Question

In your lab there is a colony of 200 gerbils all weighing about 55g. They seem to be coming down with a respiratory infection, so the veterinarian asks you to deliver 300mcg/kg/day of oxytetracycline PO to each gerbil each day for 30 days in their water. you know each gerbil drinks 4mls per day. oxytetracycline comes in 2mg/ml and you will be making it in gallon (3785mls) jugs to refil their water

A) what is the concentration of oxytetracycline in a gallon jug

B) how will you make each gallon? ____mls oxytetracycline + ______mls water

C) how many gallons will you need to treat the gerbils for 30 days?

Answer 1

Each gerbils weigh 55g or 0.055 kg

Oxytetracycline needed by each in one day :-

For 1kg, 300mcg is the limit

For 0.055 kg, 300×0.055mcg should be given in a day.

Each gebril drinks 4ml of water each day.

So (0.055×300) mcg should be dissolved in 4mls of water each day.

A)So in a gallon jug containing 3785mls of water, the concentration of oxytetracycline is [{(0.055×300)/4}×3785] mcg i.e. 15613.125mcg or 15.6 mg approx. (1mg is equals to 1000mcg)

B) oxytetracycline comes in 2mg/ml i.e. 1ml contains 2mg i.e. 2000mcg.

In 1 gallon oxytetracycline present is 15.6 mg

Therefore, amount of oxytetracycline required is 15.6/2 ml or 7.8 units. Or roughly 8 units.

So 8mls of tetracyline in 3785 mls of water will make 1gallon of oxytetracycline.

C) Each day 4mls for one gebril.Total 200 gebrils. So each day 200×4 mls solution. In 30days 200×4×30 mls i.e. 24000mls or (24000/3785) gallons or 6.34gallons.