title: Equipment and method for in vitro release measurements on topical dosage forms.
abstract: BACKGROUND
  In countries where research budgets are meager as Argentina, the tendency to innovation and improvements in the designs prototypes "made in Argentina" marks a growing trend adopted by researchers. This article presents a diffusion cell of original design, for release studies of Active Pharmaceutical Ingredient (API) from classical topical dosage forms, also includes the methodology for its optimization and validation. The objective was to evaluate and validate a system designed and to compare it to the Franz cells system.
  
  
  METHODS
  Parameters, reproducibility and robustness were performed included factors as, stirring conditions, membrane stabilization treatment and temperature variation. Release and retention on membrane assay were performed using two different API and formulations.
  
  
  RESULTS
  The method is reproducible and robust for the parameters tested. Release assays show that no significative difference with the Franz Cells system. Our system allows the simultaneous measurement of different parameters, representing an innovation on these methodologies. The LMC was used for assays of in vitro retention on membrane and the values obtained were reproducible and coincident whit values obtained for other authors.
  
  
  CONCLUSIONS
  The system designed and the methodology employed, are acceptable for in vitro release studies. The device and method has the characteristics required.
authors.affiliation: Facultad de Bioquímica, Química y Farmacia, Cátedra de Tecnología Farmacéutica II, Instituto de Farmacia, CONICET, Universidad Nacional Tucumán , Tucuman , Argentina .
authors.forename: Maria Eugenia
authors.initials: ME
authors.lastname: Sesto Cabral
authors.forename: Alberto Nicolas
authors.initials: AN
authors.lastname: Ramos
authors.forename: Carla Agostina
authors.initials: CA
authors.lastname: Cabrera
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Valdez
authors.forename: Silvia Nelina
authors.initials: SN
authors.lastname: González
mesh_terms: D000287:Administration, Topical; D002626:Chemistry, Pharmaceutical / Q000295:instrumentation* / Q000379:methods; D004058:Diffusion; D065546:Drug Liberation; D004791:Enzyme Inhibitors / Q000008:administration & dosage / Q000737:chemistry; D004867:Equipment Design; D008567:Membranes, Artificial; D009824:Ointments / Q000737:chemistry; D026023:Permethrin / Q000008:administration & dosage / Q000737:chemistry; D004364:Pharmaceutical Preparations / Q000008:administration & dosage* / Q000737:chemistry; D015203:Reproducibility of Results
chemical_list: D004791:Enzyme Inhibitors; D008567:Membranes, Artificial; D009824:Ointments; D004364:Pharmaceutical Preparations; D026023:Permethrin
keywords: In vitro vertical diffusion cell; residence time; retention on membrane assay