Spectrophotometric quantification of amitriptyline hydrochloride in pharmaceutical tablets: method development and validation.

The development and validation of two uncomplicated, selective, and non-extraction-based visible spectrophotometric methods was carried out for the quantification of a tricyclic antidepressant amitriptyline hydrochloride as pharmaceutical tablets as well as in its pure form. The methods rely on the formation of ion pair complexes between amitriptyline base and two acidic dyes, bromothymol blue and bromocresol purple, which were subsequently measured at 410 and 400 nm, respectively. The developed methods included numerous reaction variables that were examined and improved. Beer's law is applicable under optimal conditions for the bromothymol blue and bromocresol purple methods, respectively, over concentrations from 0.5 to 12.5 μg mL⁻¹ and from 0.5 to 10.0 μg mL⁻¹ amitriptyline hydrochloride. The computed values of molar absorptivity were 1.79 × 10⁴ and 2.32 × 10⁴ L.mol⁻¹.cm⁻¹ for bromothymol blue and bromocresol purple methods, respectively, with Sandell's sensitivity values of 0.0155 and 0.0119 μg cm⁻². Both detection limits and quantification limits were computed and determined to be 0.55 and 1.67 μg mL⁻¹ for bromothymol blue method, and 0.49 and 1.49 μg mL⁻¹ for bromocresol purple method, respectively. The developed methods were successfully applied to estimate the concentration of amitriptyline hydrochloride in bulk form and commercial pills. Therefore, these methods demonstrate promising potential for testing this drug in labs for quality control. Spectrophotometric quantification of amitriptyline hydrochloride in pharmaceutical tablets: method development and validation [ABSTRACT FROM AUTHOR]