title: In vitro evaluation of some parameters involved in mucoadhesion of aqueous polymeric dispersions.
abstract: BACKGROUND
  The mucoadhesive formulations are constantly developing due to their relevance in the drug delivery to various districts of the organism.
  
  
  OBJECTIVE
  The purpose of this study was to find a direct link between physicochemical properties of the polymers and their adhesive ability in order to offer guidelines for the development of mucoadhesive semisolid formulations.
  
  
  METHODS
  Twelve polymers were dispersed in water and characterized with regard to their mucoadhesiveness, apparent viscosity, contact angle on solid surface, and hydrodynamic diameter of their molecules. The adhesive properties were related to the other measured parameters.
  
  
  CONCLUSIONS
  The data seem to indicate the existence of an optimal value of viscosity, around 5-6 Pa s, to obtain the highest mucoadhesiveness of the polymeric dispersions. Regarding the molecular sizes, the best mucoadhesive performances seem to be given from polymers with a hydrodynamic diameter lower than 350-400 nm. In any case, the ability to wet the surface by the polymeric dispersion seems to play an essential role in bioadhesion process, capable of strongly limiting the phenomenon.
  
  
  CONCLUSIONS
  Performing simple in vitro measurements, it seems possible to identify the best polymeric concentration to obtain a semisolid formulation with good mucoadhesive properties.
authors: a Department of Pharmacy , University of Pisa , Pisa , Italy.
authors: Susi
authors: S
authors: Burgalassi
authors: a Department of Pharmacy , University of Pisa , Pisa , Italy.
authors: Daniela
authors: D
authors: Monti
authors: a Department of Pharmacy , University of Pisa , Pisa , Italy.
authors: Silvia
authors: S
authors: Tampucci
authors: a Department of Pharmacy , University of Pisa , Pisa , Italy.
authors: Patrizia
authors: P
authors: Chetoni
keywords: Bioadhesion; molecular size; viscosity; wettability