Gelatinized core liposomes: A new Trojan horse for the development of a novel timolol maleate glaucoma medication

Int J Pharm. 2019 Feb 10:556:192-199. doi: 10.1016/j.ijpharm.2018.12.015. Epub 2018 Dec 12.

Abstract

Glaucoma treatment with ocular medications requires overcoming the corneal barrier to drug penetration. Liposomes have a great corneal penetration ability and affinity while suffering from poor stability and low entrapment of hydrophilic drugs accompanied by rapid drug release. This work aims to develop a new, effective and stable glaucoma medication with sustained drug release properties; Timolol maleate gelatinized core liposomes. A full factorial design was utilized to study the effects of three formulation variables on drug loading and vesicle particle size. Vesicles were prepared by the thin-film hydration method, and characterized for in-vitro drug release and stability. Intra-ocular pressure (IOP) reduction was evaluated in-vivo on glaucomatous rabbit's eyes. The safety profile was assessed using histopathological examinations. Gelatin significantly increased the drug entrapment percentage reaching 50% with a particle size of 38.81 µm. Sustained drug release was recorded compared to a marketed product and to a conventional liposomal formulation. The prepared vesicles caused the highest reduction in IOP accompanied by safe histological findings. This work provided a new, safe and effective ocular glaucoma medication; Timolol maleate gelatinized core liposomes, solving the main problems of ocular liposomal formulations of hydrophilic drugs, suitable for the pharmaceutical industry and comprising abundant and relatively cheap components.

Keywords: Gelatin; Glaucoma; Liposomes; Ocular; Sustained; Timolol.

MeSH terms

  • Adrenergic beta-Antagonists / administration & dosage*
  • Adrenergic beta-Antagonists / pharmacology
  • Adrenergic beta-Antagonists / toxicity
  • Animals
  • Chemistry, Pharmaceutical / methods
  • Cornea / metabolism
  • Delayed-Action Preparations
  • Disease Models, Animal
  • Drug Liberation
  • Drug Stability
  • Gelatin / chemistry
  • Glaucoma / drug therapy*
  • Hydrophobic and Hydrophilic Interactions
  • Intraocular Pressure / drug effects*
  • Liposomes
  • Particle Size
  • Rabbits
  • Timolol / administration & dosage*
  • Timolol / pharmacology
  • Timolol / toxicity

Substances

  • Adrenergic beta-Antagonists
  • Delayed-Action Preparations
  • Liposomes
  • Timolol
  • Gelatin