[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Dosing and quantitation
Diane Brown wrote:
>
> Just dilute your stock solutions (via serial dilutions, like
> in chemistry class) so your're dosing easily measured
> amounts. make the solutions so your usual dose is 1 teaspoon,
> or 5 cc, and your measurements become simple and quick and
> you don't need to bother with little tiny syringes. And by
> the way, the diabetic syringes I've prescribed for my
> patients are marked in 0.02 cc increments--but they're only
> available by prescription, as far as I know (they come with
> needles attached, after all). They do exist but aren't very
> available. Diluting your solutions is easier--and most of the
> chemicals we'd be working with should be quite stable in
> dilute solutions.
>
> Diane Brown, MD, PhD Fellow in Pediatric Rheumatology and
> Immunology St. Louis Children's Hospital
> 314-454-6124/brown_d at kids_wustl.edu
> ________________________________
How do you measure your stock solutions then? The higher the
concentration of the solution you are working with, the higher the
errors: a ±0.2mL error measuring a 10,000 mg/L solution gives a larger
dosage error than a ±0.2mL error measuring a 0.01 mg/L solution.
Serial dilution is amplifying measurement errors also. That's why
measuring out 100cc in a proper vessel is more accurate than measuring 6
Tbsp and 2 tsp.
I'm not saying that it is all terribly important to be that accurate,
just that I like to be. My personality is just that way. I set my
watches to the NIST atomic clock regularly (to keep within ±1 second), I
measure things with calipers and/or a micrometer instead of a ruler. I
can't help it ;-)
--
Jerry Baker