Caprylyl glycol in eye drops

Caprylyl glycol is the common ingredient name for 1,2-octanediol, an eight-carbon chain with alcohol groups on its first two carbons, as PubChem records it. It’s the first of 10 inactive ingredients on Quell’s Drug Facts panel, purely because the list is alphabetical. The label doesn’t give it a stated role or an amount, and it doesn’t describe it as a preservative.

What is caprylyl glycol?

PubChem, the free chemistry database run by the National Institutes of Health, lists the compound under the name 1,2-octanediol and describes it simply as an octanediol. Break that name down and it explains itself. “Octane” means a chain of eight carbon atoms. “Diol” means the molecule carries two alcohol groups. And “1,2” says those two groups sit on the first and second carbons, side by side at one end of the chain.

“Caprylyl” comes from caprylic acid, the old name for the eight-carbon fatty acid now usually called octanoic acid, and “glycol” is a general word for a molecule with two alcohol groups. So caprylyl glycol and 1,2-octanediol are two ways of naming the same thing: one from ingredient-label tradition, the other from systematic chemistry.

Where it sits on Quell’s label

Here’s the complete inactive list as printed: Caprylyl Glycol, Dead Sea Salt (Sodium Chloride), Emu Oil, Glyceryl Laurate, Glyceryl Undecylenate, Manuka Honey, Polaxamer 188, Sterile Water, Terminalia Chubula and Tromethamine. Federal rules for OTC drug labels, in 21 CFR 201.66, have inactive ingredients listed alphabetically, so a name starting with C goes first. Its place says nothing about how much is in the bottle; the label doesn’t list amounts for any inactive ingredient. Only the actives carry their strengths: Glycerol (1.0%), Polysorbate 80 (1.0%) and Light Mineral Oil (0.5%).

Is caprylyl glycol a preservative?

This is the question people actually type, and the answer depends on what you’re asking. On Quell’s label, no: it’s listed as an inactive ingredient and nowhere described as a preservative. Quell is presented as a preservative-free formula, a phrase that refers to leaving out the added preservatives some multi-use drops rely on. We won’t go beyond what the label says about any single inactive ingredient’s job.

What preservative-free does mean for you is care with the bottle. The label’s instruction is plain: Do not touch tip of bottle to any surface to avoid contamination. Recap the bottle after each use and keep it within the storage range: Store between 15° to 30°C (59° to 86°F). What preservative-free means goes through the term in more detail.

Caprylyl glycol in other products

If the name looks familiar, it may be because you’ve seen it on skin care or cosmetic labels, where it turns up often. An ingredient appearing in a moisturizer and in an eye drop doesn’t mean the two products are alike, or that the ingredient does the same thing in both. Each finished product is made to its own specifications, and an eye drop is a sterile drug. Never put a skin product near your eyes to “get the same ingredient.”

How it relates to Quell’s other ingredients

• It isn’t one of the three actives; those are Glycerol (1.0%), Polysorbate 80 (1.0%) and Light Mineral Oil (0.5%).
• It isn’t one of the natural ingredients the formula is known for, like emu oil and manuka honey.
• It shares the eight-carbon “capryl” root with caprylic acid, but it’s a diol, not a fatty acid or an oil.
• Like every other inactive ingredient, it’s named on the panel without a stated purpose.

What the formula as a whole is for

The label’s Uses line reads: For use as a protectant against further irritation or to relieve dryness of the eye. Quell is designed to reinforce the tear film’s oil layer to help reduce moisture loss, and the directions are: Apply 1 drop 3 times per day in each eye. That’s the full picture the label gives. If you want a deeper chemistry answer about a specific inactive ingredient than this guide offers, Aurora Pharmaceuticals, LLC is reachable at 615.465.6041, M–F 9AM–5PM CST, and a pharmacist can talk you through the label in person.

Sensitivities and when to stop

If you’ve reacted to products listing caprylyl glycol or 1,2-octanediol before, show Quell’s panel to a pharmacist before trying it. Separately, the label carries its own caution: Caution should be used in those with egg or bird allergies — For use in the eyes only. And its stop-use line covers any reaction: Stop use and ask a doctor if you feel eye pain or changes in your vision, if irritation or redness continues, or if the condition worsens or persists for 72 hours.

The full label is on our Drug Facts page, and the inactive ingredients section explains how that part of any panel works.