What 
              is 
          Impuri
             ty?        Impurities               in 
                        pharmaceuticals  are  the 
                        unwanted chemicals that 
                        even  in  small  amounts 
                        may influence the efficacy 
                        and    safety    of    the 
                        pharmaceutical products.
                  SOURCES OF IMPURITIES
    1. Raw Materials employed in Manufacturing
    2. Reagents used in the manufacturing Process
    3. Methods or process used in Manufacturing.
       a.  Reagents added to remove other Impurities.
       b.  Solvents (Types of Waters).
       c.  Action of Solvents & Reagents on reaction Vessels.
    4. Chemical Process used in the Manufacturing.
    5. Atmospheric Contamination during the Manufacturing Process
    6. Intermediate Products in Manufacturing Process.
    7. Defects in Manufacturing Process
   8.       Manufacturing Hazards
             a. Particulate Contamination
             b. Process Errors
             c. Cross-Contamination
             d. Microbial Contamination
             e. Packing Errors
   9.Storage Conditions
                a. Filth
                b. Chemical Stability
                c.  Reaction with container material
                d. Physical Changes
                e. Temperature effect
   10.      Decomposition of the Product during Storage
   11.       Accidental Substitution or Deliberate Adulteration with spurious or 
   useless Material.
                1.Raw Materials employed in 
                              Manufacturing
      Impurities Known to be associated with these chemicals may be carried 
      through the manufacturing Process & Contaminate the final compound.
      Eg.  1.  Rock  salt  contains  small  amounts  of  Calcium  sulphate  & 
      Magnesium Chloride.  So  the  NaCl  Prepared  from  this  source  will 
      almost certainly contain traces of Magnesium & Calcium compounds.
      2.  Copper  Sulphate  is  prepared  by  the  action  of  Sulphuric  acid  on 
      copper turnings. Cu Turnings are known to have Iron & Arsenic as 
      impurities.  These  impurities  may  be  present  in  Raw  materials,  they 
      may enter the final product. Due to this IP Prescribes Limit of Tolerance 
      for As Impurities.
                       Cu + 2 H SO                      CuSO    +  
                                 2    4                      4      
                                         2H2SO4
                             
   3.  Zinc  Sulphate  can  be  prepared  by  the  action  of 
   Sulphuric acid on Zinc Metal or Zinc Oxide. Both Zinc 
   metal & Zinc Oxide are known to have Al, Cu, Mg, 
   Mn, Ni, As, Fe as impurities, which are likely to be 
   carried to the final products.
        Zn + H2SO4                          ZnSO4  +   H2