Development and Validation of an HPLC Method for Oxytocin in Ringer's Lactate and its Application in Stability Analysis

Abstract

Oxytocin is an important therapeutic peptide; it is commonly used for the induction and augmentation of the first stage of labor. A simple, isocratic, reproducible, and selective HPLC method was developed and validated to study oxytocin stability in Ringer's Lactate. A C₈ column with mobile phase of acetonitrile and potassium dihydrogen orthophosphate buffer 0.05 M, pH‐7.0 (20:80, v/v) at a flow rate of 1.25 mL/min was used. The detection wavelength was 220 nm and 100 µL of sample was injected. Ethyl p‐aminobenzoate was used as the internal standard (I.S.). The retention time for oxytocin and I.S were 8.5 and 17 min, respectively, with a total run time of 20 min. Solid phase extraction was used and a lower limit of quantitation (LLOQ) of 0.0075 USP units/mL could be achieved. The method showed excellent linearity in the range 0.0075–0.9 USP units/mL. Oxytocin recovery ranged from 80–99%. Precision and accuracy were within the acceptable limits. The method was used to estimate oxytocin concentrations in Ringer's Lactate over an extended period of time.

Keywords:

• Oxytocin
• HPLC
• Validation
• Ringer's lactate
• Stability

Acknowledgments

The authors acknowledge help rendered by Melanie Huebner and Navin Goyal, Department of Pharmaceutics, University of Florida, Gainesville, USA during the project.