Stability of amoxycillin and potassium clavulanate in co-amoxiclav oral suspension.

A study was carried out using high performance liquid chromatography (HPLC) to determine the chemical stability of amoxycillin and potassium clavulanate in 250/62 co-amoxyclav oral suspension (Augmentin), stored at room temperature (RT, 20 degrees C) and 8 degrees C over a period of 11 days. The suspension was judged to be acceptable if its components maintained at least 90% of their label concentrations. During the test period, the amoxycillin component was found to be more stable than the clavulanate. Amoxycillin was stable for 7 days at both temperatures. Potassium clavulanate maintained at least 90% of its initial concentration for 7 days at 8 degrees C but showed more than 40% degradation in the same time period at RT. For potassium clavulate the shelf-life, or time taken for the original concentration to drop to 90% of its value (t90) at RT was found to be 2 days.