Question

From the following formula, calculate the quantities required for each of the following ingredients to make 5 lb. (avoir) of hydrophilic ointment. All values to be in g, do not include units in your submitted answer; use no more than 3 decimal places. Convert using 1 lb = 454 g. Note: all values done by mass, including the water, so this is not a q.s situation (volume is irrelevant).

• Methylparaben                      0.25 g

• Propylparaben                       0.15 g

• Sodium Lauryl Sulfate          10 g

• Propylene Glycol                   120 g

• Stearyl Alcohol                     240 g

• White Petrolatum                  250 g

• Purified Water, to make        1000 g

Answer 1

Answer -

• Methylparaben                      0.567

• Propylparaben                       0.340

• Sodium Lauryl Sulfate 22.70

• Propylene Glycol 272.4

• Stearyl Alcohol 544.8

• White Petrolatum 567.5

• Purified Water, to make 861.692

Explanation -

1lb = 454 g

5 lb = 454 * 5 = 2270g

Concentration is given for 1000 g.

Methylparaben = 0.25*2270/1000

= 0.567 g

Propylparaben = 0.15* 2270/1000

= 0.340 g

Sodium Lauryl Sulfate = 10*2270/1000

= 22.7 g

Propylene Glycol = 120 * 2270/1000

= 272.4 g

Stearyl Alcohol = 240 * 2270/1000

= 544.8 g

White Petrolatum = 250 * 2270/1000

= 567.5 g

Water

Total quantityi given = 1000g

Total amount of all the contents = .620.4

Amount of water added to make 1000g = 379.6 g

Amount of water added to make 2270 g =379.6 * 2270/1000

= 861.692 g