What are eye drops made of?

Most eye drops are made of purified water plus two kinds of ingredients: active ingredients, which do the product’s job, and inactive ingredients, which make the solution comfortable, stable and the right consistency. On an over-the-counter drop, FDA’s Drug Facts format lists both. Quell’s actives are Glycerol (1.0%), Polysorbate 80 (1.0%) and Light Mineral Oil (0.5%); its inactives include sterile water, salt and natural oils.

Active and inactive ingredients, in general

Every over-the-counter drug sold in the US carries a Drug Facts panel in a standard order, under FDA’s labeling rule at 21 CFR 201.66. The panel opens with the active ingredients, each with its strength and its purpose, and closes with a list of inactive ingredients. The active ingredients are the ones responsible for the drug’s stated use. Inactive ingredients don’t carry that job, but they make up most of the bottle and shape how a drop feels.

For lubricating eye drops, the active ingredients come from a short list FDA allows for over-the-counter eye products in its ophthalmic monograph, 21 CFR part 349. That list sorts them into groups such as demulcents, which are water-soluble lubricants, and emollients, which are oily ones. Glycerin, polysorbate 80 and light mineral oil all appear there.

What lubricating eye drops are made of

A typical lubricating drop is built from a handful of ingredient types. Not every product uses all of them.

• Water: the base. On a label it may appear as purified or sterile water.
• Lubricants (demulcents): water-soluble ingredients that make the drop slippery and help it spread.
• Emollients: oils that blend with the outer, oily layer of the tear film.
• Salts: to bring the solution close to the saltiness of natural tears, so it doesn’t sting.
• Buffers: to hold the solution near the right acidity for the eye.
• Emulsifiers: to keep oil and water mixed.
• Preservatives: in many multi-use bottles, to limit contamination after opening. Quell has none.

What Quell is made of

Quell’s Drug Facts panel lists three active ingredients: Glycerol (1.0%), Polysorbate 80 (1.0%) and Light Mineral Oil (0.5%). Two are lubricants and one, the light mineral oil, is an emollient. Its inactive ingredients are: Caprylyl Glycol, Dead Sea Salt (Sodium Chloride), Emu Oil, Glyceryl Laurate, Glyceryl Undecylenate, Manuka Honey, Polaxamer 188, Sterile Water, Terminalia Chubula and Tromethamine.

Mapped onto the general types above, the label shows sterile water as the base, Dead Sea salt listed as sodium chloride, tromethamine (a compound widely used as a buffer), poloxamer 188 (written on the carton as Polaxamer 188), and natural ingredients such as emu oil, manuka honey and Terminalia chebula (written on the carton as Terminalia Chubula). Each of those has its own guide: Dead Sea salt, poloxamer 188 and tromethamine, emu oil and caprylyl glycol.

Why Quell looks the way it does

Water-based drops with no oils usually look clear. Quell’s oils and natural ingredients give it a different look, and the label says so: Product appears as a milky brown solution. That’s the expected appearance, not a sign something is wrong. The label’s rule on color is about change: If this product changes color.

Reading percentages on the label

The strength beside each active ingredient is its concentration in the solution, not a measure of how well the drop works. Different brands use different strengths and combinations, so the numbers aren’t a ranking. What the percentages mean explains how to read them. Inactive ingredients are listed without strengths.

Checking ingredients for allergies

Because the full list is printed, you can check it against anything you know you react to. Quell’s label carries one specific caution: Caution should be used in those with egg or bird allergies — For use in the eyes only. That comes from the emu oil. If any other ingredient gives you pause, take the list to a pharmacist before ordering. The full panel is on the Drug Facts page.

What eye drops are not

Homemade salt water or honey from a jar is not the same as a sterile eye drop made under drug manufacturing controls, and neither belongs in your eyes. How an eye product is made and sealed matters as much as its ingredient list, which is why a sterile, sealed bottle with a full Drug Facts panel is the thing to look for.