Centrifugal Partition Chromatographic Technique to Purify CBD

Cannabidiol CBD
Cannabidiol CBD
CBD Products
CBD Products

CBD is the trending product in the world markets now, and is attracting the attention of more and more people due to its health benefits. CBD is a cannabinoid that is obtained from the hemp plant, a member of the plant family Cannabis sativa. CBD products have a high concentration of cannabinoid and minimal concentration of THC, which is an intoxicating compound.

THC concentration in hemp CBD is only 0.3% or less, which led to its legalization in 2018 in the US. The Farm Bill of 2018 removed CBD from the list of Federal Controlled Drug Substances and classified it as an agricultural product.

Purification of CBD ensures that the concentration of THC in it does not exceed the 0.3% limit, and there are several techniques of varying efficiencies available for the purification of CBD. Centrifugal Partition Chromatography (CPC) is a famous purification method. CPC was developed as an alternative to traditional purification methods like High-Performance Liquid Chromatography (HPLC).

Why Is CPC Preferred To HPLC?

HPLC requires a large number of solvents, and the silica resin used in the process is very expensive, which increases the cost of the overall purification process. The method cannot achieve a level of purification as obtained using CPC.

General Purification Steps of Hemp Extract

Dry hemp plants undergo several steps till they acquire the final purified form and those steps are discussed below.

Liquid/Solid Extraction

To extract chemical compounds from the hemp plant, solvents like ethanol or carbon dioxide are used and a dry extract containing waxes, cannabinoids, and lipids is obtained.

Winterization

Removal of unwanted products from dry extract is the purpose of this step. Diluting the dry extract in ethanol and storing it at the freezing point of ethanol for 24 hours helps in removing waxes and lipids from the extract.

Filtration

To remove particulate matter and precipitates from the extract, the vacuum filtration method is used and a micron range of 0.45 and less is selected for the filter.

Dry Down

The ethanol that was used during extraction has to be removed from the extract. The vacuum distillation process or evaporation method using a rotatory evaporator can be used in the dry down step.

How Does CPC Purification Work

The CPC purification is a liquid/liquid chromatographic technique, and all the processes take place inside a CPC column. A two-phase system is formed in the purification process by mixing two immiscible liquids in the column. The liquid phase containing the required compounds is used as the mobile phase, and the other liquid phase is used as the stationary phase, which is held stationary inside the column by centrifugal force.

Both phases mix up when the mobile phase is fed into the column under pressure, and in the process, molecule exchange takes place between the phases. Different solutes diffuse at different rates and get collected at different points.

The effects and legality of a CBD product are determined by the CBD and THC content in it, and the efficacy of the purification process ultimately determines these factors. Faults in the purification step will put the effectiveness and legal status of a CBD product at risk.