Background A paediatric nalbuphine formulation is prepared in the hospital pharmacy of the Nouvel Hôpital Civil of Strasbourg. It was previously checked by HPLC. Following the acquisition of an UV-Raman spectrometer, a method was developed in order to improve the monitoring of nalbuphine preparation.

Purpose To cheque paediatric nalbuphine formulations with a simple, fast and reliable method by using UV-Raman spectroscopy.

Materials and Methods In order to validate a method using the QC-prep (a UV-Raman spectrometer), we prepared three concentration ranges, prepared by diluting three different samples of nalbuphine reconstituted in 0.9% NaCl. Each range was composed of 5 points of calibration. The linearity was validated from the average of the three ranges. The fidelity of the method is tested by repeatability (one solution was sampled five times by the QC-prep) and reproducibility (five different solutions were sampled at one time).

The method is considered as valid if the linearity is good enough (r² > 0.999) and the coefficient of variation (CV) and relative error of repeatability and reproducibility are below 5%.

Results The QC-prep method for nalbuphine 1 mg/ml in 0.9% NaCl is valid in terms of:

• Linearity: the calibration is linear from 0.2 to 2.0 mg/mL (r² = 0.9997)

• Repeatability: the CV is less than 0.25%

• Reproducibility: the CV is less than 2.5%

• Accuracy: the relative error is less than 5%

Five different batches have been checked in routine work. No mistakes have been identified, either in the concentration of the drug (quality control and sample), or in identification of the solvent.

Conclusions Calibration of the QC-prep is simple thanks to easy-to-use software. This is a powerful tool that enables us to determine the concentration of nalbuphine more quickly, easily and safely than the HPLC method previously used. The UV-Raman spectroscopy method could be extended to the analysis of other formulations such as paediatric antibiotics preparations.

No conflict of interest.