Latex

The use of gloves and enema tips made from wet natural latex rubber, and the subsequent appearance of articles in the medical literature on the topic of latex allergies, have caused concern about the possibility of allergic reactions arising from latex leached into liquid drugs from natural latex rubber stoppers of their vials and bottles.

Natural latex rubber stoppers have been preferred for use by the pharmaceutical industry because coring from IV spike or needle insertion is less likely to occur. The rubber stoppers used to close the vials and bottles of Omnipaque, Omniscan and Visipaque, as well as the rubber plunger of the Omnipaque Prefilled Syringe, do indeed contain various percentages of highly purified dry natural latex rubber.

In February 1997, two letters from Yana Ruth Mille of the Office of Pharmaceutical Science of the federal Food and Drug Administration (FDA) on the issue of latex in vial stoppers covered the following key points:

1. Vial stoppers are molded from dry natural latex rubber.
2. All tests conducted on dry molded latex rubber fail to detect the latex protein, the presumed cause of the allergic reaction to latex.
3. As of the writing of the letters there were no reports in the literature of allergic reactions which were due to natural latex rubber vial stoppers.
4. Research to date suggests that dry natural latex rubber is not associated with adverse events.

Those Amersham Health vial stoppers that contain latex have it in its dry form. The containers and closures used to hold Amersham Health's contrast media meet the requirements of the United States Pharmacopeia (USP). In addition, the FDA evaluates each Amersham Health product to assure it maintains its safety and efficacy over its labeled shelf life; included in this evaluation is an assessment of the effect of the container/closure system on the contrast medium. For each product, stability studies, employing highly sensitive analytical methods, are conducted to identify any compounds in the contrast medium that may have originated from the container. All stability data are reviewed by an FDA scientist whose expertise includes such fields as toxicology and pharmacology. We are not aware of any residual latex protein ever being identified as being present in any of our contrast media.

Nevertheless, we have included the following chart, which lists the dry natural latex rubber content of the stoppers of our various contrast media containers. Note that the stoppers of all Hypaque vials are latex-free, as are the entire Flexipak containers for Omnipaque and Visipaque.

*Identifies primary stopper in use.

** Identifies updated information supplied by Venusa (732) 225-7060 on 1/14/98.

Wheaton can be reached at 410-546-6441.