title: Improved ocular penetration of gentamicin by mucoadhesive polymer polycarbophil in the pigmented rabbit.
abstract: OBJECTIVE
  To investigate whether polycarbophil, a mucoadhesive polymer of the poly(acrylic acid) type, would improve the ocular delivery of topically applied gentamicin.
  
  
  METHODS
  Two gentamicin formulations of this polymer (neutralized versus non-neutralized) and an aqueous control formulation in saline were administered to the pigmented rabbit eye. Drug concentrations in plasma, as well as in cornea, bulbar conjunctiva, anterior sclera, iris-ciliary body, aqueous humor, and vitreous humor, were measured by fluorescence polarization immunoassay.
  
  
  RESULTS
  Both polymeric formulations increased the uptake of gentamicin by the bulbar conjunctiva two times. Drug penetration into the aqueous humor was observed with only the non-neutralized polymer, probably occurring via the conjunctival-scleral pathway facilitated by intensified contact between the mucoadhesive polymer and the underlying bulbar conjunctiva.
  
  
  CONCLUSIONS
  Polymers of the poly(acrylic acid) type are potentially useful for improving topical antibiotic drug delivery, particularly when irritancy potential due to low pH can be overcome.
authors.affiliation: Department of Pharmaceutical Sciences, University of Southern California School of Pharmacy, Los Angeles 90033.
authors.forename: C M
authors.initials: CM
authors.lastname: Lehr
authors.forename: Y H
authors.initials: YH
authors.lastname: Lee
authors.forename: V H
authors.initials: VH
authors.lastname: Lee
mesh_terms: D000042:Absorption; D000180:Acrylic Resins / Q000378:metabolism; D000287:Administration, Topical; D000818:Animals; D000869:Anterior Eye Segment / Q000378:metabolism*; D003228:Conjunctiva / Q000378:metabolism; D004337:Drug Carriers; D016231:Fluorescence Polarization Immunoassay; D005839:Gentamicins / Q000008:administration & dosage / Q000493:pharmacokinetics*; D009077:Mucins; D011108:Polymers; D011817:Rabbits; D014822:Vitreous Body / Q000378:metabolism
chemical_list: D000180:Acrylic Resins; D004337:Drug Carriers; D005839:Gentamicins; D009077:Mucins; D011108:Polymers; C030312:calcium polycarbophil