H-point standard additions method for simultaneous determination of paracetamol and phenylephrine in pharmaceutical preparations

Abstract

The development of H-Point Standard Additions Method (HPSAM) has been applied to resolve the corresponding overlapping spectra of paracetamol (PAR)  and phenylephrine (PHEPH) by Ultraviolet–visible spectrophotometry. HPSAM is based on the  coupling of PAR and PHEPH with diazotized of 1-aminopyrene reagent to form relatively stable water soluble colored azo compounds. The results of reactions show that maximum absorptions of PAR and PHEPH azo compounds are (490 nm and 420nm) respectively. The Individual calibration shows that the linear range was (10-90) and (5 -80) μg.ml-1 for PAR and PHEPH, respectively.The relative standard deviations RSD for the simultaneous determination of PAR and PHEPH by H-point standard addition method were 0.553 and 0.227, respectively. The results show that the proposed method is suitable for the simultaneous determination of PAR and PHEPHE in different pharmaceutical preparations.