title: The in vitro release of some antimuscarinic drugs from monoolein/water lyotropic liquid crystalline gels.
abstract: OBJECTIVE
  To investigate the potential use of a monoolein/water lyotropic liquid crystalline gel for the vaginal delivery of the antimuscarinic drugs, propantheline bromide and oxybutynin hydrochloride to treat urinary incontinence, using Myverol 18-99 as a commercially available grade of monoolein.
  
  
  METHODS
  The influence of propantheline bromide and oxybutynin hydrochloride on the phase structure of Myverol 18-99/water gels was investigated using polarising microscopy. The in-vitro release of the antimuscarinic drugs from Myverol 18-99/water gels was determined and the release pattern interpreted with the aid of results from swelling studies and partition coefficient determinations.
  
  
  RESULTS
  Myverol 18-99 forms gels with lyotropic liquid crystalline structures in the presence of water. The addition of propantheline bromide and oxybutynin hydrochloride promoted the formation of gels with a lamellar phase structure. The gels absorbed water at a rate inversely proportional to their initial water content until they reached an equilibrium water content of approximately 40% w/w whilst maintaining their physical integrity. The release of the antimuscarinic drugs was sustained over a period of approximately 18 hours and followed square root of time kinetics indicating that the rate of release was diffusion controlled.
  
  
  CONCLUSIONS
  The in-vitro release behaviour of Myverol 18-99/water gels suggested that they are suitable carriers to deliver propantheline bromide or oxybutynin hydrochloride. The results of swelling studies indicated that a confined area, such as the vaginal cavity, would be a suitable site of administration.
authors.affiliation: Department of Pharmacy, University of Manchester, England.
authors.forename: P B
authors.initials: PB
authors.lastname: Geraghty
authors.forename: D
authors.initials: D
authors.lastname: Attwood
authors.forename: J H
authors.initials: JH
authors.lastname: Collett
authors.forename: Y
authors.initials: Y
authors.lastname: Dandiker
mesh_terms: D004337:Drug Carriers; D005782:Gels; D005989:Glycerides; D008853:Microscopy; D018727:Muscarinic Antagonists / Q000493:pharmacokinetics*; D014867:Water
chemical_list: D004337:Drug Carriers; D005782:Gels; D005989:Glycerides; D018727:Muscarinic Antagonists; D014867:Water; C005953:monoolein