Poly (methyl methacrylate) derivatives such as Eudragit are largely used for drug encapsulation and in controlled oral drug delivery. With special focusing on those applications, solubilization and precipitation conditions of two pH-sensitive Eudragit polymers, namely, L100 and E100, were investigated via systematic studies. Effects of various physicochemical parameters such as pH, polymer concentration, salinity, buffer concentration, and incubation time on the solubilization and precipitation of these polymers were investigated. In addition, pH titration of both polymers was reported. Considering both macroscopic and quantitative aspects such as the final mean particle size, size distribution, morphology, and the zeta potential, it was established that the different precited parameters could not be dissociated and exert a synergic action on the solubilization and precipitation of both polymers. Titration curves revealed two equivalences that helped estimating carboxylic content of Eudragit L100 (6 mmol/g) and ammonium content of Eudragit E100 (4 mmol/g). In this study, the solubilization and the precipitation domains were for the first time clearly established by considering the above-mentioned parameters. Moreover, it was found that Eudragit L100 and E100 cannot be considered as classic polyelectrolytes; in fact, solubilization and precipitation domains were not affected by ionic strength. electrical field. 3,7 Due to their unique properties, materials prepared using these polymers are known as smart materials. Stimuli-responsive polymers are generally classified in two main categories depending on their response to external stimuli: (a) Physical stimuli, such as temperature, light, electrical field, or magnetic field, which cause intermolecular interactions, and (b) chemical stimuli, which change the molecular structure of the polymer by the addition of chemical agents or by changing the physicochemical properties of the used solvent such as pH and ionic strength. 8 Moreover, polymers can be sensitive to more than one stimulus, which makes them dual-stimuli-responsive or multi-stimuliresponsive. These sensitive polymers are used in several applications such as drug delivery and membrane coating, 7 as artificial organs, sensor materials, 9 etc.