Preparation of sample solution Accurately weigh and transfer 1g of sample in a clear titration vessel add 10 ml of pH 10.00 Buffer (ammonia
ammonium chloride) sonicate to dissolve add 60 ml water. Then titration with 0.01 M Copper sulphate determine the
end point potentiometrically note down the volume as V1(ml).Perform the Blank titration without sample addition
note down the volume as V2 (ml).
EDTA Content (%w/w)=(V1(ml)-V2(ml)) × N × 29.22/Weight(g)
V1 (ml)=Volume in ml of copper sulphate solution consumed in the sample.
V2 (ml)=Volume in ml of copper sulphate solution consumed in the blank titration.
W1 (g)=Weight of the sample taken in grams
RESULTS AND DISCUSSION Method development activity The most commonly used method for the determination of trace level ethylene diamine tetra acetic acid in pharmaceutical
drug substance. The objective of this work is to determine trace level EDTA [5,6]
in pharmaceutical drug substances.
Any impurity other than the active moiety has to be controlled as a part of specification. This is the one impurity we
are controlling with cost effective process. During method development 6-APA solubility was studied finally pH 10
Buffer (Ammonia ammonium chloride) chosen as a diluent to dissolve the sample. The following titration parameters
are followed estimation of EDTA content.
Optimised titration parameters Titration mode: MET U
Signal Drift: 50 mv/min
Min Wating time: 0 s
Max Waiting time: 26 s
Dosing Volume Increment: 0.02 ml
Dosing rate: Max
Stop volume: 2.5 ml
Potentiometric evalution EP Criterion: 5 mv
EP Recogmition: Greatest
Initial Measured value signal drift: off
Solubility of 6APA Based on trial and error method 6APA is not at all soluble in different solvents. Finally we have chosen pH 10
ammonia and ammonium chloride buffer. Initially for 1 g of sample 10 ml of pH 10 Ammonia ammonium chloride is
sufficient to clear the solution after addition of 10 ml of buffer stir the solution until it will clear then add 60 ml water
to proceed for the titration.
