pH‐Sensitive methacrylic acid–methyl methacrylate copolymer Eudragit L100 and dimethylaminoethyl methacrylate, butyl methacrylate, and methyl methacrylate tri‐copolymer Eudragit E100
Abstract
Poly (methyl methacrylate) derivatives such as Eudragit are polymers 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 physico-chemical parameters such as pH, polymer concentration, salinity, buffer concentration and incubation time on the solubilization and precipitation of these polymers were studied. 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 pre-cited parameters could not be dissociated and exert a synergic action on the solubilization and precipitation of both polymers. 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 did not behave as classic polyelectrolytes since solubilization and precipitation domains were not affected by ionic strength. Titration curves revealed two equivalences that helped estimating carboxylic content of Eudragit L100 (6 mmol/g) and
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