How much mixture of active ingredient?

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Jean-Jacques Le Gall - 20 Jul 2004 08:10 GMT

I have a university problem I cannot solve: maybe you can help me!
We are provided by a mixture of two active ingredients:
A, title 78%
B, title 9%
ratio: 8,67

I want to know how much powder I must put in each vial, knowing that I want
2000 mg of activity of A and 200 mg of activity of B

Any idea?
Thanks
AB

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HankG - 20 Jul 2004 14:27 GMT

> I have a university problem I cannot solve: maybe you can help me!
> We are provided by a mixture of two active ingredients:
[quoted text clipped - 4 lines]
> I want to know how much powder I must put in each vial, knowing that I want
> 2000 mg of activity of A and 200 mg of activity of B

A little clarification, please. Are you saying that you are starting with
one entity, a mixture of two substances? If so, then what do 78% and 9%
refer to? Does this refer to the purity of each ingredient in the mixture?
The sum of all ingredients in a mixture must total 100%.

Your statement of ratio is confusing. What does 8,67 mean? Are you saying
that the mixture contains 8 parts of 'A" and 67 parts of 'B'? In each
'vial', we would state the ratio of the two ingredients as 10:1 (ten to
one). Based on my assumptions, I calculate that each gram of 'mixture'
contains about 80mg of each substance, a ratio of 1:1 (one to one).

So either my assumptions are incorrect, or something is missing in the
translation. Please clarify.

HankG

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Jean-Jacques Le Gall - 21 Jul 2004 08:06 GMT

Yes, we are starting with one entity (A & B already mixed, in a proportion
of 10A for 1B - theoretical proportion in terms of activity).
In our mixture, we only have A & B. The activity of A being 78%, and that
of B being 9%. The total does not make 100%, as there are impurities, etc...
A is an antibiotic.
8.67 = 78/9. It means that instead of having the 10/1 ratio requested, we
have a 8.67/1 ratio.

I want to put in my vial 2000 mg in activity of A and 200 mg of activity of
B, but i do not know how to calculate this.

If I had only A to put in the vial, I would do 2000 x 100/78=2564, and thus
fill my vial with 2564 mg of A. But I have a mixture of A + B....

Thanks
AB

> > I have a university problem I cannot solve: maybe you can help me!
> > We are provided by a mixture of two active ingredients:
[quoted text clipped - 26 lines]
> Checked by AVG anti-virus system (http://www.grisoft.com).
> Version: 6.0.722 / Virus Database: 478 - Release Date: 7/18/2004

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