Determination of amlodipine and atorvastatin mixture by different spectrophotometric methods with or without regression equations

Abstract

Four new, simple, and reproducible spectrophotometric methods were developed and validated for the simulta- neous determination of Amlodipine (AML) and Atorvastatin (AT) in bulk powder and pharmaceutical dosage form. The four methods include two progressive and two successive resolution techniques. The two progressive methods are Absorbance Subtraction (AS) and Amplitude Modulation (AM), while the two successive methods are Constant Value (CV) and Concentration Value. In the Concentration Value method, the concentration of the drugs is determined from the graphical representation without the use of regression equations. Linearity range for the two progressive methods was from 5 μg/mL–35 μg/mL while for the two successive methods was from 5 μg/mL–55 μg/mL. The four methods were validated according to the ICH guidelines and were found to be accu- rate, precise, and selective. The methods were also applied for determination of the mixture in the marketed pharmaceutical dosage form. Results obtained were compared with reported methods. Also, One-way ANOVA statistical test was done between all the proposed spectrophotometric methods where no significant differences were found.