Development and Validation of an HPTLC‐Densitometry Method for Assay of Caffeine and Acetaminophen in Multicomponent Extra Strength Analgesic Tablets

Abstract

A quantitative method using silica gel HPTLC plates with fluorescent indicator, automated sample application, and UV absorption densitometry has been developed for the determination of caffeine and acetaminophen in pharmaceutical preparations. Multicomponent analgesic tablets containing caffeine, acetaminophen, and acetylsalicylic acid as the active ingredients were analyzed to test the applicability of the new method. Precision for the caffeine analysis was evaluated by replicate analysis of samples and accuracy by analysis of two spiked blank samples containing inactive ingredients in common with the multicomponent analgesic tablets. The amount of caffeine in the tablets analyzed ranged from 96 to 115% of the label value. Precision was 1.19% relative standard deviation, and the errors from the two spiked blank analyses averaged 1.90% compared with fortification levels. The limit of detection was 0.200 µg of caffeine. Precision for acetaminophen analysis was evaluated also by replicate analysis of samples, and accuracy was measured by standard addition analysis. The amount of acetaminophen in the tablets analyzed ranged from 97 to 110% of the label value. Precision ranged from 0.949 to 7.56% difference for duplicate samples. For the standard addition analysis, the error was 1.03% compared with fortification levels. The limit of detection was 0.0800 µg of acetaminophen.