Acetylsalicylic Acid and Glycerol: Precision Evaluation

Method precision was tested by preparing model solutions corresponding to sample solution of dosage 150 mg ASA and 40 mg GLY (active substances and excipients)—sample solution preparation was described in “Methods” section. Solutions were spiked with salicylic acid at the concentrations which were equivalent to 0.005%, 0.05% and 0.30% with respect to acetylsalicylic acid content in a sample. Three replicates were prepared for each concentration level. The analysis was performed in duplicate by Analyst 1 at the same day and using the same HPLC system to evaluate intra-day precision. For inter-day precision Analyst 2 performed analysis on a different day, using different HPLC system. %Found of salicylic acid, standard deviations in groups of results, %RSD as well as intra-day and inter-day variance were calculated.