title: Assessment of the precorneal residence of an ophthalmic ointment in healthy subjects.
abstract: 1. The precorneal residence of an ophthalmic ointment radiolabelled by inclusion of technetium-99m tin colloid was assessed in seven volunteer subjects using the technique of gamma scintigraphy and compared with a solution of 0.3% w/v hydroxypropylmethylcellulose, (HPMC) radiolabelled by inclusion of technetium-99m diethylenetriaminepentaacetic acid in the same subjects. 2. The mean half-times (+/- s.d.) of corneal residence were 6490 +/- 5404 s (108 min) for the ointment and 13 +/- 24 s for the 0.3% w/v HPMC solution (P < 0.01). 3. The area-under-curve value (AUC(0,540 s)), which reflects the total residence time of the preparation on the ocular surface, was calculated for each vehicle in each subject. The mean (+/- s.d.) AUC(0,540 s) value for the ointment was 42170 (+/- 5032)% s and for the 0.3% w/v HPMC solution it was 8394 (+/- 4641)% s (P < 0.01).
authors.affiliation: Department of Physiology and Pharmacology, Medical School, Queen's Medical Centre, Nottingham.
authors.forename: J L
authors.initials: JL
authors.lastname: Greaves
authors.forename: C G
authors.initials: CG
authors.lastname: Wilson
authors.forename: A T
authors.initials: AT
authors.lastname: Birmingham
mesh_terms: D000328:Adult; D003315:Cornea / Q000000981:diagnostic imaging / Q000378:metabolism*; D005260:Female; D006801:Humans; D065347:Hypromellose Derivatives; D008297:Male; D008747:Methylcellulose / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000493:pharmacokinetics / Q000494:pharmacology; D009824:Ointments; D009883:Ophthalmic Solutions / Q000008:administration & dosage / Q000493:pharmacokinetics*; D011877:Radionuclide Imaging; D016284:Technetium Tc 99m Pentetate; D014783:Viscosity
chemical_list: D009824:Ointments; D009883:Ophthalmic Solutions; D065347:Hypromellose Derivatives; D008747:Methylcellulose; D016284:Technetium Tc 99m Pentetate