Determination of Moxidectin in Serum by Liquid Chromatography-Tandem Mass Spectrometry and Its Application in Pharmacokinetic Study in Lambs

Abstract

The widespread use of moxidectin (MOX), a parasiticide used in the sheep breeding, has induced the parasite resistance in Brazilian farms. As a consequence, the farmers often increase the dose and frequency of drug utilization, and disregards safety of meat or milk. In order to establish adequate therapeutic treatment it is necessary to know the pharmacokinetics of the drug in the animal's body. Thus, high performance liquid chromatography-electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS/MS) method was developed for the determination of MOX in serum lamb. Serum samples were treated with acetonitrile to precipitate proteins. A clean up by dispersive extraction in solid phase (SPE-d), using primary/secondary amine (PSA) and C18 sorbents, followed by freezing was performed. Method validation presented precision (coefficient of variation) and accuracy (recovery%) between 1.7-6.7 and 80.0-107.3%, respectively. The limit of quantification (LOQ) of the method was 2.0 ng mL -1 and a linear response was obtained over a range of 2.0 to 100 ng mL -1 . This method was successfully applied to the determination of MOX in serum from suffolk lamb to evaluate the pharmacokinetic profile. Keywords: serum lamb, moxidectin, veterinary drug, pharmacokinetic, LC-MS/MS IntroductionThe infections with gastrointestinal nematodes have constituted major obstacle to the expansion of the sheep industry in Brazil. The gastrointestinal parasitism is associated with physiological changes in animals, such as bowel dysfunction and nutritional stress that result in decreased body condition, lower weight gain and death of animals. Among the most important parasites that affect sheep flocks we can highlight the Haemonchus contortus. The parasiticide agents allowed for controlling endo and ecto-parasites in sheep, the macrocyclic lactones, have been widely employed over the world because of its high efficiency and broad-spectrum activity.2 The moxidectin (MOX) (Figure 1), semisynthetic derivative of nemadectin, is a macrocyclic lactone obtained by the fermentation of Streptomyces cyanogriseus. 3 In the last decade MOX has emerged in sheep flocks in Brazil due to its efficacy against a wide variety of nematodes and arthropod parasites, even at extremely low doses. 4 However, similarly as occurred with other drugs, indiscriminate use of MOX could induce parasite resistance, affecting the efficiency of the drug.5 Actually, similarly to ivermectin and the benzimidazole, parasite resistance against MOX has been reported in Brazil. 6 As an action of parasite resistance control, alternatives have been studied in order to minimize the spread of animal diseases and the damage to the breeding and may be referred: correct management and grazing, proper sheep nutrition, selection of resistant animals, biological control, use of vaccines, herbal medicine and/or the use of techniques for assessing the degree of infection. 7Chromatographic methods for the determination of MOX in plasma from different species (alpacas, cattle, horses, pig, rabbit and s...

Development and Validation of a Reliable UHPLC-MS/MS Method for Simultaneous Quantification of Macrocyclic Lactones in Bovine Plasma

“…As can be seen in Table 2, LOQ values of 1 ng/mL were reached for IVER, DORA, and MOXI which was the same as the previous report by Croubels et al, 2002 [26] and was more sensitive than the previous studies reported in lamb tissues [21,22] and lamb serum22 [23]. This LOQ was low enough to allow quantification of the MLs after 4 h and until 35 days after a single subcutaneous administration of 0.2 mg/kg BW of IVER, DORA, and MOXI to cattle.…”

“…The back-calculated concentrations of the analytes in each calibrator sample fulfilled the criterion for accuracy (results not shown). Calibration curves were broader than those reported elsewhere by Croubels et al, 2002 [26], Baptista et al, 2017 [23], and Morbidelli et al, 2018 [25].…”

“…A schematical overview of the final sample preparation procedure for quantification of IVER, DORA, and MOXI in bovine plasma is indicated here (see Figure 1). Compared to other methods in the literature, the current method is fast and simple to apply since drying and reconstitution steps were absent with less solvent consumption; moreover, the procedure is rather inexpensive, since OstroTM 96-well plates are substantially cheaper than conventional SPE columns [23,25] and samples do not need to be filtrated using 0.22 µm filters or transferred into autosampler vials, and hence, can be directly injected from the 96-well collector plate onto the LC-MS/MS instrument. As a result, the developed sample preparation procedure is suitable for large sample set extraction within a short period of time.…”

“…LC-MS/MS also allows accurate simultaneous analysis of mixtures in biological matrices, such as plasma. A few studies have been reported for quantification of MLs using LC-MS/MS methods in biological matrices, such as in milk [20], lamb tissues [21,22], and lamb serum [23], human [24], dog [25], and calf [26] plasma.…”

A Review on Different Analytical Techniques for Quantification of Moxidectin

“…The outcomes of precision, accuracy, LOD, and LOQ were found to be within the limits, according to the method validation. (26) Subbarao et al validated a rapid bioanalytical approach for the determination of moxidectin in cattle hair. Using a liquid-liquid extraction, moxidectin was isolated from cow hair using methyl tert-butyl ether as the solvent and Sorenson's buffer as the digesting solvent for incubation.…”