Estimation of uncertainty for measuring desloratadine in tablets formulation using UV spectrophotometry

Analytical results are not complete unless they are expressed with their measurement uncertainty. Overall uncertainty may be control by controlling the most significant sources of uncertainty. The aim of this work was to establish a procedure to estimate measurement uncertainty of a validated UV spectrophotometric method for quantification of desloratadine in tablet formulation. UV spectrophotometric method was linear (r = 0.9972), accurate (mean recovery = 100.8%), precise (RSD = 2.4%), and robust. Using Eurachem/Citac guide, uncertainties associated to preparation of desloratadine CRS and sample solutions were the most significant, contributing with about 54.7% and 40.9%, respectively. Using method validation approach, uncertainties associated with precision and accuracy were the most important, contributing with about 52.9% and 30.7%, respectively. Overall uncertainties obtained using Eurachem/Citac guide (98.2 ± 1.1%), method validation approach (98.2 ± 1.2%) and Monte Carlo simulations (98.2 ± 1.1%) were closed to each other, which indicates that the equations proposed in this work were suitable for measuring uncertainty in routine analysis. Moreover, at least 2 independent replicas were necessary to guarantee an appropriate precision regarding the specification limits. Therefore, the proposed UV spectrophotometric method was suitable for measuring desloratadine in tablet formulation with the required accuracy, precision and measurement uncertainty.