# Standard and sample concentration

Scenario Number 1 (Assay Test):

Standard Concentration: 0.12mg/ml
Sample Concentration: 0.15mg/ml

Scenario Number 2 (Dissolution Test):

Standard Conc 1: 0.025mg/ml
Sample Conc 1: 0.028mg/ml

Standard Conc 2: 0.02mg/ml
Sample Conc 2: 0.022mg/ml

In order to calculate the percent dissolved (disso test) and percent label claim (assay test), the standard conc should be equal to the sample concentration. With the above mentioned values, can we accept those difference we made for our standard and sample preparation? Thanks.

The answer to this questions depends on what has been demonstrated to give acceptable results in the validation studies.

I would recommend that the concentration of the standard solutions should equivalent to that expected from 100 % label claim of the product. I would also design analytical method so that the sample solution concentration (@ 100 % LC) is the same as the standard solution concentration.

What is the validated linear range?

What concentrations were used in the recovery validation experiments?

If the concentrations of the samples are within the validated linearity and recovery range, there should be no problem.

I would recommend that your laboratory establishes appropriate policies and standard operating procedures (SOPs) to cover this situation.

In the scenario presented, the assay sample concentration is 125% that of the standard concentration. My feeling is this difference is the upper limit for acceptably. I would recommend confirming results are acceptable with recovery experiments and also confirm linearity.

As for the Dissolution samples these are 112 % and 110 % of the respective standard concentrations. Again if these are within the validated linear and recovery range, there should be no problem.

Please feel free to PM me if I can be of further assistance.

Kind regards

[quote=David1]The answer to this questions depends on what has been demonstrated to give acceptable results in the validation studies.

I would recommend that the concentration of the standard solutions should equivalent to that expected from 100 % label claim of the product. I would also design analytical method so that the sample solution concentration (@ 100 % LC) is the same as the standard solution concentration.

What is the validated linear range?

What concentrations were used in the recovery validation experiments?

If the concentrations of the samples are within the validated linearity and recovery range, there should be no problem.

I would recommend that your laboratory establishes appropriate policies and standard operating procedures (SOPs) to cover this situation.

In the scenario presented, the assay sample concentration is 125% that of the standard concentration. My feeling is this difference is the upper limit for acceptably. I would recommend confirming results are acceptable with recovery experiments and also confirm linearity.

As for the Dissolution samples these are 112 % and 110 % of the respective standard concentrations. Again if these are within the validated linear and recovery range, there should be no problem.

Please feel free to PM me if I can be of further assistance.

Kind regards

[/quote]

I would recommend that your laboratory establishes appropriate policies and standard operating procedures (SOPs) to cover this situation.

In the scenario presented, the assay sample concentration is 125% that of the standard concentration. My feeling is this difference is the upper limit for acceptably. I would recommend confirming results are acceptable with recovery experiments and also confirm linearity.

As for the Dissolution samples these are 112 % and 110 % of the respective standard concentrations. Again if these are within the validated linear and recovery range, there should be no problem.

How can I perform these? thanks