A bottle contains 5ml of a 2% solution. The dose is 5mg. How many doses are contained in the bottle? Show work

Question

I am in a online pharm tech class and I have received the above problem. Every formula I use that was given by my teacher doesn't seem to work. Please help and show how you receive the answer as well as an suggestions to help me with future problems like this..

Answer 1

the percentage of the 2% is called 'solution strength'. It means that each 100 ml of solution contains 2 mg of drug.

therefor:              

100 ml ----------> 2 mg

5     ml ---------->  X

X = 5 × 2 /100 = 0.1 MG

So, the amount of drug contained in the 5 ml bottle is 0.1 mg.

So, no of doses can be obtained by dividing the amount of drug by the the dose in mg. Thus,  0.1 / 5 = 0.02 doses.

So, ur bottle contains 0.02 dose(s).

and my advice to u is to get a pharmaceutical calculations text

and u should know that problem solving is a matter of practice, practice a lot and u'll be pro.

hope i helped.

Answer 2

The main equation you have to remember is:

     dose(mg) = bottle(mL)  x  concentration(mg/mL)

What's throwing you off is the 2% concentration. That's just another way of saying that for every 100mL in the bottle there are 2mg.

Here's a real-world example for you: I take testosterone injections from a 10mL vial, and my dose is 50mg. The concentration is 200mg/mL. So each dose is 0.25mL (1/4cc), and there are, therefore, 40 doses in each bottle. See? (Most of the time in the pharmacy, you'll actually see concentrations of liquids written as mg/mL, not as percentages. Percentages are more often used for creams, ointments, lotions, etc. -- especially the steroids.)