Preliminary study of the stability of dexamethasone when added to commercial veterinary ear cleaners over a 90 day period

Abstract

Background Topical corticosteroids are commonly used in the management of allergic otitis externa to diminish inflammation. A common strategy is to make compounded solutions of dexamethasone in ear cleaner. Hypothesis/Objectives The objective of this study was to determine the stability of dexamethasone when added to four commercial ear cleaners (ec): designated ecA, ecB, ecC and ecD. Methods and Materials Two concentrations (0.1 and 0.25 mg/mL) of dexamethasone were formulated for each cleaner solution from a 2 mg/mL solution and stored in the original manufacturers’ bottles at two temperatures: room (22 ˚C) and refrigerated (4 ˚C). Samples were evaluated in triplicate, using liquid chromatography‐tandem mass spectrometry at 10 time points over 90 days. The mean and standard deviation were calculated for each time point. Results A solution was considered stable if the dexamethasone value remained >90% of the target concentration. All dexamethasone solution values were stable to 90 days, except two solutions for ecA; the 0.25 mg/mL dexamethasone concentration was only stable to 14 (4 ˚C) and 21 days (22 ˚C). Conclusions and clinical importance These results provide preliminary evidence in support of pharmaceutical stability data for dexamethasone when included in the above compounded solutions at the noted concentrations and temperatures.

The stability and in vitro antibacterial efficacy of enrofloxacin and gentamicin solutions against Staphylococcus pseudintermedius over 28 days

“…The experimental period was set at 28 days based on the results of previous studies and taking into consideration the time for which these off‐label solutions might be applied in clinical practice. Previous studies have observed the stability and efficacy of compounds for 28 days and ≤90 days 11–13 . In most cases, the stability and bactericidal efficacy of these compounds was maintained.…”

“…Previous studies have observed the stability and efficacy of compounds for 28 days and ≤90 days. [11][12][13] In most cases, the stability and bactericidal efficacy of these compounds was maintained. One study showed that the concentration of amikacin stored in plastic liquid bottles was significantly increased on D56 and that this was related to evaporation.…”

“…Sometimes, veterinary practices use or recommend off‐label combinations for the treatment of OE 10 . However, very few studies have investigated the stability and efficacy of these off‐label compounded solutions 11–13 . Generally, these studies compared the efficacy of the combinations of various injectable antibiotics or glucocorticoids with that of commercial ear cleaners.…”

Long‐term non‐surgical management of canine aural tympanokeratoma with repeated removal of middle ear keratinous debris and CT follow‐up

“…Dexamethasone has been reported to be stable in three different ear cleaners for 90 days, but only for 14-21 days in one cleaner. 31 These differences in stability could be caused by differences in the concentration of dexamethasone and the pH of the solution. In another study, the chemical stability and bactericidal efficacy of enrofloxacin were demonstrated to be good in four different ear cleaner solutions over a 28-day period.…”

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

“…7 Veterinarians often compound products in-house to simplify topical canine AD treatment protocols and improve client compliance, such as the addition of dexamethasone to ear cleaners. 8 Addition of dexamethasone sodium phosphate (Dex SP) to antiseptic wipes would be a convenient way to simplify topical therapy protocols for pet owners. However, it is important to evaluate the stability of compounded products to avoid treatment failure.…”