how will you prepare the stock solution and many mls will administer to this group

Question

A group containing 5 rats in an analgesic experiment are to be administer equal volume ibuprofen analgesic at 400mg/kg. If the laboratory instructor directed you to use a 50mg/ml solution, how will you prepare the stock solution and many mls will administer to this group (1 tab ibuprofen = 200mg, weight of rats in grams (150, 175, 200, 210, 185).

Answer 1

To make the 50 mg/ml solution using tabs of 200 mg you would dissolve 1 tab (200 mg) in 4 ml:

200 mg/4ml = 50 mg/ml

Since you will be giving each rat 400 mg/kg, we can now determine the total number of mg of ibuprofen needed as follows:

weight of rat in kg x 400 mg/kg = mg ibuprofen

0.150 kg.................x 400 mg/kg = 60 mg x 1 ml/50 mg = 1.2 ml injected

0.175 kg.................x400 mg/kg = 70 mg x 1 ml/50 mg = 1.4 ml injected

0.200 kg.................x400 mg/kg = 80 mg x 1 ml/50 mg = 1.6 ml injected

0.210 kg.................x400 mg/kg = 84 mg x 1 ml/50 mg = 1.7 ml injected

0.185 kg..................x400 mg/kg = 74 mg x 1 ml/50 mg = 1.5 ml injected

So the total mg of ibuprofen need for this experiment will be 368 mg and total ml injected = 7.4 mls

Since each ibuprofen tab is 200 mg, you will need at least 2 tabs (400 mg)

So, dissolve 2 tabs in 8 mls (50 mg/ml).