title: Towards a rational basis for selection of excipients: Excipient Efficiency for controlled release.
abstract: There are many factors influencing the drug release behaviour from a pharmaceutical formulation as the particle size of the drug and excipient, porosity of the system or geometrical phase transitions of the components. Therefore, the choice of the adequate excipient to achieve a specific drug release profile is mainly based on the experience and the trial and error method. Taking into account the directives towards the application of the "Quality by Design" approach, in this study the Excipient Efficiency (EE), a parameter able to quantify the capability of an excipient to control the drug release, has been developed. EE was initially calculated dividing the total porosity of the system by its diffusional release rate constant. The influence of several factors on this parameter has been evaluated. As a result, the final parameter has been corrected based on the drug solubility and the excipient particle size. EE provides a rational basis for identifying the most adequate excipients for a concrete formulation.
authors.affiliation: Department of Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Casas
authors.affiliation: Department of Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain. Electronic address: aguilardeleyva@us.es.
authors.forename: Ángela
authors.initials: Á
authors.lastname: Aguilar-de-Leyva
authors.affiliation: Department of Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, University of Seville, 41012 Seville, Spain.
authors.forename: Isidoro
authors.initials: I
authors.lastname: Caraballo
mesh_terms: D002626:Chemistry, Pharmaceutical; D003692:Delayed-Action Preparations / Q000737:chemistry*; D065546:Drug Liberation; D005079:Excipients / Q000737:chemistry*; D008956:Models, Chemical; D010316:Particle Size; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D016062:Porosity; D012995:Solubility; D013607:Tablets / Q000737:chemistry*
chemical_list: D003692:Delayed-Action Preparations; D005079:Excipients; D004364:Pharmaceutical Preparations; D013607:Tablets
keywords: Controlled drug release; Critical points; Excipient Efficiency; Particle size; Porosity; solubility