Purpose: The aim of this study was to develop a model to investigate the permeability of the amniotic membrane (AM) to ofloxacin eye drops, a widely used topical antibiotic in ocular surface disease after AM transplantation.
Methods: AM pieces on cellulose acetate filter membranes were mounted in a vertical Franz-diffusion cell system equipped with an autosampler. In vitro release of 300 mg of 3% commercially available ofloxacin ophthalmic solution was determined by quantitative absorbance measurement carried out with a UV spectrophotometer (wavelength, 287 nm). Freshly prepared and cryopreserved AMs were compared. Filter membranes without AM served as positive controls.
Results: Ofloxacin was detectable in the acceptor phase 1 minute after instillation, and a gradual increase of concentration could be detected in a period of 90 minutes in all groups. At 30 minutes 3.35% +/- 2.23% of ofloxacin penetrated the freshly prepared AM, 4.35% +/- 1.8% through cryopreserved AM compared with 17.52% +/- 3.91% filter membrane alone. At 90 minutes, penetration rates of ofloxacin were 5.04% +/- 1.11%, 5.26% +/- 3.21%, and 27.91% +/- 3.05%, respectively. Difference (P > 0.05; t-test) was not significant between freshly prepared and cryopreserved AMs. Compared with control, both membranes showed significant differences (P < 0.05; t-test) at all time points.
Conclusions: The in vitro model of the Franz-diffusion cell system was found to be applicable for drug permeability studies of human amniotic membranes to water-based solutions. The filter membrane and AM were permeable to a water-based solution of ofloxacin. Significant barrier function of the AM could be measured in ofloxacin permeability. Cryopreservation did not influence the permeability of the AM.