Abstract
A new spectrophotometric method was developed for the simultaneous analysis of a ternary mixture containing paracetamol (PAR), ibuprofen (IBU) and caffeine (CAF) without prior separation. H-point standard addition method (HPSAM) was used for the first time in the analysis of a component (IBU) in a ternary mixture (paracetamol, ibuprofen and caffeine). In contrast, PAR and CAF determined using double divisor ratio spectra derivative method. This method is based on the use of derivative of the ratio spectrum obtained by dividing the absorption spectrum of the ternary mixture by a standard spectrum of a mixture of two of the three compounds in the title mixture. The concentrations of PAR and CAF compounds in their mixture are determined by using their respective standard addition graphs which are obtained by measuring the amplitude at either the maximum or minimum wavelengths selected. The mathematical explanation of the procedure is illustrated. It was shown that at wavelengths 226 and 260 nm, the coordinate of H-point is only dependent on the concentration of IBU without any interference by PAR and CAF. This method was successfully applied for the analysis of Novafen capsule, with no interference from excipients as indicated by the recovery study results. The proposed method is simple and rapid and can be easily used in the quality control of drugs as an alternative analysis tools.