Comparative Hydrolysis Study of Acetylsalicylic Acid and Copper (II)-Acetylsalicylate by RP-HPLC Method

Abstract

The hydrolysis of acetylsalicylic acid (ASA) and copper (II)-acetylsalicylate (CAS) was investigated by using a validated RP-HPLC method. Acetylsalicylic acid was hydrolyzed to (SA), where as CAS was hydrolyzed to ASA, SA, copper salicylate (CS), copper acetate and acetic acid. Comparison of hydrolysis was carried out by monitoring the concentration of SA, one of common hydrolysis product. The hydrolysis study was done in phosphate buffer solution in pH range from 3- 11. The study was carried out at constant temperature to evaluate the effect of pH on both drugs. It was found that the hydrolysis rate of both drugs was same at pH value ranging from 3-11 as calculated from the Kapp and K values. However, there is a slight difference in the degradation of ASA and CAS as revealed from F-test. Results have indicated that CAS first hydrolyzes to acetylsalicylic acid which further hydrolyzes to SA, therefore availability of acetylsalicylic acid is increased.