Topical preservative-free ophthalmic treatments: an unmet clinical need

ABSTRACT

Introduction: The main role of preservatives in eyedrops is to ensure sterility and microbiological integrity of the drug, and to facilitate the penetration of active compounds into the eye. However, several studies documented significant toxic effects induced by preservatives, especially on the ocular surface. Consequently, most of the ophthalmic medications became progressively available in preservative-free (PF) formulations.

Areas covered: We analyzed pre-clinical and clinical studies on PF eyedrops with particular attention to common chronic diseases such as dry eye and glaucoma. We discussed about the pros and cons of using PF eyedrops, in terms of efficacy, safety, and social-economic aspects.

Expert opinion: There are still unresolved issues that make hard for PF medications to definitively conquer the drug market. Despite robust pre-clinical evidences of less toxicity, the low number of randomized clinical trials does not permit to state that PF eyedrops have, in clinical practice, a similar efficacy or a higher safety compared to preserved forms. These aspects limit their use to chronic diseases requiring long-term therapies with multiple daily instillations, especially in the presence of concomitant ophthalmic diseases that expose to a risk of ocular surface worsening.

KEYWORDS:

• Dry eye
• glaucoma
• ocular surface disease
• preservative-free eyedrops
• preservatives

Article highlights

1. Preservatives ensure sterility and microbiological integrity of the eyedrops and facilitate the penetration of active compounds into the eye. However, they induced significant toxic effects especially on the ocular surface.

2. Patients requiring long-term therapies for chronic diseases such as glaucoma, dry eye, or inflammatory ocular surface diseases represent the ideal candidates for preservative-free formulations.

3. Preservative-free topical medications spread suffers from sterility, cost-related, and patient-related issues, especially in cases of chronic ocular diseases.

4. There is a need for spontaneous RCTs to identify the effectiveness of preservative-free eyedrops compared to preserved medications.

5. Alternative drug delivery system that release the medication continuously and that avoid self-administration will be the treatment of choice in the distant future if supported by evidence-based medicine in term of safety and efficacy.

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Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.