Abstract
Purpose: :
Molecular imprinting has been used to prolong drug release in drug delivery applications. Hyaluronic acid (HA) has been shown to decrease lysozyme sorption and improve wettability in model contact lenses when used as an internal wetting agent. It was of interest to investigate the release of imprinted HA to determine if imprinting prolonged HA release and if this released HA decreased lysozyme sorption.
Methods: :
Model conventional (pHEMA) and silicone (pHEMA/TRIS) hydrogels were synthesized. HA was added to the reaction mixture prior to UV polymerization. The release of HA into PBS was measured using UV Spectroscopy at 280 nm. Throughout the release, hydrogels were removed from PBS, dried and then incubated with radiolabeled lysozyme for 2 hrs (pHEMA) and 24 hrs (pHEMA/TRIS) to determine if the released HA could decrease sorption.
Results: :
HA (35 and 910 kDa) was released from pHEMA hydrogels for 14 days. The lysozyme sorption ranged from 5.26 ± 0.32 to 13.49 ± 0.77 µg for 35 kDa HA and 10.94 ± 1.11 to 23.81 ± 3.29 µg for 910 HA. In both cases, these hydrogels showed a significant decrease in sorption (p<0.002) compared to the controls that sorbed 42.54 ± 10.85 µg. HA (4.7 kDa) was released from pHEMA/TRIS hydrogels for 25 days. The lysozyme sorption ranged from 6.88 ± 1.42 to 17.60 ± 2.50 µg, which was, with one exception, significantly less (p<0.05) compared to the control hydrogels that sorbed 26.06 ± 8.56 µg.
Conclusions: :
Molecular imprinting prolongs HA release from model contact lenses and decreases lysozyme sorption.
Keywords: contact lens • cornea: tears/tear film/dry eye • cornea: epithelium