Development of miniaturized extraction procedure based on liquid-liquid dispersive microextraction (DLLME) for analysis of 11-nor-”9-tetrahydrocannabinolcarboxylic acid in urine samples

• Grant number: 19/02845-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): June 01, 2019
• Effective date (End): July 31, 2020
• Field of knowledge: Health Sciences - Pharmacy - Toxicological Analysis
• Principal Investigator: José Luiz da Costa
• Grantee: Leonardo Costalonga Rodrigues
• Host Institution: Faculdade de Ciências Farmacêuticas (FCF). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Associated research grant: 17/02147-0 - Single drop chromatography and its coupling to mass spectrometry: instrumental strategies, development of materials, automation and analytical applications, AP.TEM

Abstract

Cannabis is an angiosperm that includes different species. In general, these plants have more than 70 are cannabinoids, including delta-9-tetrahydrocannabinol (THC). When smoked, THC is rapidly absorbed and is readily distributed to the brain and other organs. Excretion of THC from the body occurs mostly through hydroxylated and carboxylated biotransformation products, whether or not conjugated with glucuronic acid. Among acid metabolites, THC-COOH conjugated to glucuronide acid is the main product of urinary biotransformation, whereas THC-OH predominates in feces. Cannabis involves controversial issues regarding its legalization. On the one hand, its therapeutic potential leads to the possibility of approval of the plant or isolated cannabinoids for medical purposes. On the other hand, there is evidence that its use affects neural connections in the central nervous system, leading to dependence and behavioral disorders. Sample preparation is one of the fundamental stages of an analytical process. Because of this importance, several studies have been dedicated to the development and optimization of new extraction procedures. Liquid-Liquid Extraction (LLE) requires considerable organic solvent volumes, involves several steps (difficult to automate) and sometimes low extraction (recovery) yields. The dispersive liquid-liquid microextraction (DLLME) is a miniaturization of the LLE technique considered to be very simple, fast and inexpensive. The technique is based on a ternary system of solvents, where a quick injection with a syringe is made of a mixture of two organic solvents - one acting as a water miscible solvent, and the extracting solvent, generally of high density, immiscible in the aqueous sample containing the analytes of interest. This mixture produces a turbid solution containing fine extractive solvent droplets completely dispersed in aqueous phase with an exchange surface area, allowing an effective extraction and high concentration factor of the analytes in the extracting solvent. The aim of the present work is to develop and validate an analytical method for the analysis of THC-COOH (main product of THC biotransformation) by DLLME and gas chromatography coupled to sequential mass spectrometry (GC-MS / MS). The developed method can be used for laboratory diagnosis of intoxications caused by these toxic agents. The DLLME extraction procedure will be optimized during the development stage. After optimization, the experimental procedure developed should use a small volume of urine (less than 0.5 mL) and organic solvents, an environmental friendly procedure.