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Pilot study to quantify the time to clear dexamethasone from plasma and urine of adult horses following a single nebulisation
Author(s) -
Symonds NE,
Dart AJ,
Keledjian J,
Lau M Liu,
Ennis LC,
McIver VC,
Tsang AS,
Biasutti SA,
Jeffcott LB
Publication year - 2019
Publication title -
australian veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.382
H-Index - 59
eISSN - 1751-0813
pISSN - 0005-0423
DOI - 10.1111/avj.12800
Subject(s) - urine , horse , dexamethasone , dexamethasone sodium phosphate , chemistry , chromatography , sodium , medicine , biology , biochemistry , paleontology , organic chemistry
Objective To quantify the time to clear dexamethasone from plasma and urine of horses following a single nebulisation. Design Experimental using six Standardbred mares. Methods Dexamethasone sodium phosphate (0.04 mg/kg) diluted in 0.9% sodium chloride was administered as an aerosol using a Flexineb E2® nebuliser. Blood samples (0, 2, 4, 6, 8, 10, 12, 24, 32, 48, 72 and 96 h) and urine samples (0, 1, 4, 8, 24, 32, 48, 72 and 96 h) were collected for analysis using liquid chromatography mass spectrometry. Results Maximum plasma concentrations (t max ) were reached by the earliest detection point (2 h) after nebulisation (0.6–1.8 ng/mL), but was no longer detectable at 48 h. However, in one horse 0.1 ng/mL was found at 96 h after three consecutive readings of 0 ng/mL. The t max in urine was reached by the earliest collection point (1 h) after nebulisation (3.2–23.8 ng/mL), but was no longer present in urine at 72 h in five horses, while detectable levels (0.1 ng/mL) were still present at 96 h in one horse. Conclusions A single dose of 0.04 mg/kg of DSP administered as an aerosol through a FlexinebE2® mask was no longer detectable in blood at 48 h in six horses tested, but one horse returned a reading of 0.1 ng/mL at 96 h after having no detectable levels. Dexamethasone was not detectable in urine at 72 h in five horses but was detectable at a low concentration (0.1 ng/mL) at 96 h in one horse.