Bioequivalence and Bioavailability Forum 12:52 CET

Main page Policy/Terms of Use Abbreviations Latest Posts

 Log in |  Register |  Search

chandru
Junior

India,
2018-09-10 17:33

Posting: # 19255
Views: 429
 

 How to prepare QC for endogenous molecule [Bioanalytics]

We are quantifying Levothyroxine in serum by LC-MS/MS method. Since it is endogenous molecule we are going by Standard addition method.

Calibration range- 35 to 350ng/mL
Typical endogenous level- 40 to 80 ng/mL
LLOQC-35ng/mL
LQC-60ng/mL
IMQC-90ng/mL
MQC-160ng/mL
HQC-270ng/mL

Doubt:
Since we are going by standard addition method, how the quality control samples be prepared?
Assume that before QC preparation the endogenous level was determined and it is 50ng/mL.
1.LQC preparation -Endogenous(50ng/mL)+spiked (10ng/mL) and capturing the nominal concentration as 60ng/mL
or
2.LQC preparation-Endogenous(50ng/mL)+spiked (60ng/mL) and subtracting the endogenous level in QC as well(like subtracting from Calibration standard).

For standard addition method how to prepare quality control samples.

a. In other words the doubt is, while preparation of QC sample the endogenous concentration level should be considered or not.
b. If procedure 1 is correct. Other QC samples can be prepared by additive (E+spiked) but how to prepare LLOQC samples in validation.

If there are any literature regarding standard addition can you please share.

Is there any guideline requirement for LLOQC concentration?
If my LLOQ(CS01) is 35ng/mL
Then my LLOQC should be of what concentration?(eg. between 35-37 or 100-105% of LLOQ)

Regards,
Chandru
chandru
Junior

India,
2018-10-10 03:20

@ chandru
Posting: # 19422
Views: 197
 

 How to prepare QC for endogenous molecule

Can anyone suggest on this.
Activity
 Thread view
Bioequivalence and Bioavailability Forum |  Admin contact
18,881 posts in 4,026 threads, 1,271 registered users;
online 25 (1 registered, 24 guests [including 22 identified bots]).

Being ignorant is not so much a shame,
as being unwilling to learn.    Benjamin Franklin

The BIOEQUIVALENCE / BIOAVAILABILITY FORUM is hosted by
BEBAC Ing. Helmut Schütz
HTML5 RSS Feed