New preserving agents for ophthalmic products, cosmetics & Co.

By the very nature of preservatives, they are toxic to cells

Apart from the mucosa, the eye is the only entrance gate for microbes to the uninjured human body. Consequently, all foreign material that is intended to be applied to the eye has to be sterile.

This applies both to ophthalmic drugs and to solid state adjuvants such as contact lenses. To keep multi-dose systems free of microbes, preservatives have been added to ophthalmic products for decades.

The "safer" compounds are likely to be less effective, leading to the need for more than one preservative, which in turn may lead to new problems in the field of toxicology, compound interaction and regulatory issues.

Some Drawbacks/ Limitations of applied preservatives

cornea damage (BAC)

dry eye syndrome (even blindness) (BAC)

not effective against prominent fungi (PQ-1)

neurotoxic (Thiomersal)

hormone-like properties, potentially carcinogenic (Propyl-4Hydroxybenzonate)

cartilage toxicity (Chlorhexidine)

non-specific action - potentially dangerous to all healthy tissues (Purite)

toxicity of boric acid - no approval in the EU (SOFZIA)

While these safety and efficacy problems are serious enough, regulatory issues and bacterial resistance add further problems. Regulatory requirements have changed substantially during the past 40 years.

we have developed a new generation of preservatives for ophthalmic products

who we are

ChiroBlock Ltd. is a chemical custom synthesis service provider. We perform chemical contract research projects on behalf of our customers. This project (new preserving agents) was initiated and conducted by ChiroBlock in partnership with the University of Braunschweig (Germany)


our Idea

The development of new, gentle preservatives for different applications, but mainly for ophthalmic products. Balancing antimicrobial efficacy and toxicity could be faciliated by combining structural features of the safer poly cationic PQ-1 polymers and the more active amphilic BAC related compounds.

our Results

We have developed a number of new, potentially promising compounds. Some of them are oligomers, others discrete smaller molecules. All substances contain quarternary ammonium groups, complemented by additional structural characteristics.

The new compounds are not only active against both bacteria and fungi, but they also exhibit favourable safety profiles.

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