*3.6. pH and Osmolarity*

Regarding the requirements for nasal formulations, the pH (5.5–6.59) and osmolarity (280 mOsm/kg) were adjusted to the physiological values in the optimized rivastigmine-loaded NLC formulations [80].

The pH was measured at room temperature using a BASIS 20 calibrated digital pH meter (Crison Instruments, Spain) and the osmolarity was assessed using a Type 6 osmometer (Löser Messtechnik, Berlin-Spandau, Germany).
