Sulphonamides presentation of Pharmaceutical Chemistry

Sulphonamides presentation of Pharmaceutical Chemistry

1. SULPHONAMIDES
PREPARED BY: MS. L.K.RAUT
ASSISTANT PROFESSOR
(PHARMACEUTICAL CHEMISTRY)
PES MODERN COLLEGE OF PHARMACY (FOR LADIES) MOSHI, PUNE.

2. LEARNING OUTCOME
Definition of Sulphonamides.
Classification.
Structure Activity Relationship (SAR) and their effect.
Chemical Structure of Different Sulphonamide Drugs.
Their Physical Properties.
Uses.
Pharmaceutical preparations.
Brand Names.
Storage and Stability.

3. SAR
Sulphonamides are the derivatives of Sulphanilamide having antibacterial activity.
Chemically it is p-amino benzene sulphonamide.
H2N

The p-amino group is essential for activity. Due to this reason, most of the sulphonamides have
free amino group or replaced by such functional moiety which can be easily converted to free
amino group.
They are effective against gram negative and gram positive cocci, certain gram negative bacilli
and protozoa.
They are white crystalline powders and insoluble in water. They are acidic in nature.
Their sodium salts are soluble in water.
SO2NH2
Sulphanilamide

4. CLASSIFICATION
1. On the basis of duration of action, the sulphonamides are classified as:
A] Short acting sulphonamide.
i} Poorly absorbed and locally acting.
e.g. Sulphaguanidine,Succinyl sulphathiazole
ii} Absorbed and excreted rapidly.
e.g. Sulphacetamide
B] Medium acting sulphonamide.
e.g. Sulphamethoxazole, Sulphadiazine
C] Long acting sulphonamide.
e.g. Sulphadimethoxazole, Sulphamethoxypyridazine
D] Ultra-Long acting sulphonamide.
e.g. Sulphamethoxine, Sulphamethoxypyrazine

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2. Classification depending upon their therapeutic uses:
A} Sulphonamides are used for systemic infections:
i) Urinary Tract Infections
e.g. Sulphamethoxazole, Sulphacetamide
ii) Respiratory Tract Infections
e.g. Cotrimoxazole, Sulphadiazine
iii) Meningeal infections
e.g. Sulphadiazine

6. CONTINUE…
B} Sulphonamides used for local infections:
i) Used for intestinal infections
e.g. Sulphaguanidine, phthalyl sulphathiazole
ii) Used for ophthalmic infections
e.g. Sulphacetamide
iii) Used in burns therapy
e.g. Mafenide, Silver sulphadiazine

7. MECHANISM OF ACTION OF SULPHONAMIDES
Sulphonamides are bacteriostatic in action and act by substrate competition.
Some microbes require p-amino benzoic acid (PABA) for folic acid synthesis.


Folic acid is essential for the growth of microorganism.
Sulphonamides are structurally similar to PABA, so microbes are not able to differentiate it and
consume sulphonamide.
As a result, folic acid is not synthesized and growth inhibited.
Presence of an excess of PABA antagonizes the antibacterial action of sulphonamide.

H2N COOH

8. CHEMISTRY & NOMENCLATURE OF SULPHA DRUGS
The general term “Sulpha” drugs or “Sulphonamides” has been used for antimicrobial
(antibacterial) agents. It is restricted to N-substituted derivatives of the parent substance,
Sulphanilamide (p-amino benzene sulphonamide), in which one hydrogen atom of sulphamoyl
group ( SO2NH2) is replaced by various substituents.
H2N SO2NH
R
Sulphamoyl
Sulphonamide

9. ADVERSE EFFECT
Sulpha drugs are excreted through urine as such to some extent. These are not very soluble in
acidic urine, so they may crystallize in the renal tubules, causing renal complications i.e. crystal
urea. So intake of large amount of water is beneficial.
Sulpha drugs may also produce nausea, vomiting, headache and allergic reactions.

10. 1. SULPHADIAZINE
Chemical Name:- 2-sulphanilamido pyrimidine
Physical properties:-
It occurs as white or slightly yellowish, odourless crystalline powder. It is sparingly soluble in water,
alcohol and acetone. It is freely soluble in dilute mineral acids and alkali hydroxide solution.

Stability & Storage:
It slowly darkens on exposure to light. Hence it should be protected from sunlight.

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Uses:-
1.It has an antibacterial activity, hence it is used in the treatment of meningitis (penetrate the
blood brain barrier) , Urinary tract infections and Toxoplasmosis (in combination with
pyrimethamine).
2.Its silver salt i.e. silver sulphadiazine is used topically in the treatment of burn therapy.
Pharmaceutical Preparations:
i) Sulphadiazine tablets.
ii) Sulphadiazine injection.
Common Brand Names:
Sterazine, Trimozin, Cotrizine

12. 2. SULPHAGUANIDINE

Chemical Name: p-amino benzene sulphamoyl guanidine
Physical Properties:
It occurs as white crystalline powder, which is odourless. It is soluble in water; sparingly soluble
in alcohol or acetone, soluble in dilute mineral and insoluble in alkali hydroxide solution.
Stability & Storage:
They are affected by heat & light. Also affected by presence of air & moisture. Hence they are
stored in tightly closed, light resistant containers.
Guanidine

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Uses:
It is used as antibacterial agent. And is poorly absorbed through gastro intestinal tract. Hence it is
used in the treatment of local intestinal infections like bacillary dysentery.
Pharmaceutical Preparations:
Sulphaguanidine Tablets.
Common Brand Names:
Sulphaguine, Enterogel 30, Bioguanil

14. SULPHACETAMIDE
Acetamide
Chemical Name: P-Amino benzene sulphonacetamide
OR
N¹-acetyl p-amino benzene sulphonamide

15. CONTINUE….
Physical Properties:
It is white crystalline powder, odourless; It is slightly soluble in water and ether; soluble in
alcohol; very soluble in chloroform and hot water; freely soluble in dilute mineral acids and alkali
hydroxide solution.
Stability & Storage:
It is light sensitive hence stored in well closed, light resistant container, and protected from light.
Uses:
1.It is an antibacterial agent.
2.It is used locally to treat eye infections.
3.Systemically it is used to treat UTI.

16. CONTINUE….
Pharmaceutical Preparations:
1.Sulphacetamide eye drops
2.Sulphacetamide eye ointment
Common Brand Names:
Albucid, Locula, Andremide, Phenosulf