A kind of solid-phase extraction, detection method and kit of doxepin and its metabolite n-desmethyldoxepin

Abstract

The invention discloses a doxepin and its metabolite N-desmethyldoxepin solid-phase extraction, detection method and kit, comprising the following steps: taking a sample to be tested, diluting it with an acidic diluent, and transferring it to an activated on the solid-phase extraction column, and then sequentially washed with alkaline eluent, methanol-water eluent I and methanol-water eluent II, pressed dry, added eluent for elution, and collected the eluted liquid phase part. The method is simple to operate, greatly improves the extraction efficiency, does not need to use complex solvents, and will not cause secondary pollution; through the extraction method of the present invention, the efficient recovery of doxepin and N-desmethyldoxepin is realized, and the recovery of doxepin and N-desmethyldoxepin is achieved in a single In the experiment, the lower limits of quantification of doxepin and N-desmethyldoxepin were 4 pg·mL, respectively. ‑1 , 2pg·mL ‑1 , can meet less than 10pg·mL ‑1 Determination of blood drug concentration, the quantitative sensitivity is significantly better than the current ng·mL ‑1 Level Quantitative Lower Limit.

Description

technical field [0001] The invention relates to the technical field of drug detection, in particular to a solid phase extraction, detection method and kit of doxepin and its metabolite N-nordoxepin. Background technique [0002] Doxepin is a tricyclic antidepressant drug used to treat psychiatric disorders such as major depression, anxiety, insomnia, and obsessive-compulsive disorder. Doxepin Hydrochloride Tablets for the treatment of insomnia characterized by difficulty in maintaining sleep was launched in the United States in March 2010 under the trade name "Silenor". It exhibits potent central anticholinergic activity and inhibits the reuptake of norepinephrine and serotonin pairs. Clinical application shows that low-dose doxepin has high selectivity for H1 receptors. At the same time, doxepin is rapidly absorbed from the gastrointestinal tract and becomes the active metabolite N through demethylation of cytochrome P450 enzyme 2C19. - Desmethyldoxepin (Desmethyldoxepin)...

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Problems solved by technology

Such as NiravP.Patel [2] etc. adopted the liquid-liquid extraction method, and the recovery rate of the two substances obtained was about 62% to 78%, which was basically lower than the recovery rate of 80%, indicating that the liquid phase extraction pretreatment had a significant impact on the treatment of doxepin and its metabolites. extraction efficiency

This extraction method not only requires a large amount of sample, it is difficult to apply to cerebrospinal fluid, whole blood and pharmacokinetic test samples, etc., but also uses a large amount of organic solvent, which is likely to cause pollution to the environment; in addition, the test results show that the extraction process It is easy to extract chemical substances with similar structures together, resulting in high background interference. At the same time, the protein precipitation method also has defects such as that the analyte is diluted by several times of diluent, which is lower than the detection sensitivity of mass spectrometry.

Gong Feijun and others [3] Disclosed is a method for determining doxepin in whole blood by using solid phase extraction (SPE)-liquid chromatography-tandem mass spectrometry, and specifically discloses that the use of an extraction column containing a mixed-type cation-exchange reversed-phase adsorbent has With high selectivity and sensitivity, the detection of doxepin in whole blood is realized, and the extraction recovery rate actually obtained is about 78-82%, but it can also only realize the detection of doxepin singlely and the quantitative range is only 5 ~1000ng·mL -1 , while the human pharmacokinetic parameters show that: oral doxepin 3mg, doxepin C max About 500±200pg·mL -1 , C of N-desmethyldoxepin max About 300±100pg·mL -1 , pharmacokinetics usually requires that the detection method can detect the blood drug concentration after 5 half-lives, therefore, its blood drug concentration after 5 half-lives drops to about 10pg·mL -1 , it is obvious that the existing SPE-HPLC-MS / MS method cannot meet the quantitative requirements of pharmacokinetics in clinical research

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