Compatibility and Chemical Stability Study of Bilayer Tablets Pharmaceutical Dosage Form of Aspirin/Clopidogrel as Eudragit L100 Polymer Main Excipient 

Due to the multiple diseases in the same patients, and the multiple medications they were taking, it was necessary to formulate medications containing two or more pharmaceutical substances to reduce the patient’s dosage and, as a result, reduce side effects. In this study aspirin and clopidogrel were formulated together in a pharmaceutical dosage form that ensures the chemical and physical stability. By wet granulation method as a first layer for clopidogrel as eduragit L100 as a polymer, which is considered an inner granule that achieves acceptable properties. The study formulates bilayer tablets containing aspirin and clopidogrel, using Eudragit L100-coated clopidogrel granules to minimize direct contact between the two drugs. Tablets were produced by wet granulation and evaluated for physical quality, dissolution, disintegration, and accelerated stability (40℃/60% RH, three months) for the first study, and another condition (50℃/75% RH, three months). Results show acceptable tablet hardness, friability, disintegration, and 94% - 99% drug content after accelerated testing, indicating chemical compatibility. The authors conclude that the bilayer design with Eudragit L100 improves stability of the aspirin-clopidogrel combination.