08-31-04 10:19
No 528453
Hey All: The following is just something that I have been noodleing off and on for about a year now, it might be a stupid question, or maybe not, it might get me flamed, or it might not, in any case I just have to know, its been bothering me for to damn long.
About a year and a half ago someone gave me an old copy of Remington's Pharmaceutical Sciences(Fourteenth Edition), its a pretty neat book, lots of useful imformation and other cool stuff, and I have learned alot, however one part of it puzzles me. When you look up a drug in this book(I will use Meth.HCL as the example, since this is the Stimulants Forum) it gives you all the basic imformation,Preperation,Dose,Solubility,
I thought 100.00% purity was the most you could have of anything, or maybe it doesent mean purity, maybe it means.... ahh fuck, I dont know. What does this mean. Its not just Meth, almost all the drugs say this(sometimes upto 102.00%). Ive asked around, and no one has been able to give me an answer, one guy said it has something to do with recrystalization(but I doubt that)but, the general answer given was "I dont know". So I am going to turn this question over to the most brilliant minds I know of, Hive Bees. I really hope someone can answer my question, its just been bugging the hell out of me for about a year now.
P.S. If anybody feels like flaming me for asking a stupid question(if this is one), please feel free to do so. Just do be kind and please include the answer(or how to find it)in your flame.
Thank You
Rasputin
(Hive Addict)
08-31-04 11:08
No 528458
All I can think of is that it could be a comparison of the weight of the freebase form to the HCl form. Just a wild guess.
Without the existence of idiots geniuses would simply vaporize into thin air
(Hive Bee)
08-31-04 16:23
No 528502
I've had lots of chemical bottles labeled "assay % 98,5-101,5" for example.I think it means how many percent of net weight compromises pure substance and that way it could also be over 100% since bottle can always contain more than label says.
(Hive Addict)
08-31-04 20:13
No 528544
I think the topic of percentages is his all time favorite subject.
See this related thread Post 525008 (pink_dust_angel: "what does % mean?", Newbee Forum)
That thread deserved a nomination for "the most stubborn argument of the year" award.
Without the existence of idiots geniuses would simply vaporize into thin air
(Newbee)
09-01-04 22:06
No 528920
(Rated as: correct)
Maybe it has to do with the way the purity of said compound is determined. I remember doing quantitative GC analyses. I had to inject solutions with different concentrations to construct a calibration line (quantity/detector response relation) When using a calibration line it is possible to have a value over 100%, for instance when injecting a sample a second time. The response can be slightly higher, depending on a number of factors that detrmine the outcome of an analysis. Every result of a measurement will have a certain uncertainty which will add to the real value. In this way one can get +100% results. Just a guess...
A little poison now and then: that makes for agreeable dreams.
(Hive Bee)
09-06-04 23:25
No 529958
Chimitant has it right. Every measuring procedure has a certain imprecision, which is also knwon as the 'error bar'.
In the given case, if your equipmnet gives you a reading of '99.5% puritiy', and this device has an imprecision of '+- 1%', yould would quote '98.5%-100.5' as the result of the measurement. The correct value will be in this range.