Stability of Amoxicillin Trihydrate Oral Suspension in Clear Plastic Unit Dose Syringes

Abstract The stability of amoxicillin trihydrate oral suspension stored in clear plastic oral syringes was studied. Commercially available amoxicillin trihydrate powder for oral suspension was reconstituted according to manufacturer's instructions and drawn into 5-mL clear polypropylene plastic oral syringes. The syringes were divided into groups and stored at 25, 40, 60 or 80°C. Powder from two additional lots was similarly reconstituted, packaged and stored at 80°C only to assess interlot variability. Immediately after reconstitution and at specified times during storage, three syringes at each storage temperature were removed and their contents analyzed for amoxicillin trihydrate concentration by a spectrophotometric assay. Samples stored at room temperature retained at least 90% of the initial amoxicillin concentration for at least 78 days. Samples stored at heated temperatures (40, 60, and 80°C) exhibited a first-order degradation process, with the concentration of amoxicillin decreasing to less than 90% of the initial concentration within 240, 7 and 1.5 hours, respectively. Reconstituted amoxicillin trihydrate powder for oral suspension is stable for 75 days when stored at room, refrigerated, or frozen temperature in the clear plastic oral syringes studied. The expiration dates recommended by the manufacturer for amoxicillin trihydrate suspension stored in its original container can also be used for reconstituted suspension stored in these clear plastic syringes.