Drug reservoir function of human amniotic membrane.

PURPOSE

The aim of the study was the quantitative pharmacokinetic evaluation of drug release from pretreated amniotic membrane (AM) in vitro.

METHODS

Cryopreserved AM pieces soaked in 3% ofloxacin ophthalmic solution were mounted in vertical Franz-diffusion cell system equipped with autosampler. In vitro release of ofloxacin was determined by quantitative absorbance measurement carried out with a UV spectrophotometer (wavelength 287 nm). Three groups were created according to the duration of soaking: 60 (Group 1), 120 (Group 2), and 180 (Group 3) minutes. Released amount of ofloxacin pro 1 cm(2) of AM (μg/cm(2)) was calculated in the period of 1 to 450 min.

RESULTS

Ofloxacin was detectable in the acceptor phase 1 min after mounting in all groups. Until 120 min, rapid increase of released ofloxacin could be observed. From 120 to 450 min, the amount of released ofloxacin showed a slower increasing pattern. Released ofloxacin in Group 1 was significantly lower than in Group 2 after 90 min (19.4±10.4 μg/cm(2), 51.6±20.7 μg/cm(2), respectively, P=0.044). In Group 3, cumulative drug release was higher than in Group at all timepoints. No significant difference could be demonstrated between Groups 2 and 3 at only 1 min timepoint.

CONCLUSION

Significant ofloxacin reservoir capacity of a single human amniotic layer could be demonstrated in vitro. AM acted as an ofloxacin slow release device for upto 7 h in vitro, depending on the duration of pretreatment of AM. Individual pretreatment of AM could increase beneficial effects of AM transplantation, especially in infectious keratitis.