Hplc on drug analysis...

[help-me-please]

Can anyone tell me the lethal dose of caffeine and cotinine you would expect to find in urine? I've looked and looked and I cannot find the answer. Any suggestions or web links would be appreciated!

[wildwood]

lethal????

[help-me-please]

well yea...LETHAL. What volume would be classed as a lethal amount in urine upon analysis if theses metabolites were detected.

[wildwood]

Theprof will be along soon to explain more expertly.

To my mind a 'lethal' dose can be varied.
The concentration to cause death within the hour or days/weeks will be very different.

Meanwhile, I'll stay of the coffee and smokes.

[237SJ]

I`m no expert but wouldn`t the lethal dose be in the breath or more importantly, the blood? If the doses of those chemicals were registering in the urine would that not mean that they have been expelled from the body so they are not lethal anymore?

[theprof]

The reason you've looked and looked and are unable to find the answer is that the figures don't exist. There are too many variables involved including such factors as hypersensitivity, race and body mass.

Cotinine, a nicotine metabolite has a half-life of around 19 hours. However urinary excretion is dependant upon the race of the individual. For example, African Americans tend to excrete cotinine slower than white races.

Caffeine in urine presents its own problems. Less than 5% of caffeine is excreted in the urine unchanged.The half-life of caffeine is highly variable and dependent on several factors. Generally speaking, younger patients, particularly infants, as well as patients with cytochrome P450 inhibition, such as pregnant patients and patients with cirrhosis, have longer caffeine half-lives than the 4.5-hour half-life in healthy, adult, nonsmoking patients. The lethal dose is approximately 150 - 200 mg/Kg. Death is associated with a serum concentration above 80 ug/ml