Validation of HPLC, DPPH• and nitrosation methods for mesalamine determination in pharmaceutical dosage forms

Abstract

Mesalamine (5-aminosalicylic acid, 5-ASA) is used because of its local effects in the treatment of inflammatory bowel disease. Therefore, the aims of this work were to compare and validate three analytical methods for the quality control of commercial coated tablets containing 5-ASA: high performance liquid chromatography (HPLC), 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH•) and nitrosation. The parameters linearity, precision and accuracy were studied in this work. HPLC with ultraviolet detection at 254 nm was carried out with a C18 column and a mobile phase constituted of 30 mmol/L monobasic phosphate buffer (pH 7.0) and methanol (70:30; v/v), with 25% tetrabutylammonium hydrogen sulphate. The DPPH• method was performed at 517 nm and using 100 mmol/L acetate buffer, pH 5.5, ethanol and 250 µmol/L ethanolic solution of DPPH•. The nitrosation method was accomplished by using a platinum electrode and standard 0.1 mol/L sodium nitrite as titrant solution. Repeatability (intra-day) and intermediate precision (inter-day), expressed as RSD, were lower than 3%. The experimental recoveries were between 72.5 and 99.9%. Statistical analysis by one-way ANOVA, followed by the multiple comparison test of Bonferroni showed no significant difference among the three methods. All proposed methods can be used for the reliable quantitation of 5-ASA in pharmaceutical dosage forms.