title: Scintigraphic assessment of an ophthalmic gelling vehicle in man and rabbit.
abstract: Studies of the rate of clearance of a gellan gum formulation (Gelrite) radiolabelled by the inclusion of technetium-99m labelled diethylenetriaminepentaacetic acid were carried out in volunteer subjects and in rabbits. Disposition was followed by gamma scintigraphy and compared with 0.5% w/v hydroxyethylcellulose (HEC) solution and isotonic saline administered to the same subjects. Clearance of all solutions was found to follow bi-exponential kinetics with differences in clearance rates between the two species studied. A significant retention of the gellan gum formulation compared to HEC (p = 0.006) or saline (p = 0.009) was noted in man, but not in the rabbit. In this latter species the HEC showed greater retention compared to Gelrite. The species-specific differences in the precorneal residence of the formulations are attributed to the different physiological responses following instillation of solutions into the eye.
authors.affiliation: Department of Physiology & Pharmacology, Medical School, Queen's Medical Centre, Nottingham, UK.
authors.forename: J L
authors.initials: JL
authors.lastname: Greaves
authors.forename: C G
authors.initials: CG
authors.lastname: Wilson
authors.forename: A
authors.initials: A
authors.lastname: Rozier
authors.forename: J
authors.initials: J
authors.lastname: Grove
authors.forename: B
authors.initials: B
authors.lastname: Plazonnet
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002482:Cellulose / Q000031:analogs & derivatives / Q000493:pharmacokinetics; D003315:Cornea / Q000000981:diagnostic imaging / Q000378:metabolism*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D009883:Ophthalmic Solutions; D011135:Polysaccharides, Bacterial / Q000493:pharmacokinetics*; D011817:Rabbits; D011877:Radionuclide Imaging; D011897:Random Allocation; D012965:Sodium Chloride / Q000493:pharmacokinetics; D013670:Sodium Pertechnetate Tc 99m
chemical_list: D009883:Ophthalmic Solutions; D011135:Polysaccharides, Bacterial; D012965:Sodium Chloride; C048288:gellan gum; D002482:Cellulose; C002283:hydroxyethylcellulose; D013670:Sodium Pertechnetate Tc 99m