Background Desensitisation allows the continuation of a treatment to which the patient has shown hypersensitivity reactions (HSRs) through gradual re-introduction of small amounts of the drug up to filling therapeutic doses. Carboplatin desensitisation protocol is based on three solutions that are usually prepared in centralised units of hospital pharmacies 24 hours in advance in order to optimise workload. There is a lack of stability data for these solutions that are diluted below the minimum established concentration (0.5 mg/mL)

Purpose To determine the stability of carboplatin 0.2 mg/ml solution in 250 ml of 5% glucose and stored in polypropylene infusion bags (carboplatin 0.2 mg/ml solution is a 10-fold dilution for the standard desensitisation protocol using a total dose of 500 mg).

Material and methods We developed a stability indicating method and linearity, accuracy, repeatability, limit of detection (LOD) and limit of quantification (LOQ) that were assessed according to ICH guidelines. Degradation products were characterised.

Carboplatin 0.2 mg/ml solutions were prepared in triplicate and stored at room temperature. Samples were withdrawn at t=0 hour, 3 hour, 6 hour and 24 hour and assayed in duplicate by the high-performance liquid chromatography-UV detection method (Agilent 1200) using an Eclipse-XDB C18, 4.6 × 15–5 mm column. The mobile phase used was methanol/water: 2/98. Flow=1 ml/min.

Stability was defined as retention of at least 95% of the initial carboplatin concentration.

Physical stability was assessed by visual inspection.

Results The HPLC method was found to be suitable for the stability study. The correlation coefficient of the calibration curve was 0.9997. LOD=0.69 mcg/mL and LOQ=2.1 mcg/ml. Degradation products were clearly separated from the carboplatin peak.

The mean percentage of the initial concentration remaining was >95% for all samples over all the study time. After 24 hours, no concentration variations and no macroscopic alteration were observed.

Conclusion Carboplatin 0.2 mg/ml desensitisation solution can be considered stable for 24 hours at room temperature in 5% glucose polypropylene infusion bags.

These results allow carboplatin desensitisation solutions to be prepared in advance in order to optimise the workload in the chemotherapy preparation units.

References and/or Acknowledgements Ficha técnica de Carboplatino. Centro de Información online de Medicamentos (base de datos en Internet). Agencia Española de medicamentos y productos sanitarios (AEMPS).

No conflict of interest