Spectrophotometric Determination of Aspirin, Phenacetin, and Caffeine in Mixtures

Determination of caffeine in APC tablets by densitometry on chemically bonded C18 reversed phase thin layers

“…The individual results were 1.26, 1.28, and 1.31 pglpl, with an average of 1.28 pglpl. An aliquot of the same solution prepared for TLC was analyzed by a standard spectrophotometric method [6] in which the aspirin is separated from caffeine and phenacetin by extraction at controlled pH, and the mixture of the latter two compounds is determined by measurement of absorbance at two wavelengths and simultaneous algebraic solving of the resulting equations. The result was 31.7 mg per tablet or 1.27 pg/pl, an adequate check of the TLC results.…”

Spectrofluorometric Determination of Acetylsalicylic Acid, Salicylamide, and Salicylic Acid as an Impurity in Pharmaceutical Preparations

“…The first type consists of simple placement of the suppository in a flask or beaker (11)(12)(13)(14)(15)). The second type utilizes an existing tablet dissolution apparatus that provides a wire mesh basket for holding the sample (16)(17)(18)(19)(20)(21)(22).…”

“…Many of these methods have never been examined for the effect of other constituents commonly found in recent preparations, such as other fluorescent salicylates and substances that absorb large amounts of exciting radiation. Direct UV methods for acetylsalicylic acid are based on prior separation from other components in the preparation (13)(14)(15).…”

Automated High‐pressure Liquid Chromatographic Analysis of Aspirin, Phenacetin, and Caffeine

“…A recent paper (11) reported conditions for the routine separation of common components of analgesic tablets. The determination of analgesics by HPLC overcomes many shortcomings of the previously reported methods (1)(2)(3)(4)(5)(6)(7)(8)(9).…”