Use of Preservatives
Preservatives have been in use since the 1970s when regulatory authorities instituted antimicrobial usage in multi-dose containers to prevent eye infections and sustain drug potency.1
The table below displays some preservatives in use today, where benzalkonium chloride (BAK) is the most common variety used in 70% of eye drops.2 BAK is a quaternary ammonium surfactant used in concentrations of 0.004% to 0.025% to break down bacterial cell structures and prevent microbial growth.3
Preservative | Class | Medication Used | Brand Name | Preservative Concentration |
Benzalkonium Chloride (BAK or BAC) | Quaternary Ammonium | Latanoprost Bimatoprost Olopatadine Artificial Tear | Xalatan Lumigan Patanol Advanced Eye Relief | 0.02% 0.02% 0.01% 0.01% |
Polyquaternium-1 (Polyquad or PQ1) | Detergent | Travoprost Artificial Tear | Travatan Tears Naturale II | 0.01% N/A |
Sodium Chlorite (Purite) | Oxidant | Brimonidine | Alphagan P | N/A |
Potential Challenges with Preservatives
The effectiveness to which preservatives like BAK attack microbes and bacteria unfortunately also may present adverse effects to the cornea, conjunctival epithelium, and trabecular meshwork.4 BAK-filled eye drops can be most problematic when used to treat chronic conditions such as glaucoma and dry eye disease, where long-term exposure may lead to deleterious effects.5,6
- 80% toxicity level increase of cultured cornea and conjunctiva cells after exposure to BAK at 0.025%.4
- 53% reduction of cultured trabecular meshwork (TM) cells after exposure to BAK 0.020%7, which may cause further TM degeneration and potentially reduce the effectiveness of IOP-lowering glaucoma medications. 8
- 59% of glaucoma patients treated with BAK-preserved medications report symptoms of OSD (Ocular Surface Disease includes dry eye, lid disease, conjunctivitis, and keratitis). 9
- 7 out of 10 patients feel significantly reduced OSD symptoms when using glaucoma medications free of BAK preservatives.10
Available Preservative-Free Formulations*
Along with the use of single-dose vials which can be more costly and cumbersome to maintain, ImprimisRx® has several preservative-free ophthalmic formulations* (Simple Drops® and Total Tears®) utilizing our PureFlow® technology.11
Several factors affect tolerance of preservatives, including their concentration, frequency of the use of the medication, duration of treatment, the physiologic state of the cornea, the use of contact lenses, and the number and type of concurrent medications.12 Consult with a medical professional about which preservative-free options from ImprimisRx® may be right for you.
*For professional use only. ImprimisRx® specializes in customizing medications to meet unique patient and practitioner needs. ImprimisRx dispenses only to individually identified patients with valid prescriptions. No compounded medication is reviewed by the FDA for safety or efficacy. ImprimisRx does not compound essential copies of commercially available products. References available upon request.