BUYNUZ QİŞANIN TAMLIĞINI POZMADAN RİBOFLAVİNİN STROMAYA YERİDİLMƏSİNİN EKSPERİMENTAL ÖYRƏNİLMƏSİ

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SUMMARY

Aim – to examine ribofavin concentrations in corneas from rabbits with standard and transepithelial methods and iontophoresis without disrupting the integrity of the corneal epithelium before corneal collagen cross-linking.

Material and methods
Twenty-four eyes of 12 adult New Zealand rabbits were used. They were assigned to 4 groups, each including 6 eyes. Group 1 was exposed to the standard method and given ribofavin 0.1% after epithelial debridement. Group 2 was exposed to the transepithelial method and given benzalkonium chloride (BAC), ethylenediaminetetraacetic acid (EDTA), trometamol (TRIS), hydroxypropylmethylcellulose (HPMC), and ribofavin 0.2% 3 times at 1.5-minute intervals followed by ribofavin 0.2%. Group 3 was given ribofavin 0.1% by using 1-mA electric current for 10 minutes with the help of iontophoresis without using substances disrupting the integrity of the corneal epithelium. Group 4 received the same treatment as did group 3, except that it was given ribofavin 0.2%. Following these treatments, ribofavin concentrations in corneas were measured with ultraperformance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS).

Results
Ribofavin concentrations in the cornea were higher in group 1 (42.4 6 5.4 mg/g) than in the other groups. They were signifcantly higher in group 4 (34.2 6 6.6 mg/g) than in group 2 (24.4 6 1.2 mg/g) (P = 0.009) and group 3 (23.6 6 6.1 mg/g) (P = 0.026). There was not a signifcant difference in corneal ribofavin concentrations between group 2 and group 3 (P = 0.937).

Conclusions
Intrastromal and aqueous ribofavin concentrations after administration of ribofavin 0.2% through iontophoresis without disrupting the integrity of the corneal epithelium were lower than those after the standard method, but higher than those after the transepithelial method. In this study in which ribofavin concentrations were measured with a very sensitive method iontophoresis was observed to increase the transmission of ribofavin molecules into the cornea without using substances disrupting epithelial integrity.