Conformational and Quantitative Characterization of Lysozyme Extracted from Galyfilcon and Senofilcon Silicone Hydrogel Contact Lenses

PURPOSE: To compare two solvents for retrieval of lysozyme deposited on a silicone hydrogel (SH) contact lens material galyfilcon A (GA; Acuvue Advance). METHODS: Two buffers used were 50:50 acetonitrile/0.02% trifluoroacetic acid (buffer 1) and 50:50 acetonitrile/50 mM NaOH (buffer 2). RESULTS: Extraction efficiency from GA lenses was 74% (buffer 1) and 83% (buffer 2). Buffer 2 decreased lysozyme activity > buffer 1. Ex vivo GA lenses showed total protein deposition of 2-16 microg/lens with total lysozyme deposition of 0.3-3.9 microg/lens. CONCLUSIONS: We have developed a low acid strength extraction buffer that can be used to efficiently extract active lysozyme protein from novel siloxane-based contact lens materials.