Posted by yxibow on April 28, 2009, at 18:36:48
In reply to Re: Anyone having trouble with new generic Lamictal?, posted by zana on April 28, 2009, at 9:59:42
> I hope you get the Teva soon. I got two different generics of Provigil when I was on an insurance plan that would not approve the brand name and they were definitely not Provigil. Someone may correct me but it is my understanding that generics only have to contain 70% of the same ingredients that are contained in the brand name they are copying.
Its a bit more complex than that -- the medication has to be proven to be as effective as the original. That is what is referred to in the Orange Book (FDA) generally as "AB" or similar A acronyms.B compounds may differ and are a different classification under the Orange Book. The generics that are out there in large circulation in general never fall into the B category.
There may be different binding ingredients (e.g. stearates, gelatins, colors, etc.) in one generic or the other, or between thet original.
The general gist is that it has to be between 80% and 125% over the AUC (area under the curve) which is a complex mathematical formula representing bioavailability....
...Wikipediia: "Bioavailability is a measurement of the extent of a therapeutically active drug that reaches the blood and is available at the site of action").
But then it gets more complex, bioequivalence, which is defined to be 90% of an even more complex statistician's delight of a "confidence interval" which separates a sample from the population at large. At that point the theoretical science goes over my head.
As noted in the previous article though, many organic situations affect this as well, including food.Thus while it is possible for there to be a lower amount in the plasma, it is entirely possible also for a generic to exceed the original.
-- Jay
poster:yxibow
thread:893156
URL: http://www.dr-bob.org/babble/20090426/msgs/893333.html