Ocular disposition of inulin from single & multiple doses of positively charged multilamellar liposomes: evidence for alterations in tear dynamics and ocular surface characteristics.
The effect of entrapment of inulin, a model medium molecular weight compound, in positively charged, multilamellar liposomes on ocular inulin absorption following instillation of single and multiple doses to the albino rabbit eye was studied. In spite of their affinity for the ocular surfaces, these liposomes provided 5 and 100 times lower ocular concentrations of inulin at 30 minutes post-dosing than aqueous solutions and neutral liposomes, respectively, and failed to sustain inulin concentrations in any anterior segment tissues over 120 min. This negative effect of positive liposomes on the ocular bioavailability of inulin can partly be attributed to a 2-fold faster disappearance rate from the tear pool, which more than offset their intrinsic ability to increase corneal drug permeability. For unknown reasons, multiple doses of these liposomes resulted in further reduction in ocular inulin absorption when compared with single doses.
Lee
V H
VH
University of Southern California, School of Pharmacy, Los Angeles.
Carson
L W
LW
D000042:Absorption; D000818:Animals; D005123:Eye / Q000378:metabolism*; D007328:Insulin / Q000008:administration & dosage* / Q000493:pharmacokinetics; D008081:Liposomes / Q000008:administration & dosage*; D008297:Male; D011817:Rabbits; D013666:Tears / Q000378:metabolism*
D007328:Insulin; D008081:Liposomes