Powdered Activated Carbon (PAC) has been used for many years in the pharmaceutical (API) industry. Its purpose is to remove impurities from API processes. These impurities are typically either coloured by-products, dissolved catalysts or other more complex species.
PAC is produced by either chemical or steam activation. Steam activation leads to a greater number of micropores (less than 100nm) and mesopores (100nm to 1μm), while chemical activation produces more open macropore (>1μm) structures. Careful selection of how the PAC has been activated is important to match the optimum activation to the type of species that need to be removed.
In addition to activation method the adsorption efficiency of PAC is affected by the number of active sites on the carbon, and other process parameters such as contact time, temperature, pH, and concentration of contaminant.
PAC is still considered a viable way to de-colorize solutions / adsorb contaminations however GMP is causing many API manufacturers to have concerns with the ongoing use of powdered carbon.
Traditionally a process involves adding PAC, re-circulating and then filtering to remove. This presents operators with many Health and Safety concerns along with the challenge of removing the recovered PAC, the inconvenience of handling left over carbon and the risk of carbon fines breaking through to the final crystallization therefore requiring at best costly rework or worse scrapping of the drug substance.
Meeting the needs of the API Industry, 3M Purification pioneered the immobilization of PAC in its 3M™ Zeta Carbon™ Range which offer over 40 different types of carbon in its product range. Such an extensive portfolio is important as source material and activation method are the key to performance rather than just quantity of PAC.
GMP is a requirement for many regulatory authorities. To meet these guidelines many companies have moved to the 3M ZetaCarbon system as PAC immobilized within the filter matrix reduces many of the concerns and simultaneously delivers improved yields and reduced cost of ownership.
ZetaCarbon is a lenticular style cartridge that immobilizes PAC in its structure. This produces a stable and torturous path through which the contaminated liquid is forced to flow. The impurity and activated sites of the PAC are therefore brought into close proximity improving the performance removal and ultimate efficiency of the PAC to adsorb impurities.
Health and Safety is improved as there is no longer an exposure to PAC Dust and since used in sealed systems it reduces operator exposure to the active drug and Hot Toxic Solvents that are typically used in the manufacture of API.
Processes now run cleaner meaning more manageable batch to batch cleaning and significantly enhanced robustness to preventing carbon fines entering the final drug substance.
This improves reproducibility, reduces failed batches and solvent contamination which are all key drivers to improving efficiency and reducing the total costs of ownership.
To discuss any of these applications or your specific requirements with one of our Technical Sales Engineers or Application Specialists contact us