Abstract
Purpose: :
To evaluate effects of contact lens multi-purpose disinfecting solutions (MPDS) by in vitro biocompatibility assessment using mouse fibroblast (L929) cells and in relationship to preservative uptake and release profiles with various soft contact lenses (CLs).
Methods: :
RevitaLens OcuTecTM MPDS (RO) was evaluated against two currently marketed products, Opti-Free RepleniSH® MPS (OFR) and Opti-Free® Express MPS (OFE). Five soft CLs were examined: Soflens® 38TM (Bausch & Lomb), Acuvue® Advance® (Vistakon), O2 Optix® (CIBA Vision), PureVision® (Bausch & Lomb) and Biofinity® (CooperVision) lenses. In vitro biocompatibility was assessed according to ISO 10993. MPS-treated CLs (100ml, 4 days, n=3) were placed onto L929 cells (24hrs). Cells were scored for reactivity according to USP Direct Contact Test criteria. Polypropylene pellets and latex rubber served as negative and positive controls, respectively. Comparative antimicrobial (alexidine dihydrochloride and polyquaternium-1 (PQ-1)) uptake capacity of lenses soaked in excess volume of RO, and subsequent release kinetics in buffered saline (1ml/lens, n=3-5), were determined out to equilibrium (28 days max).
Results: :
In vitro cytotoxicity showed that RO-treated PureVision® (grade 1), Acuvue® Advance® (grade 2), and O2 Optix® (grade 2) lenses were less cytotoxic compared with OFR and OFE (grade 3-4). All MPS-treated Soflens® 38TM CLs demonstrated low cytotoxicity scores (grade 2). MPS-treated Biofinity® CLs displayed moderate cytotoxicity (grade 3-4). Lens uptake of alexidine ranged from 0 to 4.1 µg/mg dry lens showing Soflens®38 < O2 Optix® < Acuvue® Advance® < Biofinity® < PureVision®. Lens release of alexidine ranged from 6.6 to 30.9 ng/mg dry lens showing O2 Optix® < PureVision® < Acuvue® Advance® < Biofinity® < Soflens®38. No quantifiable uptake or release of PQ-1 from lenses was found.
Conclusions: :
RO was found to be less cytotoxic in a standard in vitro model employing saturation levels of active entities than OFR or OFE in MPS-CLs biocompatibility, as defined by lower in vitro cytotoxicity on L929 cells. Cytotoxicity scores with RO did not correlate with preservative uptake, but a weak correlation with alexidine dihydrochloride release was observed.
Keywords: contact lens • cornea: basic science