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View Full Version : "purified benzyl alcohol" v. BAK; topical NAC



Rojzen
01-Aug-2007, 23:35
Has anyone come across "purified benzyl alcohol" as a preservative in topical ophthalmic products (either Rx or OTC)? (I've scanned our Archives, and our reference section on Preservatives, but the reference to benzyl alcohol I've located doesn't address toxicity to corneas, etc.) I raise this because I worry that if BAK (benzalkonium chloride) is so notoriously destructive to the ocular surface, perhaps any benzene compound will be. . .

What prompts this concern is that I have accidentally come across some patent information reflecting testing of topical NAC (a 1% solution) blended with PVA (polyvinyl alcohol) for treatment of keratoconjunctivitis sicca (see, e.g., http://www.freepatentsonline.com/5510101.html), which, in turn, led me to the cataract-dissolving NAC product that has been discussed here at the Zone, on another occasion. That cataract-treatment NAC drop does not contain PVA, but its manufacturer tauts the product for dry eye; and I cannot find an NAC drop that does contain PVA.

Anyway, the NAC drop that's on the market ("Nu-Eyes") contains purified benzyl alcohol as its preservative, and I'm tentatively discouraged by that, assuming that this compound somehow functions similarly to BAK.

I've written to the Nu-Eyes company, to ask if the product can be compounded without preservatives, but I wouldn't bet on a favorable reply.

Needless to say, if I can summon some reassurance on the preservative, I may self-experiment with the NAC drop. . .

I should add that the whole meandering, here, started when I began to wonder what will happen to my already problematic eyes when I have to have cataract surgery, later in life, which, I suspect, is an inevitability. . .My otherwise healthy Mom had a disastrous post-cataract-surgery result, with severe ocular surface inflammation, a few years back. . .and I cannot imagine that DES sufferers make great candidates for anything so invasive. . .Oy (:^). . .

If I hear back from the Nu-Eyes maker regarding the preservative, I'll post immediately. . .

And if anyone is already using a topical NAC for DES, I'd love to learn more...

Rojzen
02-Aug-2007, 00:11
To my amazement, the staff at Nu-Eyes has responded quickly, and advised that benzyl alcohol is not a benzene compound, and is not related in any way to benzalkonium chloride. I hope that compatriots here will forgive my posting a chemistry question based on what turned out to be an erroneous assumption. . .Anyway, Nu-Eyes says that the concentration of benzyl alcohol in its product is 0.3%, and is sufficient only to preserve the solution for 21 days after the bottle is first opened.

I'd still love to know more about this particular preservative, but with down sides existing even for the allegedly safe ones, like those dissolving ones that presuppose that DES people have plenty of tears to supply for the dissolving :mad: , perhaps I shouldn't think too hard about this. . .

There is one testimonial at the Nu-Eyes website, btw, from a patient who appeared to be dealing with painful DES: .http://bionational.com/xcart/catalog/testimonials.html.

I would, moreover, be hugely remiss, if I didn't flag that Nu-Eyes is, apparently, being used with wild success to reverse cataracts in dogs! Now that is cause for wiggles and yelps of joy, in my book. . .(See my avatar :)