Teratogenic studies of insulin glargine were undertaken in rats at doses up to 0.36 mg/kg/day. Solve by using equivalent expressions.

Question

The choices are

(a) 360 cg/lb/day

(b) 792 mcg/lb/day

(c) 360 mg/lb/day

(d) 163.6 mcg/lb/day

Answer 1

Hey Jenson,

This is at least a little more reasonable than that other question. Here it shouldn't be too complex to get the dose of 0.36 mg/kg/day in terms of mcg/ lb/ day.

1. I find it easier to use big numbers, so I'd put all mass values into mcg first.
2. 0.36 mg/kg/day * (1000mcg/mg) = 360 mcg/kg/day
3. I'd also do this for all the answers, multiplying answer c by 1,000 and answer a by 10,000 to get mcg.
4. Then you just need to go from kg to lb. A physicist (like me) would tell you that this is not a conversion factor, as kg is a measure of mass and lb is a measure of weight. However, since I assume this is all done on Earth's surface, we can use the conversion of 1 kg = 2.205 lb.
5. So multiply what you have now by the expression (1 kg/ 2.205 lb). This lets your kg cancel and leaves lb in the denominator.
6. That's it - one of the answers should match.