Question

3. From the following formula, calculate the quantities required to make 5 lb o hydrophilic ointment. Methylparaben 0.25 g Propylparaben 0.15 g Sodium lauryl sul ate 10 g Propylene glycol 120 g Stearyl alcohol 250 g White petrolatum 250 g Purif ed water, ad 1000 g

Answer 1

The given question is incomplete. The complete question is as follows.

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

Explanation:

For the given quantities, the sum is 620.4 g. Now, amount of purified water (to make 1000 g of ointment)  is as follows.

             1000 g - 620.4 g

           = 379.6 g

Now, to make 5 lb we will calculate the quantities as follows.

Formula weight = 1000 g

Therefore, desired quantity is as follows.

             5 lb = 5 x 454 g

                     = 2270 g

Hence, this means the factor is  calculated as follows.

       $\frac{2270 g}{1000 g}$

            = 2.27

Now, we will calculate the quantity of each ingredient using factor 2.27 as follows.

• Methylparaben = 0.25 g x 2.27 = 0.5675 g

• Propylparaben = 0.15 g x 2.27 = 0.3405 g

• Sodium Lauryl Sulfate = 10 g x 2.27 = 22.7 g

• Propylene Glycol = 120 g x 2.27 = 272.4 g

• Stearyl Alcohol = 240 g x 2.27 = 544.8 g

• White Petrolatum = 250 g x 2.27 = 567.5 g

• Purified Water = 379.6 g x 2.27 = 861.692 g