Alcon Laboratories has voluntarily recalled its Systane Free Liquid Gel lubricant eye drops. The 5 million bottles of over-the-counter product have been pulled from the American market due to 11 individual consumer reports of foreign material in the bottle. Other Systane formulations are not affected, and no ocular infections due to the recalled product have been reported.

The company tested the 11 bottles of product and found the foreign material to be mold. In a letter to health-care practitioners, Alcon explains that the source of the mold is one of the antimicrobial ingredients: aminomethyl propanol (AMP), a nitrogen-based compound. The other antimicrobial agents used in Systane Free are borate, sorbitol and zinc; this combination was intended to replace the need for preservatives in Systane Free.

David Meadows, Ph.D., Alcons vice president of research for consumer products, explains: AMP is designed to hold the pH at a specific level; we used it to maintain the pH at 7.9 during storage. It was a good complement to the sodium borate in the system.

But, the nitrogen and carbon groups in AMP are substrates for mold growth, he says. The AMP was included in the solution to act as an antimicrobial buffer, but its possible that the lack of a stronger acidic component actually allowed the nitrogen-based AMP to promote microbial growth in certain environments and usage circumstances, Dr. Meadows adds. We think that, without the AMP, the microbial growth would not have occurred.

No infection has been reported in any of the cases of contamination, and the characteristics of the mold do not seem to foster infection, but Alcon promptly pulled the product off the market. We took this voluntary action even though it is unlikely that eye infections would occur as a result of this issue, says Kevin Buehler, Alcons senior vice president and chief marketing officer.

The main thing with this product is that its sterile when its made; the contamination occurred when it was in use, we believe, says Dr. Meadows. The bottle, once its opened, should be stored in clean conditions. With those returned to us, the care wasnt at the level that we hoped for. But, we need to make sure that our product is at the level where it can stand even those conditions, he says.

Since the contamination stems only from the product formulation and not the manufacturing process, the recall is limited to Systane Free Liquid Gel; other formulations of Systane lubricant eye drops are not affected. The original Systane includes the preservative Polyquad (polyquaternium-1), which Systane Free replaced with the buffering combination of borate, sorbitol, zinc and AMP. Alcons other preservative-free product, Travatan Z, does not contain AMP or any nitrogen source, and is unaffected by the complications pertaining to the recall of Systane Free Liquid Gel, the company says.

Alcon has published an advisory letter to all health-care practitioners; in this letter, available online, the company asks that all trade sizes and samples of Systane Free be discarded as well, and provides instruction on how to properly do so.

The company asks consumers who have any bottle of Systane Free Liquid Gel to immediately discontinue use and to either call 1-866-608-3936 or visit www.systane.com for instruction on returning the product in exchange for a 15ml bottle of the original formulation of Systane lubricant eye drops. The company recommends that any practitioners whose patients use Systane Free instead offer the original formulation of Systane.

But, a replacement for Systane Free is in the works. We are considering alternate formulations that would provide the same caliber of performance, says Dr. Meadows.