Question

Could someone help with these questions? Thank you!

Urea • 12 % W/W Petrolatum qs 120 g A 40% WN urea solution (SG = 1.09) is available to use to compound this ointment. Calculate for an additional 5 % ointment • a) To compound the above formula, how many mL of the 40% WN Urea Solution should be measured? b) How many grams of aquaphor should be weighed? (Use a 1:1 ratio of 40 % Urea Solution to Aquaphor) c) How many grams does the solution calculated for "a." weigh? d) How many grams of petroleum jelly should be weighed?

Answer 1

a) 36 mL

b) 67.68 g

c) 33 g

d) 87 g

Solution:

100 g is equivalent to 100*1.09 mL=109 mL

40 g/100 mL= 43.6 g/100 g

so for 12% w/w solution:

0.436*x=0.12*120

x=33 g (c)

33 g is equivalent to 33*1.09=36 mL (a)

Weight of petroleum gel= (120-33) g = 87 g (d)

Weight of aquaphor = {(1-0.436)*120} g = 67.68 g (b)