Abstract
Purpose :
Corneal ulcers, an ocular emergency and a leading cause of blindness globally, require compounded off label topical antibiotics, often at an inconvenient hourly round-the-clock multiple day administration. To overcome this challenge, a topical CMHA-S gel, Ocular Bandage Gel (OBG) was evaluated as a vehicle for delivering small molecules in a more sustained-released manner compared to antibiotic solutions.
Methods :
Two small molecule antibiotics, Moxifloxacin and Besifloxacin, were used in this study. The molecules were dissolved in either PBS or OBG at a concentration of 10 mg/ml. The sample of 500 μl was transferred to a dialysis chamber with a molecular weight cutoff of 50 kDa. The dialysis chamber was placed in a 50 ml tube, which contained 10 ml of PBS. The dialysis chamber was transferred to a new tube after 1, 2, 4, and 24 hours. The dialysate was assayed for the antibiotic using UV absorption at each time point, and compared to a standard curve. The cumulative amount released over time was then calculated.
Results :
OBG slowed down the release of both Moxifloxacin and Besifloxacin, compared to PBS controls. At 4 hr, approximately 100% of the antibiotics had been released from the PBS, whereas only about had been released from OBG. By 24 hr, 80% of the Moxifloxacin and 70% of the Besifloxacin was released from the OBG. Despite the very poor water solubility of Besifloxacin compared to Moxifloxacin, the similarity in release rates indicate that the release may be more dependent on molecular weight than solubility.
Conclusions :
This study demonstrated the capability of OBG as a delivery vehicle for small molecules, including one with poor water solubility, as well as the ability to slow the release somewhat compared to a solution. Combined with OBG’s longer retention on the surface compared to a drop, this may allow for less frequent dosing. Future studies will investigate the delivery of larger molecules from OBG as well as treating additional ocular pathologies.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.