Development of Spectrophotometric Methods for Aliskiren Determination

Two simple, accurate and precise spectrophotometric methods for the determination of Aliskiren (ALS) in pharmaceutical products were developed. The first method was based on the reaction of ALS with 1,2-naphthoquinone-4-sulfonate (NQS) in alkaline medium producing an orange-red colored product, which absorbs maximally at 500 nm. The second method was based on the reaction of ALS with ninhydrin (NIN) mixed with ascorbic acid as reducing agent in phosphate buffer pH 6.0 producing blue-violet colored product, which absorbs maximally at 569 nm. The experimental parameters for both methods were studied and optimized. Beer's law was obeyed in the concentration range of 20-300 and 10-170 µg/ml with R2 of 0.991 and 0.992 for NQS and NIN methods, respectively. The validity of the methods was assessed according to International Conference on Harmonization (ICH) guidelines.