Drugs are called antagonists, if they are attached to the

receptor site to inhibit its natural functioning.

Antagonists are useful when blocking of message

(propagated by the chemical messenger) is required

Drugs that mimic the natural messenger by switching on

the receptor are called agonists.

Agonists are useful when there is lack of natural chemical

messenger.



Antacids

The chemical substances which neutralize

the excess acid present in stomach as

gastric juices and give relief from this

problems

Example:

Metal hydroxides such as

Mg(OH)2 and Al(OH)3

NaHCO3

Antacids only control the symptoms not the

root cause of secretion of excessive acids in

stomach.


Plz

And labeled it

with


Antihistamines

Histamine is responsible for the nasal

congestion associated with common

cold and allergic response to pollen.

Antihistamines destroys histamine

produced in the body by allergens,

used to treat skin rashes,

conjunctivitis.

Antihistamines prevent allergic

reactions like hazy fever, mild asthma,

nasal discharge, etc.

Example: Brompheniramine


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Brompheniramine


Tranquilizers

Drugs which act on the central

nervous system and help in

reducing anxiety.

Used for the treatment of mental

diseases and help to reduce

anxiety, restlessness and

excitement.

Are also known as

psychotherapeutic drugs.

Examples: Luminal, seconal,

equanil, etc.

These are mainly the derivatives

of barbituric acid.


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Some Important Tranquilizers


Equanil Veronal

Valium Serotonin

given


Analgesics

Used to reduce or abolish

pain without causing

impairment of consciousness,

mental confusion, some

other disturbances of nervous

system.

Are of two types

Non-Narcotic

Narcotic


Plz


Non-Narcotic Analgesics

Aspirin and paracetamol belong to

the class of non-narcotic or non-

addictive analgesics.

Aspirin an important analgesic

inhibits the synthesis of

prostaglandins which is responsible

for stimulation of inflammation in

the tissue.

Non-narcotic drugs have also

antipyretic and preventing platelet

coagulation effect.


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Aspirin


Narcotic Analgesics

Mainly used for the relief of

postoperative pain, cardiac pain,

pains of terminal cancer and in

child birth

On administrating of morphine

(an analgesics) and many of its

homologues in medicinal doses,

they relieve pain and produce

sleep.

In poisonous doses, these produce

stupor, coma, convulsions and

ultimately death.


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Some Narcotic Analgesics

Morphine narcotics are sometimes referred to as opiates as

they are synthesized from the opium poppy.


Morphine Heroin Codeine

given


Antimicrobials

Microorganism such as bacteria,

virus and other pathogens are

responsible for repercussions of

diseases in human beings and

animals.

An antimicrobial helps us to

destroy or prevent development

or inhibit the pathogenic action

of microbes or other parasites.

Example:

Antibiotics, antiseptics and

disinfectants.


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Antibiotics

Antibiotics being less toxic for humans and animals, are

used as drugs to treat infections.

Initially antibiotics were defined as chemical substances

produced by microorganisms that inhibit the growth or even

destroy microorganisms.

Now antibiotics refers to a substance produced wholly or to

a certain extent by chemical synthesis which inhibit the

growth or destroys the microorganism.



Development of Antibiotics

Paul Ehrlich, a German

bacteriologist, investigated a

medicine arsphenamine (arsenic

based structure) known as

salvarsan for the treatment of

syphilis

Although salvarsan is toxic to

human beings.


Salvarsan

given



While working on azodyes, Ehrlich noted that there is

similarity in structures of salvarsan and azodyes.

He also noted that tissue is getting coloured by azo dyes

selectively.

Ehrlich started looking for the compounds which resemble

in structure to azodyes and selectively bind to bacteria.


Salvarsan Azodyes

given



In 1932, Paul Ehrlich

synthesised the first effective

antibacterial agent, prontosil.

In the body, prontosil is

converted to a compound

called sulphanilamide, which

is the real active compound.

This triggers the synthesis of

a large range of sulphonamide

analogues.


Prontosil

Sulphanilamide

Sulphapyridine

given


Peniciline : First Ever Antibiotics

Discovery of penicillin brought

a revolution in the field of

antibacterial therapy.

In 1929, Alexander Fleming

identified antibacterial

properties of a Penicillium

fungus.

Isolation and purification of

active compound from

Penicillium fungus to

accumulate sufficient material

for clinical trials took thirteen

years.


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given


Tyepes of Antibiotics


Antibiotics

Cidal Effect Bactericidal

Static Effect Bacteriostatic


Spectrum of Action

The complete range microorganisms that are affected by a

certain antibiotic is expressed as its spectrum of action.

Broad spectrum antibiotics can kill or inhibit a wide range

of Gram-positive and Gram-negative bacteria.

Ampicillin and Amoxycillin have broad spectrum.

Narrow spectrum antibiotics are effective mainly against

either Gram-positive or Gram-negative bacteria.

Peniclline G has narrow spectrum.

Limited spectrum antibiotics are effective against a single

microorganism or disease.



Antiseptics

Chemicals which prevent the

growth or kill the microorganisms

but do not harm the living tissues

Can be applied to the wounds,

cuts and infected skin surfaces,

etc.

Also used in deodorants, face

powders and mouth washes and

mouth freshners to reduce odours

caused by bacterial decomposition

on the body or in the mouth


Plz

And labeled it

with

with


Antiseptics

Bithional is added to soaps for

antiseptic properties.

Dettol is a mixture of

chloroxylenol and terpeneol in a

suitable solvent.


Bithional

Chloroxylenol Terpeneol

given


Disinfectants

Used to kill microorganisms and are harmful to the living tissues

Used for sterilization of instruments, floors, toilets, etc.

For example,1% solution of phenol and chlorine in the concentration of 0.2 to 0.4 ppm in aqueous solution

By changing the concentration, same substance may act as disinfectant or as an antiseptic

For example, 0.2% aqueous solution of phenol acts as antiseptic while 1% solution of phenol is a disinfectant.


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Antifertility Drugs

Drugs used to control pregnancy are called

antifertility drugs.

They contain steroids for birth control.

Examples: Progestrone and Estrogen derivatives


Norethindrone

(A synthetic progesterone derivative)Ethynylestradiol

given

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