**2. Materials**

Rivastigmine base (liquid) of 99.9% purity was kindly provided by Novartis (Basel, Switzerland). Precirol® ATO 5 (glyceryl distearate/glyceryl palmitostearate) was donated from Gattefossé (Lyon, France) and Phospholipon® 90G (phosphatidylcholine, hydrogenated) was a gift from Lipoid (Ludwigshafen am Rhein, Germany), alpha-tocopherol acetate (vitamin E), polysorbate 80 (Tween® 80) and benzalkonium chloride were purchased from Acef (Piacenza, Italy) and Acofarma (Barcelona, Spain), respectively. The water used in all experiments was purified, obtained from a Milli®Q Plus, Millipore® (Darmstadt, Germany). For the mobile phase, acetonitrile <sup>≥</sup>99.9% purity was purchased

from Fisher Chemical-Thermo Fisher Scientific (Loughborough, UK); disodium phosphate was purchased from Sigma Aldrich (Lisbon, Portugal); monosodium phosphate from Merck (Darmstadt, Germany); and sodium chloride, potassium chloride and calcium chloride were purchased from Acofarma (Barcelona, Spain).
