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Ophthalmic bioequivalence of steroid/antibiotic combination formulations
Author(s) -
Schoenwald R. D.,
Harris R. G.,
Turner D.,
Knowles W.,
Chien D.S.
Publication year - 1987
Publication title -
biopharmaceutics and drug disposition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.419
H-Index - 58
eISSN - 1099-081X
pISSN - 0142-2782
DOI - 10.1002/bdd.2510080605
Subject(s) - tobramycin , bioequivalence , cornea , aqueous humour , pharmacokinetics , chemistry , aqueous humor , chromatography , pharmacology , bioavailability , medicine , antibiotics , ophthalmology , biochemistry , gentamicin
Abstract This study compared the relative ocular bioavailability in rabbits of the antibiotic/steroid combination of 0.3 per cent tobramycin and 0.1 per cent fluorometholone acetate to each of the two single‐entity products. Two separate studies were conducted, one measuring fluorometholone acetate in cornea and aqueous humour through 240 min and the other measuring tobramycin in the cornea through 120 min. The results for fluorometholone acetate show that the combination product is 15 percent higher in AUC for the cornea than the single‐entity product (0.05< p <0.1). However, the combination product is only 4.4 per cent higher in AUC when aqueous humour levels are compared (N.S.). The single‐entity fluorometholone acetate ointment yielded cornea and aqueous humour levels which were 20 per cent ( p < 0.01) and 6 per cent (N.S.) higher in AUC than the same tissues measured after topical instillation of the suspension. Statistical treatment of the data indicated that the suspension and ointment products, were bioequivalent with respect to fluorometholone acetate in aqueous humour, but not with respect to corneal concentrations. Tobramycin was measured in the cornea following instillation of either the single‐entity solution or the combination suspension. Per cent bound (tobramycin to rabbit antibodies determined in vitro from the radioimmunoassay results) was used for statistical analyses of all group means and standard errors. The results indicated that the products were bioinequivalent.