Question { Reddy Labs, 5535 }

What is use of LOD and LOQ in validtion and give range and in calculation why we use 3.3* LOD here why we use 3.3

Answer

LOD is Limit of detection. We can dedect the peak but cant quantify
LOQ Limit od quaantification. We quantify also this is known as reporting thereshold.
During the RS analysis Below LOQ level we cant included in the total impurities calculation.
LOD and LOQ Determination three methods
1.S/N Ratio method
3 or 2 ratio for LOD
NLT 10 ratio for LOQ

2. Slope Method
Plot the linearity for active and impurities through serial dilution at lower level
Formula for LOD
3.3*Slope/Std.dev
Formula for LOQ
10*Slope/Std.Dev
3. Visualization method
It will be using for only identification and TLC Method

Question { 1801 }

Dear sir, This is R.Kadambavadani working in a pharma industry. while doing RS analysis of ibuprofen API, unknown peak eluting some times in the 0.6 Min RT. Kindly send me what is the exact reason behind that. also am using ACN the mobile phase.

Answer

Please mention what is your diluent?
Whether used new HPLC vial or old?
The peak eluted for void volume please ensure what r the chemical used in this test method