[becchino]

Hi. I have a problem with this API.

My pH result is 7.0!!

Any ideas?

[Arkcon]

Well, one idea I'd like start with is that there's no need to scan the entire pharmacopeia page for your question.  Maybe you think it adds depth to your question, but it looks to me like you wanted to save typing, and people who take one shortcut often take other, bad shortcuts.  Just letting you know from the start.

OK.  You want a pH of 7.5 to 8.5, and you have 7.0.  That sort of question comes up very often.  You can't adjust, because this is a qualitative test.  But the same issues apply:  Did you prepare this properly according to all the instructions?  You can type that procedure in, by hand please, so we can check.  Is your instrument calibrated properly?  How do you know that?

If you're sure, I would state, by whatever procedure you have, that this is an Out of Specification raw material.  You must not use this, until you have solved all the problems with it.  This is a raw material, for production, am I correct?

[becchino]

The instrument is calibrated daily with the pH 1 4 7 10 12 Standard. I also tried with other pH in my possession . The procedure for preparing the solution is the one indicated in the pharmacopoeia ( solution s )= dissolve 0.4 g of Sample in 50ml Water.
Yes this is a OOS.

PS You are wrong. I entered the parmacopea page primarily to show the molecular formula .

[Arkcon]

Ok.  Now I'm glad we have the exact page from the pharmacopeia, to compare to your text of the procedure.  Can you reconcile the differences for us?

This is an OOS.  Now, how have you begun to address it?  You have recalibrated your instrument recently.  Is it working correctly.  Those terms are not synonyms.  You must now prove your instrument was accurate.

How many times have you evaluated this sample?  Have you evaluated a previously good retain?  Do you get the same result for the retain as you have recorded?

[becchino]

Thanks! My procedure:

weigh 400 mg of sample. Add water and warm to 40 ° C if necessary. Dilute to 50 ml with water.

measure the pH must be between 7.5 and 8.0.


I recalibrated our pH meters. all other analyzes are comply.

the api manufacturer certifies= pH 8.0

[Arkcon]

OK, if you look at Borek:'s sig, you'll find his web pages detailing how pH meters should be used.  You are overlooking some basic and some more advanced concepts.  And they may be affecting your results.  You'll need also to talk to someone who's more of an expert on cGMP compliance, you are again, missing some basic and some more advanced concepts for handling OOS results.  I want you to study your question, re-read my suggestions, and then, finally, actually answer the questions I ask.