Delapril and Indapamide: Development and Validation of a Stability-Indicating Core-Shell LC Method and Its Application for Simultaneous Tablets Assay.

Background : The combination of delapril (DEL) and indapamide (IND) may be regarded as an optimal drug treatment for hypertensive patients. However, there is no published study concerning the suitable stability conditions and evaluation of drugs in the raw material and commercial product. Objective : The aim of the present study was to develop an innovative, high-throughput, and stability-indicating LC method for the simultaneous analysis of DEL and IND in combined dosage form. Methods : Analyses were performed using a core-shell C18 column (100 mm × 4.6 mm id, 2.6 μm) at 45°C using isocratic elution for the mobile phase composed of triethylamine solution (0.3%, pH 5.0)-acetonitrile-methanol (58 + 35 + 7, v/v/v). The separation was obtained within 3.5 min at a flow rate of 1.0 mL/min and UV detection set at 213 nm. Results : The specificity and stability-indicating capability of the method were proven through degradation studies, which also showed that there is no interference of the formulation excipients, showing that the peak is free from any co-eluting peak. Conclusions : The method showed adequate precision, with relative standard deviation values lower than 1.85%. Excellent values of accuracy were obtained, with a mean value of 98.64% for IND and 98.65% for DEL. Experimental design was used during validation to calculate and prove the method robustness. Highlights : The proposed LC method was successfully validated according to International Conference on Harmonisation requirements and applied for the simultaneous determination of DEL and IND in tablets, presenting suitability for stability studies and contributing to improve the QC of pharmaceuticals.