[vsalvatorlove]

I have never been great at understanding anything science/math related without some step-by-step instruction first! I have a question regarding how much of dewormer I will end up with, if I dissolve the paste form into 1L of water (to make dosages easier).

I have 2500mg/L after dissolving the paste.

I wish to know how much fenbendazole will be present in 1cc of this solution. (I am aiming to dose at 50mg/g.)

As I understand it, 1mL is only equal to 1cc of water. When you add the medication, this changes. Do I need to calculate the molarity of the solution? The M.Wt of fenbendazole is 299.35. Is this the number I start with or am I totally off base?

While an outright answer would be helpful, of course, I would like to get an explanation or at least a formula to follow for in the future, so that I can understand and replicate this problem with different substances. Is there any information that is needed that is missing?

[Arkcon]

I have never been great at understanding anything science/math related without some step-by-step instruction first! I have a question regarding how much of dewormer I will end up with, if I dissolve the paste into 1L of water (to make dosages easier).

I have 25g of fenbendazole paste. Each gram contains 100 mg.

I wish to dilute this paste in 1L of water, and from there would like to know how many cc of this new solution will contain 50mg of fenbendazole.

While an outright answer would be helpful, of course, I would like to get an explanation or at least a formula to follow for in the future, so that I can understand and replicate this problem with different substances. Is there any information that is needed that is missing?

We're glad to help, and we want to help you learn to help yourself, so you can start to handle these sorts of calculations.  It took me a long time to understand these sorts of problems myself, and it still takes me a while on paper to do them.  Let's get started:

You have 25g of paste, each grams has 100 mg.  How much is that?  Write that down.

You dissolve it thoroughly in 1 liter.  ( I assume this is a theoretical dilution problem, I make no guarantees on your ability to make a homogeneous solution.)  How much do you have in 1 mL?  How much is a cc in mls?  Write that down.

You have a certain amount of mg/ml.  How many is 50 mg?

If you find yourself stuck, you can change the numbers to make the calculation easier, then use real numbers once you understand how.  For example:  I have 100 grams of paste, each with 1 mg per gram active.  I suspend in 100 ml.  What do I get?  That sort of thing.

[Arkcon]

Kindly don't edit your post to change it to reflect my response.  That just makes my response look stupid.  Fortunately, I found your original in my browser history, and reinserted in my response.  Kindly now respond with what you just figured out, so people can see what you don't yet know.

[Borek]

As I understand it, 1mL is only equal to 1cc of water. When you add the medication, this changes.

Dissolve in a lesser amount of water and then fill up to 1L to avoid this kind of problems.

But in general - a lot depends on the accuracy with which you measure volumes. Yes, the final volume will be off if you add paste to 1L. By how much - no way to tell with the given information. Probably by not more than 2.5% (which is 25 mL out of 1L).

And, as Arkcon said, please do not edit answered posts, or, if you must, mark modified parts of the post as edited.

[vsalvatorlove]

Arkcon, I apologize, when I edited my post my browser was still showing 0 responses. I edited simply to clarify.

[vsalvatorlove]

When I work the problem based on 1ml being equivalent to 1cc, it is pretty simple, and I end up with 1cc having 25mg of fenbendazole. My confusion is that I have been told 1 mL is only equivalent to 1cc, if it is plain water.

[Borek]

My confusion is that I have been told 1 mL is only equivalent to 1cc, if it is plain water.

Definitions has been changing in time, I believe now they are just equivalent. Besides, the difference were never large enough to have any serious effect on this kind of calculations (I believe it was below a 0.1% range).

[vsalvatorlove]

Oh, ok. thank you