title: Ocular Pharmacokinetics of a Novel Loteprednol Etabonate 0.4% Ophthalmic Formulation.
abstract: BACKGROUND
  Topical ophthalmic formulations of corticosteroids are commonly used to treat a variety of ocular diseases and conditions that have an inflammatory component. The purpose of this study was to evaluate the effect of the mucus-penetrating particle (MPP) technology on the pharmacokinetic profile of loteprednol etabonate in the ocular tissues of rabbits.
  
  
  METHODS
  Forty-eight New Zealand White rabbits were randomly assigned to two groups (n = 3 rabbits or 6 eyes per time point) and treated with either the novel loteprednol etabonate MPP suspension formulation, 0.4% (LE-MPP 0.4%), or the commercial Lotemax(®)-brand loteprednol etabonate ophthalmic suspension, 0.5% (Lotemax 0.5%) (Bausch & Lomb Incorporated, Inc., Rochester, NY, USA). Samples of aqueous humor, various ocular tissues, and plasma were collected from animals over a 12-h period after a single dose of the test articles. Loteprednol etabonate concentrations were assayed using liquid chromatography-tandem mass spectrometry (LC/MS/MS).
  
  
  RESULTS
  Loteprednol etabonate was rapidly absorbed into ocular tissues following administration of either formulation. A higher ocular exposure was achieved using LE-MPP 0.4%, with peak concentrations of approximately threefold higher in ocular tissues and the aqueous humor than Lotemax 0.5%.
  
  
  CONCLUSIONS
  Administration of LE-MPP 0.4% improved loteprednol etabonate pharmacokinetic profile in ocular tissues of rabbits. The results of this study support the premise that the MPP technology can be used to enhance ocular exposure for topically applied therapeutic agents. Further studies to assess the clinical efficacy and safety of the LE-MPP formulation are warranted.
authors.affiliation: Kala Pharmaceuticals, Inc., Waltham, MA, USA. lisa.schopf@kalarx.com.
authors.forename: Lisa
authors.initials: L
authors.lastname: Schopf
authors.affiliation: Kala Pharmaceuticals, Inc., Waltham, MA, USA.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Enlow
authors.affiliation: Kala Pharmaceuticals, Inc., Waltham, MA, USA.
authors.forename: Alexey
authors.initials: A
authors.lastname: Popov
authors.affiliation: Kala Pharmaceuticals, Inc., Waltham, MA, USA.
authors.forename: James
authors.initials: J
authors.lastname: Bourassa
authors.affiliation: Kala Pharmaceuticals, Inc., Waltham, MA, USA.
authors.forename: Hongming
authors.initials: H
authors.lastname: Chen
keywords: Loteprednol etabonate; Mucous; Mucus; Ocular; Ophthalmic; Ophthalmology; Pharmacokinetic; Rabbit; Steroid; Topical