Study of the Stability of Amoxicillin Trihydrate Oral Suspension in Different Storage Temperatures by HPLC

Abstract

Oral suspensions of antibiotics are mainly available as dry powders for reconstitution. Many reconstituted antibiotic suspensions are kept refrigerated in order to get the optimal benefit from the drug. However, many patients do not keep to the specified storage conditions for different reasons like absence of a refrigerator and irregular power supply that may result in various degrees of degradation of the product. Scientists are therefore challenged on how to counsel patients when there is no refrigeration or erratic power supply for refrigeration. The aim of this study is to investigate the stability of reconstituted amoxicillin suspension in absence of refrigeration. Amoxicillin suspension samples obtained from Pharmaland Pharmaceutical were reconstituted and stored in three different storage conditions including different temperatures: 8 °C, 30°C and 40°C over a period of fourteen days. Samples from the suspension were assayed using a validated HPLC method. Percentage concentrations of amoxicillin were over 90% up to the seventh day, degradation was extensive by the 14th day with amoxicillin concentration falling below 80% (67.4%, 72.4% at 40 °C). It is recommended that reconstituted suspension which is not properly refrigerated should be discarded after seven days.