Hi all,
I am working on a molecule which is highly soluble in water. During the process of developing assay method (by HPLC) this molecule I facing a problem. Based on the solubility, I have selected H2O: ACN (90:10) as a diluent for my finished product assay method. Being a highly soluble molecule, it has to give 100% recovery in the assay. But it is giving only 90% in all the levels (50%, 100% and 150%).
In my formulation the excipients are microcrystalline cellulose, croscarmellose sodium and magnesium sterate. I believe these excipients are regular excipients which may not hide the active.
I have taken several trails by changing the ratio of diluent (H2O: ACN), but the results are same as above.
Please let me know, did any one face the above situation?
What are the possibility get such recoveries?
Hi Moka.
You have many factor to evaluate for this issue. By description this is a systematic issue, if you find this source you will solve the problem. I believe you know your target compound solubility, but the molecule could be interact with any component in your analysis. May be a volumetric flask (some molecule could interact with glass) or filter.
Hi Marcos,
Thanks for your reply...
The API as such giving good response with the same as glass or filter. The lower recoveries are observed in presence of placebo only.
If the placebo masking the some portion of API, how the recoveries are same for all the levels (50%, 100 % & 150%). It should be high for 50% and lower for 100% or 150% based on the active concentration.
First re-prepare the reference standard in duplicate and if you get the same results start doing recovery experiments with individual excipients and combinations as well to identify the root cause of low recovery. Also you consider using low binding glassware.
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