Question

1. You have a formula for an antifungal drug in PLO used to treat diabetic foot ulcers as follows:

Drug                                                       4g

Alcohol                                                  to dissolve drug

Lecithin Isopropyl palmitate                 40 g

Pluronic gel, 20% w/v                           160 g

1. The drug has a solubility in alcohol of 0.5 g/mL.  How much alcohol is needed to dissolve the amount of drug specified in the formula?

2. You measure the final volume of the formula after preparation and find that it is 206 mL.  What volume is required to dispense 50 mg of the drug?

3. What is the strength of the drug in the PLO formula above in percent weight to volume?

Answer 1

1. The drug has a solubility in alcohol of 0.5 g/mL.  How much alcohol is needed to dissolve the amount of drug specified in the formula?

1 ml can solubilise 0.5g

? - 4g

=8ml of alcohol is needed to dissolve the amount of drug specified in the formula

2. You measure the final volume of the formula after preparation and find that it is 206 mL.  What volume is required to dispense 50 mg of the drug?

for 4g-206 ml

50mg - ?

=50mg*206 ml / 4000 mg

=2.575 ml volume is required to dispense 50 mg of the drug

3. What is the strength of the drug in the PLO formula above in percent weight to volume?

Drug : 4g

final volume of the formula after preparation and is 206 mL

so 4g/206ml

= 0.019 % (w/v)