Processes and apparatus for extraction of active substances and enriched extracts from natural products
View Patent ↗Processes for preparing extracts of natural products such as plant material, and for preparing purified extracts from crude extracts of natural products, by extraction with hot gas. Apparatus suitable for use in preparing extracts of natural products are also described.
1. A process for preparing a cannabinoid-rich extract from cannabis plant material or a crude solvent extract thereof loaded onto an inert matrix material, comprising contacting the cannabis plant material or crude solvent extract with a heated gas at a first temperature and then with a heated gas at a second temperature which is greater than the first temperature, greater than 105° C. and sufficient to volatilize one or more cannabinoids to form a vapour but does not cause pyrolysis of the cannabis plant material or crude solvent extract, and condensing the vapour formed at the first and/or the second temperature to form a cannabinoid-rich extract, wherein the cannabinoid-rich extract prepared by the process is substantially free of terpenes, wherein the heated gas is a reducing gas or a non-oxidising gas, and wherein the crude solvent extract is a soft extract prepared by maceration, percolation or reflux extraction and contains inactive material or ballast.
2. The process according to claim 1 , wherein the cannabinoid-rich extract prepared by the process is substantially free of ballast.
3. The process according to claim 1 , wherein the cannabinoid-rich extract prepared by the process is substantially free of fats, waxes, carbohydrates, proteins and sugars.
4. The process according to claim 1 , wherein the cannabinoid-rich extract prepared by the process is substantially free from waxes, sterols and other lipid soluble components.
5. The process according to claim 1 , wherein the heated gas is forced upwardly through the cannabis plant material, which is retained in a perforated container, or the crude solvent extract.
6. The process according to claim 1 , wherein the heated gas is blown onto the cannabis plant material or crude solvent extract.
7. The process according to claim 1 , wherein the cannabis plant material or crude solvent extract is subjected to continuous agitation.
8. The process according to claim 7 , wherein the continuous agitation is effected by subjecting the cannabis plant material or crude solvent extract to a rotary action.
9. The process according to claim 1 , wherein the cannabis plant material or crude solvent extract is presented to the heated gas in a counter-current manner.
10. The process according to claim 1 , wherein the cannabis plant material is still green plant material and the process further includes a pre-treatment step in which the cannabis plant material is contacted with a heated gas at a temperature which is sufficient to dry the cannabis plant material.
11. The process according to claim 1 , wherein the reducing gas is nitrogen, carbon dioxide, helium or argon.
12. The process according to claim 1 , wherein the non-oxidising gas is dry steam.
13. The process according to claim 1 , wherein the reducing gas is steam to which has been added sodium metabisulphite in a quantity sufficient to produce 10-500 parts of sulphur dioxide per million parts of the cannabis plant material.
14. The process according to claim 1 , wherein the vapour is treated to remove any particulate matter prior to the condensation step.
15. The process according to claim 1 , wherein the temperature of the heated gas used to volatilize one or more cannabinoids is varied in two or more discrete steps.
16. The process according to claim 1 , wherein vapours formed at the first and the second temperatures are condensed and collected in separate fractions.