By Paul on Tuesday, May 11, 2004 - 01:43 pm:
When you want to validate a HPLC method for the assay of some tablets, you should proove linearity.
How do you do this? Do you actually make tablets of 70 - 80 - 90 - 100 - 110 - 120 - 130 % content of the theoretical value? Or do you use tablet powders made at laboscale? What with tablets that requires granulation steps?
I'm interested in the answers
Regards
Paul
By Anonymous on Wednesday, May 12, 2004 - 05:16 am:
The linearity you just perform with the standard solution, not with the tablets. This way you'll check the linearity of the main substance. The other tests you perform with the tablets.
By syx_gf on Wednesday, May 12, 2004 - 05:32 pm:
Linearity just with standard soln. You need simulation tablets (powder) of 70 - 130% content of active ingredient for accuracy and precission test. Just make the powder as same as your formula's content, no need to make tablets.
By Tim on Thursday, May 13, 2004 - 06:23 am:
To add to syx0gf message: It is possible that your manufacturing people will have made placebo tablets which have the same composition as the final product but without the active. Grind these up and blend with the relevant amount of active for the accuracy/recovery studies. You MUST do this by changing the amount of active and keeping the amount of placebo constant, not just making up a mix of both and weighing different amounts.
As mentioned in original reply, actual linearity of the active response is just done on standards, but you still have to check interaction/interference from inactive components too.
By syx_gf on Thursday, May 13, 2004 - 05:53 pm:
"You MUST do this by changing the amount of active and keeping the amount of placebo constant, not just making up a mix of both and weighing different amounts."
I think we should keep the same average weight of each tablet. If we reduced amount of active we must increase amount of placebo and vise versa. Therefore, we weigh the same amount of accuracy powder.