impurities and stability studies in advanced pharmaceutical analysis. Definition of impurity, classification of impurity.

1. IMPURITY AND
STABILITY STUDIES
Submitted by,
Jikhila Machado
1st year M. Pharm
Department of pharmaceutical analysis

2. IMPURITY
Defined as any substance co-existing with the original drug, such as
starting material or intermediates or that is formed due to any side reactions .
→ Impurity means presence of unwanted foreign particle other than active
drugs which may be or may not be toxic and is found in pharmaceutical
substance.

3. CLASSIFICATION
Categories :-
i) Organic Impurity (Process and drug related )
ii) Inorganic Impuri
iii) Residual solvents
=> Organic Impurities
Can arise during the manufacturing process and/or storage of the new
drug substances.

4. -They can be identified or unidentified, volatile or non-volatile.
- can be divided into two types :
a) Degradation related impurities (DRI)
-In finished products
•API degradation
•API excipients interactions
•API residue interactions
•API container interactions

5. b) Process related Impurities (PRI)
-During the process
•Excipients interactions
•Starting material
• Biproducts
•Intermediates
•Reagents, ligands, catalyst.

6. =>Inorganic Impurities
-This can result from manufacturing process → normally
known and identified
- It include,
•Reagents , catalyst, ligands
•Heavy metals or other residual metals –cadmium ,
Arsenic, Cu
•Inorganic salts such as Copper sulphate
• other materials such as charcoal, filter aids.

7. =>Residual Solvents
- Solvents are organic or inorganic liquids used as vehicles
for the preparation of solutions, or suspensions in the synthesis of
a new drug substances.
- Residual solvents in pharmaceuticals are defined as organic
volatile chemicals that Or used in the manufacturing of drug
substances.
• Organic solvents: - CHCl3, CCl4, Ethanol, Methanol etc.
• Aqueous solvents :- Distilled water, Demineralised water,
Hard water, soft water .

8. REFERENCES
• Guidance for Industry Q3A –Impurities in New drug substances
by, U. S. Department of health and human services, FDA, CDER,
CBER, ICH –Revision 2,page no:1-6

9. THANK YOU