Pharmacy calculations - working with powder volume

Try to post your problem here, there is a chance, someone clever will help you.
Forum rules
Dear convert-me.com forum visitors,

Our forum has been available for many years. In September 2014 we decided to switch it to read-only mode. Month after month we saw less posts with questions and answers from real people and more spam posts. We were spending more and more resources cleaning the spam until there were less them 1 legitimate message per 100 spam posts. Then we decided it's time to stop.

All the posts in the forum will be available and searchable. We understand there are a lot of useful information and we aren't going to remove anything. As for the new questions, you can always ask them on convert-me.com FaceBook page

Thank you for being with us and sorry for any inconveniences this could caused.

Pharmacy calculations - working with powder volume

Postby TNIrisman » Mon May 14, 2007 10:18 am

Can someone please help me - I am a pharmacy student and I can't figure this stuff out.

What is a powder volume?

Example: You need to make an injectable solution with a final concentration of 375 mg/mL. On hand you have a vial that contains 1.5 grams with the instructions to add 3.3 mL. What is the powder volume?

Any help possible - I would be so greatful.

Tina
TNIrisman
 
Posts: 1
Joined: Mon May 14, 2007 10:04 am

help with powder volume

Postby Guest » Mon Jul 16, 2007 4:08 am

What you need to do is convert your 1.5 G into milligrams first. Then you solve for x. You allready know your final concentration is to be 375 mg in 1 mL. Find out how many mL will be in your 1500 mg of drug. The answer is 4 mL. Your instructions are to add 3.3 mL of diluent. Subtract your total which is 4, from your 3.3 mL. the answer will be a powder volume of 0.7 mL. That is the displacement of the powder in the vial. Your vial will explode if you do not include a powder volume.
Guest
 

Re: Pharmacy calculations - working with powder volume

Postby CaitlanK » Thu Jul 28, 2011 4:05 am

The directions for mixing a 250mg/5ml liquid antibiotic state when 80ml of water are added to the contents of the bottle the resulting volume is 150ml. determine concentration of the drug in mg/5ml if only 40ml of water were added?

i already determined the total mg of the drug in the bottle which is 7500mg, i then determined the powder volume of the drug in the bottle which was 70ml. then i had to figure out the volume of the new product, which i solved by:
New Product(NP)=D+PV
NP= 110 ml
At the end of this problem i have to write out the new concentration as total mg drug in bottle/volume of new product
which would look like this 7500mg/110ml, in my textbook they converted that into 6.82mg/ml then converted that to 341mg/5ml.
My question is how did they get 7500mg/110ml to convert to 341mg/5ml.

Help im not understanding the conversion on the last question!
CaitlanK
 


More info

  • List of all units you can convert online
  • Metric conversion
  • Convert grams to cups
  • Grams to milliliters
  • Imperial vs US Customary
  • History of measurement
  • Return to Other math problems



    Our Privacy Policy       Cooking Measures Converter       Metric conversions