Effects of Citric Acid and Sodium Alginate on the Stability and Dissolution of Clarithromycin Extended-Release Tablet

The pharmacokinetics of clarithromycin (CLR) conventional tablets (T1/2: 5-7 h) demand 2 or 3 doses per day, which is inconvenient for patients. Therefore, a sustained-release CLR tablet is necessary. Based on Klacid MR tablets (AbbVie) composed of citric acid and sodium alginate (Na-ALG), we developed a 24-hour extended-release CLR tablet. Although citric acid had a significant effect on the CLR release profile, the incompatibility of citric acid and CLR was reported (via FT-IR and stability study). Based on the function of Na-ALG in controlling the release and reducing the incompatibility of citric acid and CLR, a process (CLR and citric acid were granulated separately) was proposed. The final tablet formulation showed 1-month stability and dissolution similarity to standard tablets in pH 6.8 medium (f2 > 50).