Conversion from mw or MU to mg/ml help - (May/01/2014 )

Hello,

 

I'm confused...  I need 50 mg/ml of this hygromycin solution but I only have these details below and I'm not sure how to work it out.  Can someone help me?  Thanks

 

Product Specification Alternative Name: O-6-Amino-6-deoxy-L-glycero-D-galacto-heptopyranosylidene-(1-2-3)-O-β-D-talopyranosyl(1-5)-2-deoxy-N3-methyl-D-streptamine   Formula: C20H37N3O13   MW: 527.5   Source: Isolated from Streptomyces hygroscopicus.   CAS: 31282-04-9   MI: 14: 4852   RTECS: WK2130000   Quantity: 1MU (1 million units); potency ≥385 U/mg solution.   Concentration:  ≥450’000U/ml   Purity: ≥80% (HPLC)

 

Did this come as a solution or is it still in powder form?

Hi, it's in a liquid form. 

Did you get this from the product datasheet?  If so - which company is the supplier, they would normally tell you the concentration somewhere (often in U/ml rather than mg/ml though)

 

It has a rough value for concentration (>450,000 U/ml) and an amount given 1,000,000 units - so you should be able to work out volume.  You also have a potency which is 385 U/mg solution.  Assuming this is dissolved in water you can approximate that water has a mass of 1 g/ml (other solvents will be different), so you may be able to work out, given the molecular mass the amount in mg/ml.

Yes that's the product data sheet. It's the only information on there. I guess I'm really stupid but I can't work out mg/ml from this information.  It is dissolved in water.

 

What's for formula for this?  I'm used to converting mw or mg/ml into a working solution of ug/ml but I can't seem to work it out from this.

 

What does "U" mean as a unit?

 

This is the supplier website http://www.enzolifesciences.com/ALX-380-059/hygromycin-b-liquid/

Unit is as for enzymes: amount that has mode of action in defined time. 

 

C=n/v and rearrangements of that would be what you would use to get volume

Ok, like I said, I really can't work this out.  If someone gave me 100 ul of this solution and tells me that it is MW: 527.5, in it's original unknown volume it was Quantity: 1MU (1 million units) with a potency ≥385 U/mg solution and a Concentration:  ≥450’000U/ml, how do I know how much to add to 100 ml of media to get a final concentration of 30 mg/ml?

 

If you or someone else are able to determine the answer using the information can you please tell me the answer and show me the working so that I will know how to do it in the future?

1 mg of water is equivalent to 1 ul (1 kg = 1 litre, 1 g= 1 ml...).  Molecular mass is in g/mol.  mass = number of moles x molar mass

 

Now you have 385 U/mg and concentration of 450,000 U/ml

450000/385 = 1168.8 mg/ml -  but this is a concentration that I doubt, as far as I know hygromycin will only solublize to about 50 mg/ml (Merck index says "freely soluble in water" which isn't particularly helpful), most stock solutions are sold at 50 mg/ml.  Note that for a working concentration you want 50-200 ug/ml!

I interpreted his numbers as 385  units per milligram of solution, not per milligram of hygromycin. So it would be roughly 385 units per microliter. This tells you nothing without knowing units per milligram, which I think cannot be determined from the data given.

Ok thanks for your help.

 

I meant I need it to be 30 ug/ml final concentration when I use it, not 30 mg/ml, sorry for the typo.

 

I know this solution is not 50 mg/ml because this concentration can also be purchased from the same supplier but it's more expensive to buy it like this.

 

Previous suppliers that I have used have stated on the bottle that the concentration is 400 mg/ml, so maybe 1168 mg/ml is possible in this case.  The reason I was questioning this in the first place is because I have been using it as if it is 400 mg/ml like the other supplier, but I am getting fewer transformants than usual so I was wondering whether this supplier has a higher concentration.