Stability of Diluted Desmopressin Acetate Intranasal Solution at 0.01 mg/mL

Objective: In pediatrics, weight-based doses can be very small, leading to measuring tiny volumes of the commercial desmopressin nasal solution at 0.1mg/mL, which reduces precision and increases the risk of error. Since stability of the desmopressin acetate solution diluted at 0.01 mg/mL has not been properly demonstrated, the aim of this study was to demonstrate its 180 days physicochemical stability when stored in clear glass vials at 5°C and 25°C. Glass vials are used for their simplicity and user-friendliness.

Methods: The desmopressin acetate solutions were prepared by diluting a commercial nasal spray (0.1 mg/mL) with 0.9% sodium chloride to achieve a concentration of 0.01 mg/mL and aliquoted in clear glass vials. Stability study encompassed the samples being subjected to incubation at 5 ± 2°C and 25 ± 2°C/60 ± 5% RH for up to 180 days. Evaluation at specific intervals involved withdrawal of 1 mL aliquots for inspection of organoleptic properties and desmopressin acetate concentration assays using the HPLC-UV method. The particle count analysis was also performed on freshly prepared solutions at the initial time point and at the end of the study. The necessary microbiological tests were also carried out.

Results: The HPLC-UV method for desmopressin acetate quantification demonstrated robustness and low intraday variability (r2 = 0.999, highest RSD 0.40%). Stability studies over 180 days revealed no notable changes in odor and color, with consistent assay results and particle count evaluation meeting USP <788> criteria. No bacterial growth was noted.

Conclusion: Desmopressin acetate prepared at 0.01 mg/mL from commercial nasal solutions using 0.9% sodium chloride when stored in clear glass vials at 5°C and 25°C remained stable for up to 180 days.