Development and Validation of Stability-Indicating High Performance Liquid Chromatographic (HPLC) and DD₁-Spectrophotometric Assays for Etodolac in Bulk Form and in Pharmaceutical Dosage Form

Abstract

A stability-indicating reversed phase high performance liquid chromatographic assay procedure has been developed and validated for etodolac. The liquid chromatographic separation was achieved isocratically on C₁₈ Zorbax ODS using a mobile phase containing methanol: water: acetic acid (70:30:0.1%, v/v/v), at a flow rate 1 mL/min and UV detection at 254 nm. The method was linear over the concentration range of 2.4–16 µg/mL (r = 0.9999) with a limit of detection and quantitation of 0.03 and 0.10 µg/mL, respectively. Another method was applied for the determination of etodolac in the presence of its degraded products using the first derivative ratio spectrophotometry (DD₁) at 293 nm using 1000 µg of degraded etodolac as a divisor. The method was linear over the concentration range of 10–50 µg/mL (r = 0.9999). Both methods have been found to have the required accuracy, selectivity, sensitivity, and precision to assay etodolac in bulk form and in pharmaceutical dosage form. Degradation products resulting from the stress studies did not interfere with the detection of etodolac, which indicates that the assays are stability-indicating assays.

Keywords:

• Etodolac
• HPLC and DD₁-Spectrophotometry
• Stability-indicating

ACKNOWLEDGMENT

The authors are sincerely indebted and profoundly grateful to Professor Dr. Mohamed Nabil Aboul Enein. Professor of Pharmaceutical Chemistry, Department of Pharmaceutical and Medicinal Chemistry, National Research Centre, for his endless support, guidance, and unlimited valuable advice throughout this work.

Notes

^a n = Number of determinations.

^b The values in parentheses are corresponding to the theoretical values of t and F at (P = 0.05).