Abstract
Abstract: :
Purpose: To assess the passive cleaning efficacy of various multipurpose solutions (MPS) for hydrogel contact lenses using an in vitro lysozyme deposition model. Methods: The solutions assessed included AQuify®, ReNu® MoistureLocTM, ReNu MultiPlus®, Complete®, Complete® Moisture Plus, SolocareTM, SolocareTM Plus, Opti–Free®, Opti–Free® Express® and a test formulation. Acuvue 2 lenses (FDA Group IV) were used to deposit with an in vitro lysozyme deposit model. Each lens was soaked with a 5 ml lysozyme solution (1.5mg/ml in phosphate buffered saline, pH 7.4) at 37oC for 24 hours. No rubbing/rinsing was applied to the cleaning regimen. The lysozyme remained in the lens after the passive soaking with MPS was extracted with an extraction solvent composing of acetonitrile/trifluoroacetic acid/water in a volume ratio of 500/1/500. Quantitation of the extracted lysozyme was conducted by a fluorescence spectrophotometer with an excitation/emission setting at 280nm/346nm. Results: Time course studies demonstrated that the cleaning efficacy increased with the duration of soaking; 6 hr and overnight (16 hr) soaking achieved more significant cleaning than 2 and 4 hr soaking. Differences in cleaning efficacies were observed among various MPS; they ranged from approximately 6% to 44 %. The overall cleaning efficacy for all MPS were increased after 7–day cleaning cycle. In both cases, Opti–Free® Express® exceeded all other MPS in cleaning efficacy, whereas AQuify® and ReNu MoistureLocTM provided the lowest cleaning. These in vitro results agree with ex vivo clinical studies that have tested the cleaning efficacies of the various products. Conclusions: Using Acuvue hydrogel lenses deposited with an in vitro lysozyme deposition model, we are able to differentiate the cleaning efficacy of various MPS. Opti–Free® Express® was demonstrated to exceed all other MPS in cleaning of the contact lenses.