Individual and Combined Effect of Eudragit® RS 100 and Eudragit® RL 100 on Sustained Release Characteristics of Ropinirole HCl-loaded Microparticles

Ropinirole HCl is a non-ergoline dopamine agonist which is recommended for the treatment of both Parkinson’s disease and Restless Legs Syndrome (RLS). Its half-life is about 6 hours and it is metabolized in the liver primarily by CYP1A2. Its metabolites are water-soluble and rapidly excreted from the body in urine. However, its oral bioavailability is low. Therefore, this current project aimed to produce and evaluate sustained release ropinirole microparticles coated with Eudragit® RS 100 and RL 100 by varying polymer types and concentrations. Ropinirole microparticles were prepared by oil in oil emulsion solvent evaporation technique. Emulsifier concentration was constantly set at 2% with a stirring speed of 500 pm. FTIR analysis of microparticles, drugs, and polymers was carried out. Analysis of compatibility, particle size, encapsulation effciency, yield, flow properties, and release profile were also performed. The optical microscope showed the spherical microparticles with better flow properties and encapsulation. Ropinirole FTIR analysis produced sharp characteristic bands of C=O stretching at 1699 cm-1, bending of CH3 at 1457 cm-1, C=C aromatic stretching at 1521 cm-1 and 1541 cm-1, and C-H aromatic bending at 765 cm-1. Eudragit® RS 100 and Eudragit® RL 100 showed a major peak with C=O stretching at 1716 cm-1. Within 8 hours, the drug release was in the range of 47.48-98.78%. Increasing the polymer concentration increased particle size, entrapment efficiency, and sustained drug release. Eudragit® RS 100 alone achieved a better sustained release than in combination with Eudragit® RL 100 or Eudragit® RL 100 alone.