Answer / falguni

Assay : We compare the area of product with working
reference Standard of that product.It also may calculate as
basis, on anhydrous basis or on dried basis.

Purity : We compare the area of our product with area of
other impurities which comes in our product.

Potency : We compare the area of product with working
reference Standard of that product, but after removing the
sum of heavy metals, sulfated ash, LOD and moisture.

Answer / bhargav

Purity:

It is calculated by area normalisation method, it can be
directly find out by chromatograms obtained from HPLC.

% Purity = (Area of desired peak / Sum of area of all
peaks) x 100

Assay:

It is calculated against standard. It may be of following
types:

1) On as is basis = (Area of sample / Area of standard) x
(conc. of standard / conc. of sample) x potency or assay of
standard
2) On anhydrous basis = (Assay on as is basis / 100 –
moisture) x 100
3) On dried basis = (Assay on as is basis / 100 – LOD) x 100

Potency:

100 – (moisture or LOD + residual solvents + heavy metals
+ sulphated ash + impurities)

Answer / a.prabhakar

Purity :
It explains how pure our analyte is in the given mixture.
It is not related to the how much our analyte is in the given mixture.
i.e.: Percentage of a our analyte without impurities in HPLC.(Known or Unknown)
Assay:
It explains how much our analyte is in the given mixture (The content of our component in the given mixture).It is not related to analyte purity.
Potency :
It is measurement of our analyte how potent it is.
i.e: Purity of our analyte without all possible impurities like chromatographic impurities (HPLC, GC-Residual solvents, moisture, TLC), heavy metals, sulphated ash...etc

Answer / obaiah kade

assay mean quantity purity mean quality

Answer / ala

in the answer above the first two definitions is true
for potency there is relation ship between potency and activity of the product as antibiotics and i am sure its related to micro lab

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