Hone

Lessons · Pharmacy · making a batch from a recipe

Making a batch from a recipe

A batch is a per-unit recipe multiplied by the number of units, weighed out in order and written down as it goes.

Hone is a place to practise a career, one idea a day. This is one of its lessons, written out in full and free to read without an account.

What it is for

The compounding log is the only record that the batch was what the label says. Six months later, a question about one capsule is answered from that sheet or it is not answered at all.

How to think about it

Work out the amount of each ingredient for the whole batch before anything is weighed: the per-unit amount times the number of units, converted into the unit the balance reads. Then weigh, then record, then mix, in that order, one ingredient at a time.

Worked example

Recipe for 100 capsules; you need 250
Factor = 250 / 100 = 2.5, or work straight from the per-capsule amounts.
Drug: 20 mg per capsule x 250 = 5,000 mg = 5 g
Per unit times the number of units, then onto the balance's unit.
Filler: 180 mg per capsule x 250 = 45,000 mg = 45 g
The same for every ingredient in the recipe.
Total: 5 g + 45 g = 50 g
Which is 250 x 200 mg, and that is the check.

Your turn

A recipe makes 60 capsules and you need 180. Write the factor.

180 / 60 = 

The trap

Weighing the per-capsule amount instead of the batch amount. Twenty milligrams is what goes in one capsule; the balance needs the grams for all of them.

Practise making a batch from a recipe on HoneA question on it now, a coding challenge where there is one, and it is remembered for review. Free, no email needed.