Eudragit as the Material for the Production of Rifampicin and Isoniazid Microparticles


Rifampicin and isoniazid are two of the first-line drugs used to treat tuberculosis (TB). Rifampicin is sensitive to light, heat and moisture, and is also known to have poor solubility which affects the absorption of the drug in the gastrointestinal tract. This study was conducted to investigate the effects of different types of Eudragit® in the formulation of microparticles of rifampicin and isoniazid. Two types of Eudragit were used which are Eudragit RL-PO and Eudragit RS-PO. The particle size of rifampicin microparticles for Eudragit RL-PO and Eudragit RS-PO were recorded at 44 μm and 64 μm, respectively. Isoniazid microparticles were found to have volume mean diameters of 63 μm and 54 μm for formulations incorporated with Eudragit RL-PO and Eudragit RS-PO, respectively. Eudragit RL-PO formulated rifampicin microparticles encapsulated 80.8% and 23.3% for those formulated with Eudragit RS-PO. Isoniazid microparticles recorded an encapsulation efficiency of 98.7% and 61.9% in formulations using Eudragit RL-PO and Eudragit RS-PO correspondingly. The formulations retained some of the functional groups, but changes were also observed. Scanning electron microscope (SEM) shows consistently spherical and porous microparticles with rough surfaces. Dissolution studies indicate that isoniazid was released by Quasi-Fickian mechanism while rifampicin was released by non-Fickian mechanism.