Radiochemical studies on contact lens soilation. I. Lens uptake of14C-lysozyme from simple and complex artificial tear solutions

Abstract

A systematic study has been made of the uptake of lysozyme by various contact lens materials. Lens uptake of 14C-methylated lysozyme was assessed using simple to complex artificial tear solutions. The data reflect prominent uptake by Group IV (ionic, high-water-content) hydrogel lenses, consistent with the literature. This includes protein on the lens surface and in the lens matrix, the former being estimated at about 33% of the total deposit for the DuraSoft 3 lenses used. Uptake appears to be contingent upon the nature of the lens material, the composition of the deposit model used, and the duration of lens exposure to the artificial tear solution.

Kinetics ofIn VitroLysozyme Deposition on Silicone Hydrogel, PMMA, and FDA Groups I, II, and IV Contact Lens Materials

“…1,2,48 The principal advantages of radiolabeling through the ICl method is that the number of potential oxidation steps in which 125 I is transferred to the protein is limited. During the time of addition to the reaction mixture, iodine atoms are already in a reactive state, and the number of substitution or oxidation reactions that can occur is equal to the number of active iodine atoms.…”

“…The deposition of lysozyme on etafilcon A may also be due to increased affinity of the material for protein uptake. Previously published in vitro studies investigating the kinetics of protein deposition on conventional hydrogel contact lens materials, using artificial tear solutions containing lysozyme 1,2,32,33,37,38,48 or albumin, 1,34,35 indicate that the proteins deposit rapidly on hydrogel materials, occurring within minutes of exposure. 1,32,34,35,37,48 Lysozyme accumulated rapidly on etafilcon, reached a maximum on the seventh day, and then maintained a plateau, with no further increase occurring (Fig.…”

Quartz crystal microbalance study of protein adsorption kinetics on poly(2-hydroxyethyl methacrylate)

“…In terms of conventional contact lenses, group I lenses (low water content, non-ionic) such as pure polyHEMA typically adsorb the least amount of protein [16]. An important consideration is that for certain lenses (particularly group IV) proteins such as lysozyme, major basic protein, and lactoferrin have been known to penetrate into the matrix of the hydrogel [17][18][19][20]. While some macromolecular buildup can be removed, it is questionable as to the efficacy of commercial cleaning solutions for multi-use contact lenses.…”

Extraction Efficiency of an Extraction Buffer Used to Quantify Lysozyme Deposition on Conventional and Silicone Hydrogel Contact Lens Materials

“…Table 2 shows the concentrations of various tear components in the artificial tear solution and the concentration of various artificial tear solution components from previous in vitro doping experiments, for comparative purposes. 38,39 The simple lysozyme doping solution was prepared at a concentration of 1.9 mg/mL by using phosphate buffered saline (PBS) at a pH of 7.4. Lysozyme was labeled with 125 I by using the iodine monochloride method, as described previously.…”