Enhanced Recovery of Pharmaceutical Solvent driven by EPA Initiative - Summary
Enhanced Recovery of Pharmaceutical Solvent driven by EPA Initiative
The United States Environmental Protection Agency (EPA) is establishing new safeguards for
hazardous secondary materials with objectives to promote the economic, environmental, and public health
benefits of recycling wastes, with an emphasis on several industrial sectors, including the pharmaceutical
industry. On average, pharmaceutical manufacturers use at least 100 kg of solvents to make 1 kg of active
pharmaceutical ingredient. EPA has determined that the environmental impacts from solvents used as
manufacturing and processing aids could be significantly reduced if the product life of solvents used for these
purposes were extended to more than a single use. By encouraging the safe recycling of wastes EPA hopes to
reduce the life cycle risk of these wastes.
Many of the solvents of interest to the EPA form mixtures with water that are difficult and/or energy-
intensive to separate with conventional separation technologies such as distillation. Energy-efficient, cost
effective, and otherwise non-polluting alternative technologies would make solvent recycling more feasible.
The net effect of the EPA proposed safeguards is that these will strongly incentify pharmaceutical
manufacturers to recycle process solvents.
There are numerous needs in the pharmaceutical industry to use and recover high purity solvents. Key
uses include: high purity alcohol, the ability to develop low-cost dewatering of solvents and a relative gentle
and simple process for dewatering solvent under mild conditions. Compact Membrane Systems (CMS)
proposes a novel membrane process that can lead to extremely high dewatering rates with high separation
capabilities based on a family of chemically inert amorphous perfluoro membranes operating under a wide
range (almost universal) of operating conditions. CMS’s dewatering process is compatible with existing
pharmaceutical solvent (PS) processing. Therefore, from a chemical stability standpoint, it can be operated
with alcohols, organic acids, ketones, amines and aprotic solvents, to name a few. Since CMS membrane’s
high flux is based on its high free volume and perfluoro nature, there is little need for concern about chemical
interaction with the species present, and the actual permeability does not change significantly with water
activity. Therefore, we have a potentially universal and simple system that can work on a wide range of PS for
a wide range of applications under varying water activity. To enhance the potential for “universal” PS
dehydration, CMS will develop A) membranes with enhanced water/solvent separation and B) more resistant
system which equates to more resistant porous supports. CMS has recruited a number of key companies for
supplying key materials and subsequently marketing the final product.
CMS has acquired the resources (people and facilities) to prepare perfluoro copolymers which are not
available elsewhere and which possess a new range of properties. Although the familiar monomer
tetrafluoroethylene (TFE) is too hazardous for handling by a small company, a variety of other fluorinated
monomers are safe to handle. Many copolymers have now been prepared by CMS. By not using TFE in our
synthesis, we eliminate potential explosions and contact with potential carcinogens. Also we do not use
PFOA/C8 surfactants as an additional precaution.
During Phase II CMS will build a dehydration system and demonstrate dehydration of a number of
solvents including methanol. Given our innovative success in Phase I with porous supports and special
perfluoropolymer membranes, these materials will be used whenever existing porous supports and
membranes do not work well. While we have been very successful with special perfluoropolymer membranes
for enhanced solvent dehydration, this work has been exclusively using small laboratory-scale membranes.
Phase II will focus on scaling up the membrane size and demonstrating it on real systems (i.e., working with
pharmaceutical companies and the EPA).
