solution focus

Bio-Inspired Solution

Multi-purpose contact lens solution mimics eye's biology.

Bruce Anderson, O.D., F.A.A.O.

Biomimetics is the study of the structure and function of biological systems as models for the creation of new materials and machines. This has led to many developments in industry and medicine, such as Velcro and the artificial heart. Through the use of biomimetics, Bausch + Lomb has developed a new multi-purpose solution: Biotrue.

Here, I explain how this new solution mimics the natural properties of the eye, its potent disinfecting components and how its packaging may instill patient compliance.

Eye's natural biology

Inspired by the biology of the eye, Biotrue mimics the eye's natural, healthy state in three primary ways:

1. pH balance. Human tears usually maintain a pH level of between 7.3 and 7.7. Biotrue provides a pH of 7.5.

In fact, in clinical trials, 81% of patients who used the solution reported it felt like their natural tears. Biotrue's dual disinfectants' ability to disinfect is enhanced and optimized by this normalized pH.

2. hyaluronan. This is a naturally occurring biological wetting agent, which is found throughout the body, as well as in the eyes. Hyaluronan has the physical property to envelop the contact lens (both hydrogel and silicone hydrogel materials) and provide enhanced wetting and moisture to the lens' surface for up to 20 hours. As a result, it eases the friction the eyelid has over the contact lens upon blinking.

3. protein preservative formulation. Biotrue supports beneficial tear proteins and promotes homeostasis.

Specifically, the solution preserves lysozyme, which is essential for antimicrobial activity. In addition, the formulation clears the contact lens of denatured proteins, which can contribute to inflammation of the lids and conjunctiva. This results in the patient experiencing a clean-feeling lens and minimal irritation.

Because all three bio-inspired elements result in enhanced patient comfort, the solution may prevent some patients from dropping out of lens wear.

Biotrue Multi-Purpose Solution PRESERVATIVES AND ANTIMICROBIALS: Polyaminopropyl biguanide and polyquaternium-1 RECONDITIONING SYSTEM: Hyaluronan and poloxamine CLEANING AGENTS: Poloxamine and sulfobetaine BUFFERING AGENTS: Boric acid and sodium borate DEMULCENT: None (nothing in Biotrue is officially recognized as an ophthalmic demulcent) OSMOLARITY AGENT: sodium chloride

Strong disinfectant

In addition to mimicking the eye's natural biology to provide contact lens comfort, Biotrue includes a strong dual disinfectant whose efficacy is analogous to a peroxide solution.

Biotrue contains a combination of polyaminopropyl biguanide and polyquaternium-1. This combination exceeds the Food and Drug Adminstration (FDA) and International Standards Organization's (ISO) stand-alone procedure for disinfecting products. (FDA/ISO stand-alone testing qualifies the disinfection efficacy of various multipurpose solutions based on log reductions or kill rates of challenge organisms.)

Additionally, Biotrue has been shown to be very effective in clinical isolate testing against bacteria and fungi. (Clinical isolates are microbial strains collected from clinically worn contact lenses, lens cases and infected eyes.) Biotrue proved highly effective against microbes, such as Staphylococcus aureus, methicillin-resistant S. aureus (MRSA) and Fusarium solani. It also demonstrated over a three log reduction of Acanthamoeba polyphaga trophozoites and cysts.

Instills compliance

Since Biotrue comes in a clear bottle, it enables patients to become aware ahead of time when they need to replace their current bottle. As a result, it has the likelihood of improving compliance to the solution, via consumer behavior.

Because Biotrue mimics the biology of the eye — enhancing comfort — provides a strong disinfecting ability and has the probability of instilling compliance due to its clear packaging, I've found it's an ideal multi-purpose solution to offer to patients. OM

This article was co-authored with Dr. Anderson by OM contributing editor Melissa Short, who obtained much of the information with interviews and e-mails.