title: First derivative spectrophotometric and high performance liquid chromatographic simultaneous determination of benzoic and salicylic acids in pharmaceutical preparations.
abstract: Two methods are presented for the simultaneous determination of benzoic and salicylic acids in pharmaceutical preparations using first (1D) derivative spectrophotometry and high-performance liquid chromatography. Benzoic and salicylic acids were determined by measurement of first derivative amplitude at the zero crossing points 283 and 310 nm respectively. Methanolic solutions obeyed Beer's law in the concentration range of 20-60 and 10-30 microg/ml for benzoic and salicylic acids respectively. The HPLC method depends upon using a Vydac reversed-phase column at ambient temperature with a mobile phase consisting of 20:80 (ACN:H2O) at a flow rate 0.5 ml min(-1) Quantitation was achieved with UV detection of 230 nm at 0 min and 204 nm at 4 min based on peak area. For the two methods the regression line equations were derived with correlation coefficient better than 0.995. The two methods were successfully applied to the simultaneous determination of benzoic and salicylic acids in laboratory-prepared mixtures and in creams with good accuracy and precision. No significant differences were found between the results obtained both by the HPLC and derivative procedures.
authors.affiliation: Department of Pharmaceutics, Faculty of Pharmacy, University of Lagos, Nigeria.
authors.forename: B O
authors.initials: BO
authors.lastname: Silva
mesh_terms: D019817:Benzoic Acid / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D012044:Regression Analysis; D020156:Salicylic Acid / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D013997:Time Factors
chemical_list: D004364:Pharmaceutical Preparations; D019817:Benzoic Acid; D020156:Salicylic Acid