Doping

my father said that Salbutomol has a notoriously poor level of uptake on inhaled delivery, as low as 30%, which is far lower than many other drugs. As such, 70% can be passed out in the urine at any given moment, hence his arguement that blood-tests should be used rather than urine tests to show how much is actually being absorbed in the blood as opposed to simply washed through

Either his father doesn't know what he's taking about, or he didn't properly understand what his father told him.

Inhaled salbutamol tends to end up in one of three places; the target receptors in the lungs (this is where the 30% (±10) comes into it), deposited in the mouth and swallowed, or exhaled. The exhaled portion obviously can't have any effect, it's just wasted. The portion which is on target is eventually transported via the blood stream to the kidneys and pissed out, as is the swallowed portion which is absorbed through the gut. While it's in transit in the bloodstream, it can have systemic effects which are either unwanted drug side effects or desired performance enhancing effects, depending on who's asking. Inhalation of small doses (100μg nominal per puff) is chosen for therapeutic use because it minimises side effects, and for exactly the same reason it's a pretty useless way to try to get performance enhancing effects. When I was a boy, before metered does inhalers were ubiquitous, we used to take 4mg tablets and live with the side effects. Anybody trying to get measurable performance enhancement from salbutamol will be taking 2-4 of those every day for weeks or months at a time.