So much for Bio-'equivalent'...

[Guest guest]

Check this out...from the FDA...hmmmmmm...?

This is from the FDA's Electronic Orange Book...the link will take you

directly to the levothyroxine listing...if not, just click on 'Search

by Active Ingredient', then type 'levothyroxine' into the search space.

http://www.accessdata.fda.gov/scripts/cder/ob/docs/tempai.cfm (of

particular interest is the RLD column)

Current through October 2008**

http://www.fda.gov/cder/ob/docs/preface/ecpreface.htm#Reference%20Listed%20Drug

(Quoted in its entirety below)

Reference Listed Drug (RLD)

A reference listed drug (21 CFR 314.94(a)(3)) means the listed drug

identified by FDA as the drug product upon which an applicant relies

in seeking approval of its ANDA.

FDA has identified in the Prescription Drug Product and OTC Drug

Product Lists those reference listed drugs to which the in vivo

bioequivalence (reference standard) and, in some instances, the in

vitro bioequivalence of the applicant's product is compared. By

designating a single reference listed drug as the standard to which

all generic versions must be shown to be bioequivalent, FDA hopes to

avoid possible significant variations among generic drugs and their

brand name counterpart. Such variations could result if generic drugs

were compared to different reference listed drugs. However, in some

instances when listed drugs are approved for a single drug product, a

product not designated as the reference listed drug and not shown to

be bioequivalent to the reference listed drug may be shielded from

generic competition. A firm wishing to market a generic version of a

listed drug that is not designated as the reference listed drug may

petition the Agency through the Citizen Petition procedure (see 21 CFR

10.25(a) and CFR 10.30). When the Citizen Petition is approved, the

second listed drug will be designated as an additional reference

listed drug and the petitioner may submit an Abbreviated New Drug

Application citing the designated reference listed drug. Therapeutic

Equivalence Evaluations Codes Products meeting necessary

bioequivalence requirements explains the AB, AB1, AB2, AB3 coding

system for multisource drug products listed under the same heading

with two reference listed drugs.

In addition, there are two situations in which two listed drugs that

have been shown to be bioequivalent to each other may both be

designated as reference listed drugs. The first situation occurs when

the in vivo determination of bioequivalence is self-evident and a

waiver of the in vitro methodology. The reference listed drug is

identified by the symbol " + " in the Prescription and Over-the-Counter

(OTC) Drug Product Lists. These identified reference listed drugs

represent the best judgment of the Division of Bioequivalence at this

time. The Prescription and OTC Drug Product Lists identify reference

drugs for oral dosage forms, injectables, ophthalmics, otics, and

topical products. It is recommended that a firm planning to conduct

an in vivo waiver of bioequivalence will be requested, contact the

Division of Bioequivalence, Office of Generic Drugs, to confirm the

appropriate reference listed drug.

[Guest guest]

I cannot get to that page...

..

..

>

> Posted by: " cindy.seeley " cindy.seeley@...

>

<mailto:cindy.seeley@...?Subject=%20Re%3ASo%20much%20for%20Bio-%27equivale\

nt%27%2E%2E%2E>

> cindy.seeley <cindy.seeley>

>

>

> Sun Dec 7, 2008 4:47 pm (PST)

>

> Check this out...from the FDA...hmmmmmm.

> ..?

>

>

> This is from the FDA's Electronic Orange Book...the link will take you

> directly to the levothyroxine listing...if not, just click on 'Search

> by Active Ingredient', then type 'levothyroxine' into the search space.

>

> http://www.accessdata.fda.gov/scripts/cder/ob/docs/tempai.cfm

> <http://www.accessdata.fda.gov/scripts/cder/ob/docs/tempai.cfm> (of

> particular interest is the RLD column)

[Guest guest]

Guess I'll have to send you via the 'scenic route'...go to the

following link...

http://www.fda.gov/cder/ob/default.htm

Then just click on 'Search by Active Ingredient';

then type 'levothyroxine' into the search space.

Leave 'Rx (Prescription Drug Products)' checked.

Click on submit and it will take you there...

>

> I cannot get to that page...

>

>