10.22376/ijpbs.2019.10.1.p1-12 Volume 11 Issue 4 2020 (October-December) The spectral methods are based on the nature of absorption / emission of electromagnetic radiation by the system being analyzed. The main objective of the study was to develop and validate UV-Visible spectrophotometric methods for the determination of brexpiprazole in pharmaceutical dosage form. Spectroscopic method development for the estimation of brexpiprazole was carried out using UV-VIS spectrophotometer PG Instruments T60 with a pair of special bandwidth of 2mm and 10mm path length matched quartz cells using UV-WIN Software. All the solutions were scanned in the range of 200-400nm with the medium scanning speed. Zero order spectrophotometric method has been developed for the determination of brexpiprazole in 0.1N hydrochloric acid and methanol solution. The maximum absorbance of brexpiprazole was measured at 215nm. Beer's law was observed in the concentration range of 0.5-3.0μg/ml. The above methods were validated with respect to linearity, accuracy, precision, LOD & LOQ and robustness. The mean percentage recoveries were found to be in the range of 98.0 to 102percentage. The percent relative standard deviation (RSD percentage) of inter day precision range was found between 0.306-0.505 percentage and intraday precision range was found between 0.31-0.991percentage. The Percentage RSD values indicate the method was accurate and precise. The newly developed method was extensively validated as per International conference on harmonization (ICH) guidelines. It can be concluded that the proposed method was validated by determining its linearity, accuracy, precision and sensitivity which proves the suitability of the method. Among the various methods available for the determination of drugs, spectrophotometry continues to be very popular, because of their simplicity, specificity and low cost. One of novelty of the developed method was entire method development was performed by using a single solvent and can be applied for the routine estimation of brexpiprazole. Krishnaphanisri Ponnekanti, Gaddam Gouthami Reddy, N Chandana Reddy, Rodda Ojaswini and Thakuri Anitha Brexpiprazole, UV Visible spectrophotometer, Zero order, Beer’s law, limits and percent relative standard deviation. 69-74