This document discusses astringents, which are agents that work by precipitating proteins and forming a protective layer on surfaces to stop bleeding by constricting blood vessels. Astringents have local styptic and antiseptic actions and can stimulate wound healing in small quantities but cause irritation in high doses. They are used to treat diarrhea, arrest hemorrhaging, reduce inflammation, decrease sweating, and promote healing. Astringents work by constricting capillaries, decreasing blood supply to tissues, reducing skin pore size, and having antimicrobial effects through protein precipitation. Potash alum is provided as an example astringent, with its chemical formula, properties, method of preparation, and uses.

1. ASTRINGENT
TAUFIK MULLA
ASST. PROFESSOR
DEPT. PHARMACEUTICS
SPBC COLLEGE OF PHARMACY

2. ASTRINGENT
• Word derived from Latin word ADSTRINGERE meaning TO BIND FAST.
• These are the agent which work on principle of protein precipitation and
form a protective layer on the surface and stop bleeding by constricting
the blood vessel.
• Astringent protect from external irritation and reduce cellular
permeability.
• It having local styptic and antiseptic action.
• Apply over the wound in small quantity to stimulate growth of new
tissue but in high concentration it produce irritation or corrosive effect.
• Corrosive property useful in removal of undesired tissue.

3. USES OF ASTRINGENT
• To treat diarrhea
• To arrest hemorrhage by coagulation of blood
• Reduce inflammation of mucous membrane
• Decrease sweating
• Promote healing process
• Produce deodorant property

4. ASTRINGENT CAUSE
• Constriction of capillaries and small blood vessel in stopping of blood by
coagulation.
• Anti inflammatory action by decrease supply of blood to tissue.
• Antiperspirant action by reduce pore size of skin
• Antimicrobial action by protein precipitation mechanism

5. POTASH ALUM
• Chemical formula – KAI(SO4)2.12H2O
• Molecular weight – 474.33
• Synonym – potassium-alum , aluminum potassium sulphate.
• Properties –
• Color – large colorless crystal
• Odor – odorless
• Taste – sweet astringent taste
• Solubility – soluble in water , insoluble in alcohol

6. • Method of preparation –
It is prepared by adding a concentrated solution of potassium sulphate
to a hot solution of equimolar portion of aluminum sulphate.
K2SO4 + Al2(SO4)3 + 24H2O 2KAl(SO4)2.12H2O

7. • Uses –
• Used as powerful astringent
• It precipitate protein
• Dil. Solution used as mouth wash and gargle.
• Used as antiseptic
• Used as pharmaceutical aid
• Used as bladder irritant
• 2% solution used for skin application to reduce excessive perspiration