Stability of dexamethasone sodium phosphate over a 28 day period when added to commercial veterinary wipe and pad products.

Background - Topical glucocorticoids commonly are used in the management of canine atopic dermatitis to control and prevent allergy flares. Compounding commercial veterinary wipe/pad products to include dexamethasone sodium phosphate (Dex SP) can simplify treatment protocols for owners. Dex SP has not been evaluated for stability when added to wipes/pads. Hypothesis/objective - To evaluate the stability of Dex SP when compounded in three commercial veterinary wipe/pad products containing chlorhexidine. Methods and materials - Dex SP (Dexium, Bimeda; Oakbrook Terrace, IL, USA) was added to TrizCHLOR 4 wipes (TCL; Dechra Veterinary Products; Overland Park, KS, USA), KetoHex wipes (KH; VetOne; Boise, ID, USA), and DOUXO Chlorhexidine Pads (DCP; Ceva Animal Health; Lenexa, KS, USA), creating a 0.04% Dex SP solution. The concentration of Dex SP was measured in μg/mL/wipe or pad in triplicate at Day (D)0, D14 and D28 using liquid chromatography with tandem mass spectrometry. The amount of Dex SP at baseline (D0) was compared to the amount recovered at D14 and D28. Results - The amount of Dex SP in TCL and KH was unchanged between D0, D14 and D28. The amount of Dex SP recovered from DCP on D0 (mean 89.40 μg/mL/pad), D14 (mean 65.58 μg/mL/pad) and D28 (mean 68.09 μg/mL/pad) revealed a significant decline from D0 to D14 (P = 0.004). Conclusions and clinical importance - These data provide evidence that Dex SP is stable for 28 days in TCL and KH, and not in DCP from D0 to D14 or D28 days.