Cannabinoid purification

So, the 20th century actually led to an almost total disappearance of C. sativa for medicinal purposes. The only source for THC, which became the focus of scientific research, was fhe rafher fedious exfracfion and purification from confiscated hashish or marihuana. In 1972 the first commercially viable total synthesis of A9-THC was established and it became the first cannabinoid available as a modern medicine in the form of soft gel capsules (the active ingredient being called dronabinol from tetrahydrocannabinol) under the trade name Marinol for the prevention of nausea and vomiting during cancer chemotherapy. 

The purest form of the drug produced for illicit use is cannabis oil. This is prepared by solvent extraction of the resin followed by further purification to produce an oil that comprises up to 60% cannabinoids. Cannabis oil is generally added in small quantities to tobacco and smoked. 

Purification of Cannabinoids by High Pressure Liquid Chromatography (HPLC) (15,16)... 

The large instability of A -tetrahydrocannabinol in acid solution (16,18), implies that the drug may be significantly degraded in the normal stomach. Again, this intimates that oral administration may not be an optimum route on which to establish dose-response correlations. Furthermore, the choice of a cannabinoid as an internal standard is very critical since it must not give any interference with the other related compounds, unless a HPLC purification step is included in the procedure. Cannabinol which, at times, has been taken as a possible metabolite (19-21) of A9-tetrahy-drocannabinol, may only be an artifact of the analytical procedure since disproportionation of 1 occurs readily. 

To reduce interference from endogenous fats, the extract was partially purified by chromatographing five successive 20pl extract injections (equivalent to 0.5 ml milk each) on a MicroPak CN-10 column. A gradient elution program from hexane to 5% methanol in dichloro-methane was used for the purification step. The elution region corresponding to the neutral nonpolar cannabinoids was collected from each run. The fractions were then combined and analyzed on another MicroPak CN-10 column. 

Zafiriou PM, Karava V, Boutou E, Vorigas CE, Maccarrone M, Siafaka-Kapadai A. Partial purification and characterization of a fatty acid amidohydrolase (FAAH) from Tetrahymena pyriformis. 2004 Annual Symposium on the Cannabinoids, International Cannabinoid Research Society, Burlington VT, p. 146. 

The on-line OPLC method was used for the isolation of hemp constituents (91). The cannabinoid acid fractions were analyzed by different spectroscopic methods without further purification. 

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