Context: There is no straightforward method for estimating cinacalcet HCl in biological materials such as serum exists. As a result, the goal of this research is to develop a simple quality by design (QbD) enabled reverse phase-Ultra-Fast Liquid Chromatography (RP-UFLC) model for analyzing cinacalcet HCl in serum. Aim: The current study envisages the development and validation of an isocratic simple, precise, and rapid QbD enabled RP-UFLC method for the quantification of cinacalcet HCl in both solution form and blood samples. Subjects and Methods: The optimum conditions were outlined, selecting three influential factors (CMPs) i.e. , mobile phase composition, flow rate, and injection volume. Systematic optimization was performed by 3 2 -Box Benkhen experimental design using response surface methodology. The selected variables are further assessed for observed responses Critical Analytical attributes, i.e., peak area, retention time (Rt), USP Plate count. The optimized method used a chromatographic C18 (100 mm × 4.6 mm i.d) column with mobile phase (acetonitrile and Tetrabutyl Ammonium Hydrogen Sulphate [TBSH]) in the ratio of 1:1, with a flow rate of 1 mL/min with UV at λ max 223 nm. The developed method was found to be specific for cinacalcet HCl, enduring no interference of peaks with an overall analytical Rt of 4.3 min. Results: The Accuracy reported as % recovery was found to be 96.83%–101.32% and 95.18%–102.49% respectively. Inter-day precision (reproducibility) and intra-day precision (repeatability) were found to be 0.22–1.19 standard deviation (SD) and 0.14–2.12 SD respectively. The calibration curve was found to be linear with a regression equation Y = 195.8x + 21852, with R 2 0.999 over a concentration range from 100 to 100,000 ng/mL. Conclusion: The required detection and quantitation limits (Limit of Detection and Limit of Quantitation) values were obtained within the acceptance limit based on S/N ratio which indicates the method was sensitive and rapidity of the method. Further, the developed QbD enabled UFLC method was approved and effectively entreated the blood tests to study the pharmacokinetic parameters which indicate a robust, accurate cost-effective method intended for quality control tool for routine systematic analysis in research labs.