Rapid and Simultaneous Determination of Acetylsalicylic Acid, Paracetamol, and Their Degradation and Toxic Impurity Productsby HPLC in Pharmaceutical Dosage Forms

Aims: Determinations of drug impurity and drug degradation products are very important from both pharmacological and toxicological perspectives. Establishment of monitoring methods for impurities and degradation products during pharmaceutical development is necessary because of their potential toxicity. The aim of this study was to develop a rapid and simultaneous determination method for paracetamol and acetylsalicylic acid (ACA) and their degradation and toxic impurity products by high performance liquid chromatography (HPLC) in pharmaceutical dosage forms.Materials and Methods: A reverse phase (RP)-HPLC method for the simultaneous analysis of paracetamol,ACA, and ascorbic acid and their degradation and impurity products such as salicylic acid (SA) and p-chloroacetanilide was developed and applied to the determination of these compounds in commercial dosage forms. These compounds were well separated on a Bondapak C18 reverse phase column using a mobile phaseconsisting of a mixture of methanol: water (35:65; v/v) adjusted to pH 3.1 with 10% orthophosphoric acidat a flow rate of 1.8 ml.min^-1 and the effluent was monitored at 235 nm. Sulfamethoxazole was used as an internal standard.Results: The proposed method was linear in the ranges of 0.5-4.0, 0.75-6.0, 0.75-6.0, 1.0-12.0 and 1.0-12.0 ìg m1-1 for paracetamol, ACA, ascorbic acid, SA and p-chloroacetanilide, respectively. Relative standard deviations for repeatability, reproducibility and recovery were below 2%.Conclusions: In this study, a RP-HPLC method, which is simple, rapid and does not require any separationstep for each drug, was successfully applied for the quantitative assay of paracetamol, ACA, ascorbic acid, and their degradation and toxic impurity products in commercial tablet dosage forms.