Subcritical extraction to prevent undesirable components in natural active pharmaceuticals

Natural extracts are worldwide sought as sources for active principles. Pharmaceuticals specifications include impurities restrictions. Subcritical CO2 conditions may avoid co-extraction of undesirable components.

Pharmaceuticals extracts without impurities

Natural extracts are worldwide sought as sources for active principles. Pharmaceuticals specifications include impurities restrictions. Subcritical conditions may avoid co-extraction of undesirable components.

Pharmaceuticals are required to meet impurities limits. Natural active principles extraction are usually accompanied by other non desirable substances present in the natural matrix as minor components.

A lot of those natural pharmaceuticals ingredients, obtained by extraction, require purification processes to ensure not to exceed these specifications. Typical refining processes include extraction, distillation, crystallization and others which can result in thermal decay, oxidation or rancidity.

Supercritical extraction represents a competitive alternative to solvent methods since it permits to carry out extraction, fractionation and refining steps in just one process. Adsorption techniques are often integrated in the same process so as to result in retention of small amounts of impurities and undesirable components inevitably extracted in the same conditions of the targeted family of substances.

There are a number of different mechanisms by which  this may occur, normally due to close solubility values or because a low concentration of that interesting component is obtained simultaneously  together with other very low solubility but higher presence component.

Capability of supercritical CO2 to include separation steps, at the same time that extraction, is a well known plus to be considered in strategies to design new natural active principles or even to succeed in a more refined current active ingredient.

Subcritical CO2 for pure active principles

However, dense gases are not limited to supercritical conditions; in particular, CO2 presents special features when used in SUBCRITICAL CO2 conditions, essentially polarity and hence solubility. This near critical point liquid phase widens the range of application of this fluid towards selectivity increase as for preventing extraction of unwanted impurities.

Different adsorbent materials can also be used within this technology in order to provide maximum separation capabilities along with the extraction process to find the most effective available extracts.

The purest pharmaceutical can be achieved by using this simple but efficient, cheap, clean and sensitive technique.

Extraction Technology – Altex, S.A