A preliminary study of the adsorption and release of preservatives by contact lenses and collagen shields.

PURPOSE: We evaluated the adsorption and release of preservatives and a beta-blocking agent (metipranolol) by three different contact lens materials and two collagen shields.

METHODS

We recorded the ultraviolet absorption spectra of these materials before, during, and after extended exposure to pharmaceutical preparations of artificial tears, beta-blocking eye drops, and a contact lens cleaning solution. The presence of preservatives and active ingredients was demonstrated by thin layer chromatography.

RESULTS

Significant differences were observed depending on the nature of the absorbant materials and the preservatives. Soft lenses showed the greatest affinity for benzalkonium chloride and metipranolol but also readily released them.

CONCLUSIONS

This preliminary study points out that rinsing with a sodium chloride isotonic solution without preservatives has an important place in daily contact lens care.