purity of drug standard on anhydrous basis.

3 posts / 0 new
Last post
gauravbhatt
gauravbhatt's picture
purity of drug standard on anhydrous basis.

Dear Dr,
If i have one drug standard with having purity of 100.00 % by HPLC. and water content 0.4% by karl fisher.
if i want to convert the above purity on as is basis than shall i use below mentioned formula??

100-water content x given purity / 100= as is basis purity.

example:

100-0.4 x 100.00 / 100=99.60% on as is basis.

Kindly reply me ASAP.

Thnaking you...

Gaurav

sivakrishna
sivakrishna's picture
I think the result will be

I think the result will be 100% as is basis and

100 x 100 / (100-0.4)=100.4% on dried basis

gab1234
gab1234's picture
But, I didn't understand...

But, I didn't understand...
If I am discounting the water. Why the value increases? I also thought that the correct value was 99.6%
Can you explain for me?
Best Regards