Abstract

In this study, development and validation of a high performance liquid chromatographic method without an internal standard, for simultaneous determination of acetaminophen and caffeine in tablets was reported. This analysis was carried using a LaChrom Elite chromatograph and diode array detector. The separation was carried out in a RP column (C18), at room temperature, 275 nm detection, 1.5 ml/min flow, and water-methanol-acetic acid (69:28:3, v/v/v) as the mobile phase. No chromatographic interference was found. The linearity of the method proposed was assessed in the range 60-140 µg/ml and 7.9-18 µg/ml for acetaminophen and caffeine, respectively, being linear relationships in these ranges and validated the correlation coefficient (r2=0.9989 acetaminophen; r2=0.9982 caffeine), the slope and the intercept. Precision, measured as repeatability and as intermediate precision, and assessed through the coefficient of variation was less than 2.0% for both analytes. Recovery percentages were 99.53% and 99.12% for acetaminophen and caffeine, respectively. Reproducibility of this method was proven through an interlaboratory assay. Elimination of the internal standard for this method does not affect the quantification of the active principles significantly in finished product batches against the method using such internal standard. The outcome of this assay proves that proposed methodology is simple, fast, precise, accurate, and it may be confidently used for the determination of acetaminophen and caffeine in tablets.