Development of Eudragit RS 100 Microparticles Loaded with Ropinirole: Optimization and In Vitro Evaluation Studies

The current study aimed to develop novel pH independent microparticles loaded with ropinirole (ROP) for sustained drug release. Eudragit RS 100 was used as release retardant and microparticles were fabricated by oil-in-oil emulsion solvent evaporation method. A three-factor three-level Box-Behnken design using Design-Expert software was employed to optimize formulation variables. Ropinirole loaded microparticles were evaluated with respect to morphology, particle size, encapsulation efficiency, and in vitro release profile. Optical microscopy and SEM micrographs indicated spherical shape with smooth surface and well-defined boundary. The particle size was in the range of 98.86 to 236.29 μm, being significantly increased with increasing polymer concentration. Higher polymer load also increased the thickness of internal polymer network, which led to reduced drug loss and higher entrapment efficiency (89%). The cumulative in vitro release was found to be in the range of 54.96 to 99.36% during the release studies (12 h) following zero order release kinetics and non-Fickian diffusion pattern. The developed microparticles have the potential to sustain the release of ropinirole, which may lead to a reduction in its adverse effects and improved management of Parkinson's disease.