title: In situ gelling formulation based on methylcellulose/pectin system for oral-sustained drug delivery to dysphagic patients.
abstract: BACKGROUND
  Oral-sustained release gel formulations with suitable rheological properties have been proposed as a means of improving the compliance of dysphagic and geriatric patients who have difficulties with handling and swallowing oral dosage forms.
  
  
  OBJECTIVE
  We have modified the rheological and release properties of thermally reversible methylcellulose solutions by admixture with pectin, the gelation of which is ion-responsive, with the aim of formulating an in situ gelling vehicle suitable for oral-sustained drug delivery.
  
  
  METHODS
  Gels formed by solutions containing methylcellulose (1.0-2.0%) and pectin (0.5-2.0%) were assessed for suitable gel strength, and in vitro and in vivo release of paracetamol.
  
  
  RESULTS
  Addition of 1.5% pectin to a 2.0% methylcellulose formulation containing 20% d-sorbitol and calcium ions in complexed form increased the gel strength and provided a formulation with a suitable viscosity for ease of swallowing by dysphagic patients. Gels formed in situ after oral administration of this formulation retained their integrity in the rat stomach for sufficient time for sustained release to be achieved. In vitro release of paracetamol from methylcellulose, pectin, and methylcellulose/pectin gels was diffusion-controlled. Plasma levels of paracetamol after oral administration to rats (gastric pH 2.6 and 5.5) of a solution including 2.0% methylcellulose/1.5% pectin showed improved sustained release compared with that from both 2.0% methylcellulose and 1.5% pectin solutions.
  
  
  CONCLUSIONS
  The addition of suitable concentrations of pectin to methylcellulose solutions produces in situ gelling formulations with suitable viscosity for administration to dysphagic patients and improved sustained release characteristics.
authors.affiliation: Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido, Japan. itou@hoku-iryo-u.ac.jp
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Itoh
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Hatakeyama
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Shimoyama
authors.forename: Shozo
authors.initials: S
authors.lastname: Miyazaki
authors.forename: Antony
authors.initials: A
authors.lastname: D'Emanuele
authors.forename: David
authors.initials: D
authors.lastname: Attwood
mesh_terms: D000082:Acetaminophen / Q000008:administration & dosage / Q000493:pharmacokinetics; D000284:Administration, Oral; D000818:Animals; D003680:Deglutition Disorders / Q000188:drug therapy*; D003692:Delayed-Action Preparations / Q000008:administration & dosage* / Q000493:pharmacokinetics; D004339:Drug Compounding / Q000379:methods; D016503:Drug Delivery Systems / Q000379:methods*; D005753:Gastric Mucosa / Q000378:metabolism; D005782:Gels; D006801:Humans; D008297:Male; D008747:Methylcellulose; D010368:Pectins; D051381:Rats; D017208:Rats, Wistar; D012212:Rheology; D014783:Viscosity
chemical_list: D003692:Delayed-Action Preparations; D005782:Gels; D000082:Acetaminophen; D010368:Pectins; D008747:Methylcellulose