Weighing of coated tablet powder

[Sunjay]

Dear All

If we have to weigh the sample for coated tablets after grinding them, whether the powder should be weighed with coating or
the coating should be removed from the powder?

What could be the more acceptable method?


Regards

[DR]

With.

[syx]

I think the problem is when the coating material could be pulverized finely. It tends to form slices. You may ‘peel’ the tablets before weighing and pulverizing – or transfer 20 tablets directly to a volumetric flask of such capacity, add diluent and shake by mechanical means for certain minutes to disintegrate the tablets.

[Sunjay]

Presently we are trying to use 20 tablets directly in most of the methods, but this adds up the cost as we have to use more solvents etc.


Thanks for ur reply.

Regards

[HW Mueller]

Sunjay, estimate the costs (in terms of money as well as ethical aspects) of faulty analyses and you will be doing fine with more solvent....

[yogesh#14]

Dear All

If we have to weigh the sample for coated tablets after grinding them, whether the powder should be weighed with coating or
the coating should be removed from the powder?

What could be the more acceptable method?


Regards

Dear Sunjay,

Weigh the coated tablets as whole. If you try to weigh it without coat it s difficult and could generate errors . You can dilute it according to the standard and apply the dilution factor to get the assay value.

Yogesh

[syx]

yogesh, if you weigh the coated tablets to get average weight, pulverize it and then weigh the powdered tablets without coat and use the average weight of coated tablet in percentage calculation, you will get higher result. Why? Because you substitute the portion of coat (without API) with the tablet core (contains API).

[syx]

Does anyone know about mills, blenders, or other instruments which are able to pulverize 'coating plates'?

[Alex Buske]

For IR samples "ball mills" (don't know the correct english name) are used. I have also seen bigger examples that could take 20 tablets

Alex

[syx]

I have reference about solid-handling techniques, i.e. grinding and milling. Tablets can be ground rapidly by a variety of lab mills or blenders, such as ball mill, micro mills, freezer mills, etc.
I just want to know which type is suitable to pulverize entire part of the tablets: cores and coating-shells.
Coating shells are very difficult to be grounded using manual grinding with a mortar and pestle. It always creates thin elastic pieces.