title: An alternative in situ gel-formulation of levofloxacin eye drops for prolong ocular retention.
abstract: BACKGROUND
  Delivering drugs to ocular region is a challenging task. Eye physiological barriers lead to relatively less therapeutic and bioavailability effect by the conventional eye drops. This may be overcome by the use of in situ gel delivery system.
  
  
  OBJECTIVE
  The objective of our work was to formulate an ocular delivery system of levofloxacin, based on the concept of ion (sodium alginate) and pH (chitosan) activated in situ gelation concept. Due to its elastic properties, in situ gels resist the ocular drainage of drug leading to longer contact times with ocular surface.
  
  
  METHODS
  The formulation was evaluated for physicochemical characteristics, in vitro drug release. Ocular retention studies were carried out by Gamma scintigraphy. Time activity curve was plotted between marketed formulation and developed formulation for comparing drug drainage from the eye with time. Ocular tolerance test was performed by handheld infra-red camera.
  
  
  CONCLUSIONS
  The formulations showed a first-order release pattern over 12 h. Both in vitro release studies and in vivo gamma scintigraphy precorneal retention studies indicated better therapeutic efficacy compared with standard eye drops.
  
  
  CONCLUSIONS
  The results demonstrated that the developed in situ gel of levofloxacin is nonirritant, has prolonged action and is a better option in terms of retention, ocular bioavailability and patient compliance when compared with plain eye drops formulation.
authors.affiliation: Department of Pharmacy and Pharmaceutical Sciences, University of Toledo, Toledo, OH 43614, USA.
authors.forename: Himanshu
authors.initials: H
authors.lastname: Gupta
authors.affiliation: Department of Pharmaceutics, Faculty of Pharmacy, Jamia Hamdard, New Delhi, India.
authors.forename: M
authors.initials: M
authors.lastname: Aqil
authors.affiliation: Department of Pharmaceutics, Faculty of Pharmacy, Jamia Hamdard, New Delhi, India.
authors.forename: R K
authors.initials: RK
authors.lastname: Khar
authors.affiliation: Department of Pharmaceutics, Faculty of Pharmacy, Jamia Hamdard, New Delhi, India.
authors.forename: Asgar
authors.initials: A
authors.lastname: Ali
authors.affiliation: Department of Nuclear Medicine, Institute of Nuclear Medicine and Allied Sciences, Ministry of Defence, New Delhi, India.
authors.forename: Aseem
authors.initials: A
authors.lastname: Bhatnagar
authors.affiliation: Department of Nuclear Medicine, Institute of Nuclear Medicine and Allied Sciences, Ministry of Defence, New Delhi, India.
authors.forename: Gaurav
authors.initials: G
authors.lastname: Mittal
keywords: Chitosan; gamma scintigraphy; in situ gel; levofloxacin; ocular tolerance; radiolabelling