LC-MS/MS method for determining milbemycin oxime content of animal plasma

Abstract

The invention discloses an LC-MS / MS method for determining the milbemycin oxime content in animal plasma and belongs to the fields of veterinary drug content determination, pharmacokinetics and residue law. The method comprises the following steps of: adding 4mL of acetonitrile and 0.3g of sodium chloride into 1mL of plasma sample, mixing and then centrifuging the mixture, drying the supernatant by blowing nitrogen gas, adding 3mL of methanol and 5mmol / L of ammonium acetate into the residue in a ratio of 1:9, purifying the mixture by a C18 solid extraction column; and using a liquid chromatography-mass spectrometry instrument for analysis under the following conditions: electrospray ionization, nitrogen gas spray pressure of 49psi, spray voltage of 4800V, nitrogen gas pressure of 20psi, temperature of 300 DEG C, Source CID of 12V; m / z of 536, detection of fragment ions of which m / z is 536 by the full scan, composition of mobile phase by acetonitrile and 0.5mmol / L of ammonium acetate in a ratio of 85:15, flow speed of 0.25mL / min, and column temperature of 20 DEG C. The method has the characteristics of fastness, sensitivity and low detection limit.

Description

technical field [0001] The invention belongs to the field of veterinary drug content determination and pharmacokinetic research, and relates to a method for determining the content of veterinary drugs in biological samples, in particular to a method for determining the content of milbexime in animal plasma and a sample pretreatment method. Background technique [0002] Milbemycin is a macrolide anti-endoparasite drug, and it is an oxime derivative of Milbemycin A3 and A4. It paralyzes the parasite mainly by enhancing the release of the inhibitory neurotransmitter γ-aminobutyric acid of the parasite Death, usually used to prevent heartworm disease, control dog and cat diseases caused by nematodes, hookworms and whipworm disease in dogs. In 1997, the Taiwan region of my country launched Beimaixin produced by Taiwan Novartis Co., Ltd. with milbexime as the main component. As an oral medicine for preventing heartworm and intestinal parasites in dogs and cats, it was the first ap...

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Problems solved by technology

[0003] The methods currently used for the detection of macrolide antiparasitic drugs include thin-layer chromatography, immunochemical method and high-performance liquid chromatography, among which thin-layer chromatography is mainly used for the detection of ivermectin in cow feces. Degradation evaluation, experimental operation is cumbersome and time-consuming, and fluorescent derivatives are easy to degrade; immunochemical methods have strong cross-reactivity; high-performance liquid chromatography has a great advantage because of its high separation ability. The application of anti-parasitic drug detection is more and more extensive, including ultraviolet detector, fluorescence detector, mass spectrometry detection, etc., because ultraviolet detection is not sensitive enough, it is mainly used for samples with high drug content; fluorescence detector detection involves To derivatization, although the derivatization method is becoming more and more mature, from the initial reaction time of ten hours to tens of seconds now, the stability of the derivatized product has also improved, but the 5-position of milbexime has The oxime group has multiple conjugated diene structures, and the derivatization products are complex, which is not conducive to detection, and the detection limit of this method can only reach 0.5 μg / mL, which is far from meeting the needs of low-level detection in plasma samples; especially in In the study of pharmacokinetics and drug residues, when the drug concentration in biological samples such as plasma and tissue is extremely small, the above-mentioned determination methods are difficult to meet the detection requirements; while LC-MS / MS is a chromatographic technique with mass spectrometry as the detection method. It combines the high separation ability of liquid chromatography with the high sensitivity and high selectivity of mass spectrometry, and has great advantages in the quantitative analysis of drugs.

However, there is no such method for the determination of milbexime in animal plasma

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