Validation of an UPLC-PDA Method for the Simultaneous Quantification of Phenol and Iomeprol in a Sterile Parenteral Preparation Used for Coeliac Plexus Block, and Its Application to a Pharmaceutical Stability Study.

Objectives: A commonly applied analgesic therapy for patients with severe abdominal pain due to cancer-related pain in the upper abdomen, is coeliac plexus neurolysis (CPN). Herein, a combination product of phenol and an iodine contrast agent are injected simultaneously. The chemical stability of such a combination product is unknown, and no chromatographic method is yet available that describes the simultaneous quantification of phenol and iomeprol. The aim of this study was to develop and validate a stability-indicating UPLC method for the simultaneous quantification of both phenol and iomeprol and to determine the chemical stability of a sterile 100 mg/mL phenol in 350 mg I/mL iomeprol solution for injection during shelf life. Methods: The product was compounded and sterilized in a GMP certified facility. The pharmaceutical analysis was validated by determination of the accuracy, precision, specificity, selectivity, carry-over and linearity. Pharmaceutical product stability was determined before and after sterilization, and during shelf life of 36 months at 25°C ± 2°C. Results: The accuracy for phenol and iomeprol was 97.1% to 99.3% and 100.0% to 100.2%, respectively. The RSD for repeatability and reproducibility for phenol were 0.65% and 1.17%, and for iomeprol 0.61% and 1.49%, respectively. All other tested parameters met the predefined validation criteria. All concentrations at all tested time points remained within ±2% of the initial concentrations for phenol and ±4% for iomeprol. No additional peaks were visible on the chromatograms. Conclusion: A stability-indicating method for the simultaneous quantification of phenol and iomeprol in a parental pharmaceutical preparation was developed and validated. This method was used to demonstrate the chemical stability of a newly developed sterile solution of 100 mg/mL phenol and 350 mg I/mL iomeprol. Chemical product stability was demonstrated during shelf life of up to 36 months.