In the current study, the influence of type of plasticizer used with Eudragit® RS 30D on the drug release was investigated in solid dosage form extrusion/spheronization, and film coating. The drug pellets were coated for controlling drug release with Eudragit® RS 30D containing dibutyl phthalate and compared with dibutyl sebacate as an alternative plasticizer. To study the influence of pH of the dissolution medium on the drug release profile, capsules are tested for drug release profile at pH 1.2, 4.4, and 6.3. Additionally, the aging effect on the curing of Eudragit® RS 30D is evaluated by exposing the capsules dosage form to room temperature (25 °C ± 2 °C/60% ± 5% RH) for time 0, 3, 6, and 9 months, accelerated temperature (40 °C ± 2 °C/75% ± 5% RH) for time 0, 3, and 6 months, and intermediate temperature (30 °C ± 2 °C/65% ± 5% RH) for time 0, 6, and 9 months. The replacement of dibutyl phthalate, with dibutyl sebacate for polymer coating system in similar concentration is comparable with respect to plasticization effect. The coalescence of the polymer particles is not changed and requires no additional processing parameter control or additional curing time.