Preparative Isolation And Purification Of Alkaloids Through Chromatography
Isolation is the most important step that helps determine and characterise pure alkaloids. As these pure alkaloids differ in polarity and thermal stability, specific chromatographic methods are used for the efficient isolation of these compounds. First of all, alkaloids are extracted from the respective plant source, and then the targeted alkaloids are isolated and purified using chromatography.
Preparative Chromatography is one of the most generic methods to purify small drug molecules and significant chemical components. It is the best method for isolating even smaller quantities of material, like anything >0.1 g.
Preparative Chromatography helps obtain sufficient quantities of compounds at the desired purity, and in this process, the highest throughput of the targeted compound is obtained at the lowest price. And the best part is that the scale of preparative chromatography is larger than that of conventional analytical chromatography, hence helping to isolate even the smaller quantities of sample.
Most of the active constituents obtained from the plants are alkaloids; hence various advancements have been made in the field of extraction, isolation and purification of alkaloids, and it has led to the development of optimum methods for the isolation of particular alkaloids of interest from the mixture without causing any undesirable alterations to them. Among these developments, regular modification of adsorbents presents the user with better options in hand. The adsorbent selection is the most important parameter for the efficiency of the isolation and purification process.
Silica gel is the most frequently used stationary phase in Column chromatography. Its weak acidic property may be the reason for the adsorption of alkaloids, especially when the isolation is being carried out with non-polar solvents. Also, when using silica gel, choosing the correct particle size of silica gel powder becomes important as it impacts the formation of a column which can again ‘make or break’ the isolation process.
Aluminium Oxide Basic is a better option for selecting the stationary phases for drug purification via column chromatography. Although they don’t mark frequent usage in the market, and that’s because awareness about it being the better option has just started to unfold and would take the momentum in coming years as it is certainly an option without any limitations. Many big industries have even started going for this. With Aluminium Oxide Basic, neutral solvent systems can be used. It is always advisable to use basic adsorbents for the stationary phase because an acidic adsorbent may cause a chemical reaction between alkaloids and the adsorbent (used as the stationary phase), leading to undesirable changes in the targeted molecules.