Fuente: WIPO "industrial hemp" The invention relates to a method for extraction and separation of cannabinoids from industrial hemp, designed for medicinal purposes, and also the preparation of an extract, not containing tetrahydrocannabinol, and the preparation of maximum refined individual cannabinoids.
The advantage of the method according to the invention consists in the preparation of an extract from hemp, which contains at a high percentage medically useful cannabinoids and doesn't contain undesirable admixtures and tetrahydrocannabinol, so that it can be used without any restrictions as a pharmaceutical. Moreover, the method allows the possibility of separation, if required, into individual useful cannabinoids as pure compounds, in ecological terms, without environmental pollution, as it is according to the most synthetic methods. The possibility of producing pure compounds represents a great contribution to the research of substances, related to a concrete medical application and the preparation of various combinations thereof, with the objective of expansion the field of application. The method is also cost-effective.
The method consists in that the extract, obtained in accordance with various methods, undergoes a centrifugal countercurrent liquid-liquid chromatography, as the operation includes a centrifugation of solvents and the extract, obtained during the previous operations; the solvents form two phases, the phase, which the extract is dissolved in, is mobile, and the other one is stationary, whereby the mobile phase passes through the stationary phase, wherein several amounts of the components of the extract content are captured; this passing of the mobile phase through the stationary phase is repeated many times, until separation of the desired substances, which are analyzed in a familiar way, whereby as stationary phase solvents are used, which are selected from the group of straight-chain and branched-chain hydrocarbons, produced from crude oil, straight-chain and/or branched-chain alcohols, straight-chain and/or branched-chain ketones, straight-chain and/or branched chain carboxylic acids, straight-chain and/or branched-chain nitriles, gases in supercritical and subcritical condition, like carbon dioxide, nitrogen, nitrogen oxides, water with modified acidity with or without salts of organic and non-organic substances dissolved therein, as for example NaSO3, carbonate compounds or mixtures of the above-mentioned solvents, and as mobile phase solvents are used, which are selected from the group of straight-chain and branched-chain hydrocarbons, produced from crude oil, straight-chain and/or branched-chain alcohols, straight-chain and/or branched-chain ketones, straight-chain and/or branched chain carboxylic acids, straight-chain and/or branched-chain nitriles, gases in supercritical and subcritical condition, like carbon dioxide, nitrogen, nitrogen oxides, water with modified acidity by organic and/or inorganic acids and bases, as well as Lewis acids and bases in the interval from 0 to 14 pH, with or without salts of organic and non-organic substances dissolved therein, as for example NaSO3, carbonate compounds, or mixtures of the above-mentioned solvents, while the choice of the solvents between the two phases is conditional on that, they shall be different and immiscible with each other; the centrifugation revolutions and the flow speed of the mobile phase are designed (calculated or determined experimentally) depending on the total phase volume; thus at the finish of the process the tetrahydrocannabinols and/or the tetrahydrocannabinol acids are separated from the remaining cannabinoids and/or cannabinoid acids in the solution, the other cannabinoids in the process can also be separated as a pure substance, separate in a solution and the solvents are evaporated respectively, in order to obtain a pure substance.