Metals Content in Eye Drops and Contact Lens Solutions by ICP-MS Application Note · PlasmaQuant MS

Introduction

Eye medications are used to diagnose, treat, and prevent eye diseases. Most eye medicines need a prescription. However, artificial tears to lubricate the eye and ocular decongestants to decrease redness are available as over-the-counter eye drops. Eye drops are most often saline solutions including medications to treat various conditions of the eye. Sometimes, they contain no medication and are meant to lubricate the eyes or to rinse out foreign bodies. Artificial tears have various formulations and viscosities. Some may contain bicarbonate ions, and varying viscosity as well as tonicity. Except for artificial tears, many of these formulations are neither soluble in aqueous nor organic media.

A contact lens solution is designed to rinse, store and clean the contact lenses. It also kills bacteria, prevents bacteria growth and keeps the contact lenses safe when they come into contact with the eyes. Solutions come in many different formulas, all aimed to accommodate slightly different needs, but mostly they all do a very similar job. Classified as parenteral medication and relatively large daily doses, the inorganic components in these pharmaceutical products must be present at low concentrations. Therefore, ICP-MS is the most appropriate technique for the determination of trace elements in eye drops.

The International Conference on Harmonization Guideline for Elemental Impurities Q3D (ICH Q3D) (1) has established maximum permitted daily exposure (PDE) limits for elemental impurities in pharmaceutical products. Table 1 shows PDE limits for oral, parenteral, and inhalation exposures of all interesting Application Note · PlasmaQuant MS elements. Besides that, ICH Q3D also states that if the total elemental impurity level from all sources in the drug product is expected to be consistently less than 30 percent of the PDE, then additional controls are not required.

This application note demonstrates the performance of the PlasmaQuant MS Q for the analysis of Class 1, 2 and 3 elements in a variety of eye drop and contact lens solutions according to USP 232, 233 regulations (2-3).