Novel Techniques for Containment
Recently published scientific papers feature various aspects of pandemic “star” Coronavirus 19. This virus has significantly changed pharma research and production in a variety of unique ways.
This white paper will focus on how research/production efforts might fail under the threats of highly contagious disease viruses, bacteria, and highly active pharmaceutical ingredients. Performing contemporary research safely and producing highly active pharmaceuticals and vaccines will require material isolation and medical product purity. Once identified, contamination paths and bad production procedures will require correction and control.
We will outline possible contamination vulnerabilities in this paper. Flow Sciences and other manufacturers are developing containment options to neutralize such challenges and test methods to certify them. The author will discuss several current enhancements already used and new approaches we are all developing right now!
Where Containment May be Challenged in Today’s Environment:
1.) Collision of Energy Conservation with Containment Challenges
ANSI/AIHA Z 9.5 sets acceptable control levels for chemical fume hoods at stricter levels today than twenty years ago, while stricter energy conservation requirements mandate historically lower exhaust rates for the same equipment in most new facility designs. Recommended containment control levels using ANSI Z 9.5 are now 0.050 ppm as installed1 or lower 2. Twenty years ago, this level was double this value at 0.10 PPM 3.
In spite of achieving mandated containment improvements, a variety of contamination vectors are still possible, particularly with recently reduced exhaust volume requirements established to conserve energy.
2.) Researcher and operator aerosol contamination from Covid 19 carriers:
COVID-19 follows a person-to-person transmission pattern that occurs primarily via direct contact or through droplets spread by talking or coughing from an infected individual. One hundred eighty eight countries have confirmed Coronavirus cases so far 12. Even though transmission vectors are somewhat limited, they work very well for this virus. Not for us humans.
Mass-transportation has also become a vulnerable breeding facilitator13,14. The Diamond Princess Cruise ship harbored in Yokohama, Japan, Holland America’s MS Zaandam cruise ship 6, and various aircraft incidents show how people housed in close quarters can suffer widespread contagion through this limited contact mechanism compounded by a large number of elderly passengers.
Similar to SARS, CoV2, and SARS CoV, the earliest Covid 19 Chinese field studies found active virus in the same rooms as Covid patients 4. In addition, other studies point to contagion in family units 5.
As Covid 19 testing becomes more available, it will be easier to stop infectious people from contaminating lab areas or production facilities by testing, tracing, and isolation. It is also possible to use personal protective equipment (PPE) in particularly sensitive areas.
3.) Measurement of toxic or contaminant leakage outward from a containment device due to poor airflow or electrostatic attraction is less straightforward. For years, the ANSI/ASHRAE 110 test has prescribed diffusion of SF6 gas into chemical fume hood interiors and evaluated quantities that escape containment using a mannequin with an attached air sampler that measured ppm amounts of SF6 in the mannequin-breathing zone.
While ASHRAE 110 is not designed to evaluate powder or biological containment, it is nonetheless frequently used for these applications in coordination with a variety of powder tests.
Electrostatically charged powders can stick to the hands of an operator and “hitch a ride” out of the containment area. Air currents may or may not be effective in containing materials exiting the area using this mechanism. Specific additional testing addresses this concern, and FSI has published results comparing ASHRAE 110 tracer gas testing against surrogate powder testing. Results of such tests are beginning to build a comparative record in which we can be confident!
Containment equipment manufacturers generally run ASHRAE 110 tests followed by particulate studies, which provide high-level verification of containment under field conditions. Covid 19 and highly potent pharmaceuticals have only increased the likelihood of using these approaches in tandem to assess containment.
While powder and biocontainment tests developed for pharmaceutical evaluations are today recognized and useful, their conditionality, complexity, and expense have thus far prevented establishment of a broad record of consistent test results from which to build a reference containment standard similar to ASHRAE 110. Unfortunately, it may be next to impossible to generalize powder testing as the industry has done with tracer gas testing as the additional electrostatic vectors of containment escape are so situational that simulated process containment testing (as-used) of particulate escape may be the only answer to confidently apply a given containment approach.
We do not wish to leave this topic languishing in the swamp of pessimism. The current pandemic has given us several opportunities to use what we have learned containing powders in the related field of viral control.