Abstract
Purpose :
A newly designed surface wettable silicone hydrogel (SiHy) contact lens material was studied based on sustained release of amphiphilic rewetting agent, EOBO [poly(oxyethylene)-co-poly(oxybutylene)]. The purpose of this study was to evaluate the uptake and release profiles of EOBO from the SiHy lens material.
Methods :
The EOBO uptake profile into the lens matrix was evaluated with a fluorescence microscope using a fluorescent EOBO (Figure 1). EOBO release from the lens to a fixed volume of phosphate buffered saline (PBS) was measured with high-performance liquid chromatography (HPLC) at various times (Figure 2). Fick’s second law and EOBO concentration measurements at equilibrium were used to obtain the diffusion coefficient and the partition coefficient of EOBO.
Results :
Diffusion coefficient of EOBO measured was ~10-11 cm2/s, which is about three to four magnitudes less than that of polymers with similar hydrodynamic radius. In addition, the lens partition coefficient of over 100 for EOBO indicated strong favorable interactions between EOBO and the hydrogel lens matrix. Lower molecular weight or more hydrophilic portion of EOBO preferentially released, whereas higher molecular weight or less hydrophilic EOBO practically retained within the bulk material. The unique interaction between the lens material and the rewetting agent contributed to the prolonged release of EOBO from the SiHy material. Results showed that EOBO released continuously from the bulk material for more than 7 days (Figure 2).
Conclusions :
An in-vitro study and theoretical modeling were conducted on a new surface wettable SiHy contact lens material with a sustained release rewetting agent EOBO to demonstrate the feasibility of an enhanced re-wettable contact lens material. The unique interaction between the lens material and the rewetting agent contributed to the sustained release of EOBO from the SiHy lens material for more than 7 days.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.