|Molecular Weight||180.159 g/mol|
Excedrin is over-the-counter pain reliever containing acetaminophen, caffeine and aspirin as active ingredients of this drug composition. Acetaminophen (paracetamol) is used as analgesic and pain reliever. It is a neutral compound with low hydrophobicity. Aspirin or acetylsalicylic acid is used as analgesic and anti-inflammatory component of many OTC compositions. It is weakly acidic and slightly hydrophobic compound. Caffeine is xanthine alkaloid which is psychoactive stimulant drug. All four compounds are separated on mixed-mode Primesep 100 HPLC column with acetonitrile/water/TFA mobile phase. In this HPLC application compounds are retained by reversed phase mechanism. This HPLC method is short and robust.
Application Notes: Acetametaphin, aspirin, and caffeine tablets contain not less than 90 percent and not more than 110 percent of the labeled amounts if acetametaphin, asprin, and caffeine according the USP methods. USP HPLC method for separation of acetaminophen, aspirin and caffeine was developed on Legacy L1 column according to US Pharmacopeia methodology. L1 classification is assigned to reversed-phase HPLC column contains C18 ligands. Support for the material is a spherical silica gel with particles size 3-10 um and pore size of 100-120A. Resolution between critical pairs corresponds to rules and specifications of USP.
Application Columns: Legacy L1 C18 HPLC column
Application compounds: Acetaminophen, Aspirin, Caffeine, benzoic acid, and salicylic acid
Mobile phase: MeOH/H2O/AcOH 28/69/3
Detection technique: UV
Reference: USP30: NF35
|Column||Legacy L1, 4.6x300 mm, 5 µm, 100A|
|Mobile Phase||MeCN - 25%|
|Buffer||AmFm pH 3.0 20 mM - 75%|
|Flow Rate||1.0 ml/min|
|Detection||UV, 250 nm|
|Class of Compounds||Drug, Acid, Hydrophobic, Ionizable|
|Analyzing Compounds||Aspirin (Acetylsalicylic acid (ASA))|