Comparative Toxicity of Preservatives in Ophthalmic Solutions

[stella]

I have re-read the discusion and comments on polixetonium/polyquternium-42
as found in Dr Holly's drops and realize to my relief that Dr Holly says polixetonium/polyquaternium-42 is "not to be confused with Alcons polyquaternium -1"So to come back to these researchers - It is probably polyquaternium - 1 they are talking about

Another name for polixitonium according to Cindy, is Busan 1507

It is very confusing for the unscientific lay person

As for BAK --- I would'nt let it anywhere near my eyes !

[Z351]

what's the source of information

Check your sources (i've read that many times on industry websites and the opposite from the research). If it's the industry saying that then maybe you shouldn't trust them. from what I've read BAK is bad news from drop ONE, of course drop two if worse, and so on.

"Depending upon concentration, BAK exhibited from 56% to 89% toxicity."

And it all depends on the state or your cornea and individual aspects (healing etc). I react to the first drop. Stella's doctor is probably the only person who may give competent advice knowing the state of her corneal surface, etc.

Remember that BAK is a detergent so it destroys the lipid layer from drop one.

[clairvoyant]

I think I read somewhere that as long as you don't do more than 4 drops a day of it you are fine. (bak that is)

Also if you think about it, if it is in steroids then it will likely be negated from the healing iniated by the steroids.

[stella]

I wish i did not know about those experiments posted by Z351!

Why would someone as intellegent and respected as Dr Holly include anything in his drops that would harm the eye surface?

What is someone like myself supposed to do - --
I have finally found an effective eye drop that gives me relief and now i am told it could be harmful to my eyes ????

Who do i believe ?
Dr Holly or these researchers ?

Any comments gratefully recieved

[Z351]

EDTA with minimal toxicity (from 6% to 59%) was indistinguishable from SP.

CONCLUSIONS: Generally, the order of decreasing toxicity at the most commonly used concentrations: Thi (0.0025%) > BAK (0.025%) > Cbl (0.25%) > MP (0.01%) > SP (0.0025%) approximately EDTA (0.01%). Even at low concentration, these agents will cause some degree of ocular tissue damage.

PMID: 19284328 [PubMed - in process]

Minimal toxicity doesn't mean none. I prefer to use preservative free vials in any case. But obviously if you compare other preservatives with BAK then you'll find it's always much much worse.
http://preservative.free.fr/English/consequences-per-preservative.htm
http://preservative.free.fr/English/...servatives.htm

You'll find some references to EDTA. Maybe we could start by banning BAK...
don't forget to sign our petition.

[stella]

I think I can answer my own questions ----

I looked up the question i asked Dr Holly back in October about EDTA and my concerns about it
I did not realize he had replied in January
His reply was very reassuring You can look it up under Q and Answers Dr Holly
Basically he says it is harmless - a chelating agent which helps enhance the preservative which is polyquaternium in clinitas

Then i looked up his answer to Rebeccas question on the differece between polyquaternium and polixetonium (basically the same preservative )
THAT was very reassuring (you can read the whole thing if you put polyquaternium into the search box - that will get you Rebeccas question )
He says amounst other things that polixetonium (polyquaternium) is - a highly effective anti-microbal that does'nt damage the ocular surface or tear film with long term use
It is used as a contact lens disinfectant to facilitate wetting of the surface to make it more comfortable
Well thats good enough for me !

I hope this reassures the other worried users of Dr Holly's drops It has reassured me and i do intend to use it indefinately

[stella]

Very informative Scout -thanks !
However it leaves me ,and everyone else using Dr Holly's drops with a problem
They are preserved - I quote from Clinitas ultra 3 - polyquaternium 42 and disodium edetate
I understand that these are minimally damaging and also have anti microbal qualities which is good
I DO hope so as i intend to use them indefinately
Anyone any comments or better still reassurance that they are OK ???

[Z351]

Even at low concentration, these agents will cause some degree of ocular tissue damage.

PMID: 19284328 [PubMed - in process]

And we don't need that (tissue damage), do we?
Another good reason to sign this online petition:
http://associationgeniris.free.fr/in...joomlapetition

Everyone may sign as said elsewhere.

[indrep]

A presentation at ARVO stated similar findings. The excuse docs give for not being more forceful with patients is: "patient wants the cheapest eye drop." I think patients deserve to know what's bad for their eyes. then if they choose they can continue to use a product that doesn't help. But the doctor should inform the patient.

[Scout]

http://www.ncbi.nlm.nih.gov/pubmed/1...ubmed_RVDocSum
J Ocul Pharmacol Ther. 2009 Apr;25(2):113-9.

Comparative toxicity of preservatives on immortalized corneal and conjunctival epithelial cells.
Epstein SP, Ahdoot M, Marcus E, Asbell PA.

Department of Ophthalmology, Mount Sinai Medical Center, New York, NY 10029-6574, USA. seth.epstein@mssm.edu

PURPOSE: Nearly all eye drops contain preservatives to decrease contamination. Nonpreservatives such as disodium-ethylene diamine tetra-acetate (EDTA) and phosphate-buffered saline are also regularly added as buffering agents. These components can add to the toxicity of eye drops and cause ocular surface disease. To evaluate the potential toxicity of these common components and their comparative effects on the ocular surface, a tissue culture model utilizing immortalized corneal and conjunctival epithelial cells was utilized.

METHODS: Immortalized human conjunctival and corneal epithelial cells were grown. At confluency, medium was replaced with 100 microL of varying concentrations of preservatives: benzalkonium chloride (BAK), methyl paraben (MP), sodium perborate (SP), chlorobutanol (Cbl), and stabilized thimerosal (Thi); varying concentrations of buffer: EDTA; media (viable control); and formalin (dead control). After 1 h, solutions were replaced with 150 microL of MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazonium bromide). After 4 h, solutions decanted, 100 microL of acid isopropanol added, and the optical density determined at 572 nm to evaluate cell viability.

RESULTS: Conjunctival and corneal cell toxicity was seen with all preservatives. Depending upon concentration, BAK exhibited from 56% to 89% toxicity. In comparison, Cbl exhibited from 50% to 86%, MP from 30% to 76%, SP from 23% to 59%, and Thi from 70% to 95%. EDTA with minimal toxicity (from 6% to 59%) was indistinguishable from SP.

CONCLUSIONS: Generally, the order of decreasing toxicity at the most commonly used concentrations: Thi (0.0025%) > BAK (0.025%) > Cbl (0.25%) > MP (0.01%) > SP (0.0025%) approximately EDTA (0.01%). Even at low concentration, these agents will cause some degree of ocular tissue damage.

PMID: 19284328 [PubMed - in process]