SIMULTANEOUS ANALYSIS OF A THREE COMPONENT MIXTURE BY VIERODT’S SIMULTANEOUS EQUATION METHOD

A simple, rapid, sensitive and economical UV spectrophotometric method was developed and validated for the simultaneous estimation of aspirin, caffeine, and orphenadrine citrate by Vierodt's method in combined tablet dosage form and using mixture of 0.1 N HCl: ethanol (1:1) as solvent. The method employs designing and solving of simultaneous equations using 3 wavelengths, namely 226 nm, 272 nm, and 210 nm. Beer's law was obeyed in the concentration range of 3-18 μg/mL for aspirin and 0.5-12 μg/mL for both caffeine and orphenadrine citrate with r2 value of 0.993, 0.991, and 0.991 respectively. Accuracy was determined by recovery studies and showed percent recovery ranging from 99.78-100% for aspirin, 96.10-100.92% for caffeine and 100.53-102.5% for orphenadrine citrate. The developed method can be used in QC laboratory for routine analysis to ensure the identity, purity, and performance of the drug product.