title: Modulation of the wettability of excipients by surfactant and its impacts on the disintegration and release of tablets.
abstract: OBJECTIVE
  To investigate the modulation of the wettability of excipients by different types of surfactants and its impacts on the disintegration of tablets and drug release.
  
  
  METHODS
  The critical micelle concentration (CMC) of surfactants, including sodium dodecyl sulfate (SDS), sodium dodecyl benzene sulfonate (SDBS), dodecyl trimethyl ammonium bromide (DTAB), cetyltrimethyl ammonium bromide (CTAB) and polysorbate (Tween-20 and Tween-80), was obtained using the platinum ring method. Contact angles of surfactant solutions on the excipient compacts and double-distilled water on the mixture of surfactant and the other excipient (magnesium stearate (MgSt) or sodium alginate (SA)) were measured by the sessile drop technique. Besides, surface free energy of excipients was calculated by the Owens method. Finally, the disintegration of tablets and in vitro dissolution testing were performed according to the method described in USP.
  
  
  CONCLUSIONS
  The wettability of excipients could be enhanced to different extent with low concentration of surfactant solutions and maintained stable basically after CMC. For MgSt (hydrophobic excipient), the shorter the hydrophobic chain (C12, including SDS and DTAB), the better the wettability with the addition of surfactant in the formulation, leading to the shorter disintegration time of tablets and higher drug release rate. In contrast, the wettability of SA (hydrophilic excipient) was reduced by adding surfactant, resulting in the longer disintegration time of tablets and lower release rate.
  
  
  CONCLUSIONS
  The modulation of the wetting of pharmaceutical excipients by surfactant had changed the disintegration time of tablets and drug release rate to a greater extent.
authors.affiliation: a School of Pharmacy , Shenyang Pharmaceutical University , Shenyang , Liaoning , China.
authors.forename: Baixue
authors.initials: B
authors.lastname: Yang
authors.affiliation: a School of Pharmacy , Shenyang Pharmaceutical University , Shenyang , Liaoning , China.
authors.forename: Lu
authors.initials: L
authors.lastname: Xu
authors.affiliation: a School of Pharmacy , Shenyang Pharmaceutical University , Shenyang , Liaoning , China.
authors.forename: Qiuxiao
authors.initials: Q
authors.lastname: Wang
authors.affiliation: a School of Pharmacy , Shenyang Pharmaceutical University , Shenyang , Liaoning , China.
authors.forename: Sanming
authors.initials: S
authors.lastname: Li
keywords: Contact angle; disintegration; drug release; excipient; surfactant; wettability