Enantiomeric analysis of overlapped chromatographic profiles in the presence of interferences. Determination of ibuprofen in a pharmaceutical formulation containing homatropine

- U-PLS was applied to measure enantiomeric ratio of partially overlapped signals.
- Enantiomeric ratios of ibuprofen below 0.5% were determined with excellent precision.
- Accurate results were obtained even when the minor peak overlaps with interferents.
- The method was validated and applied to ibuprofen contents in pharmaceuticals.
- Low enantioresolution values would not prevent of obtaining quantitative results.

In this work, we studied the combination of chemometric methods with chromatographic separations as a strategy applied to the analysis of enantiomers when complete enantioseparation is difficult or requires long analysis times and, in addition, the target signals have interference from the matrix. We present the determination of ibuprofen enantiomers in pharmaceutical formulations containing homatropine as interference by chiral HPLC-DAD detection in combination with partial least-squares algorithms. The method has been applied to samples containing enantiomeric ratios from 95:5 to 99.5:0.5 and coelution of interferents. The results were validated using univariate calibration and without homatropine. Relative error of the method was less than 4.0%, for both enantiomers. Limits of detection (LOD) and quantification (LOQ) for (S)-(+)-ibuprofen were 4.96 × 10−10 and 1.50 × 10−9 mol, respectively. LOD and LOQ for the R-(−)-ibuprofen were LOD = 1.60 × 10−11 mol and LOQ = 4.85 × 10−11 mol, respectively. Finally, the chemometric method was applied to the determination of enantiomeric purity of commercial pharmaceuticals. The ultimate goal of this research was the development of rapid, reliable, and robust methods for assessing enantiomeric purity by conventional diode array detector assisted by chemometric tools.