How would you prepare 10 ml of a 1000 fold concentrated stoc

How would you prepare 10 ml of a 1,000 fold concentrated stock of Tetracycline if the working concentration is 50 µg/ml.

Solution

Answer :

Working concentration: 50 µg/ml.

Stock: 1000 fold concentrated, means 50ug x 1000 = 50000 ug/mL

We need to prepare 50000 ug/mL and we need 10 mL of this

For 1mL we weight 50000 ug

For 10 mL we weight 50000 ug x 10 = 500000 ug

500000 ug=500mg

Weigh 500 mg and dissolve in 10 mL to get 1000 fold concentrated stock of tetracycline