Stability of aspirin in 2% aspirin ointment was studied using micellar electrokinetic chromatography (MEKC) which is one of the methods of capillary electrophoresis.
The preparation of a sample is very simple, only to disperse a few milligrams of ointment into a buffer by ultrasonication.
A half life of aspirin in 2% washable aspirin ointment at 30° was found to be 51.7 days determined by MEKC, which corresponds to the value obtained by HPLC.
