Less Noise, Less Heat with Mobile Isolation Chamber
The evolution of the use of mobile isolation chambers in hospital pharmacies was described by Henry Rahe of Containment Technologies Group, Inc., Indianapolis, IN. European hospital pharmacies started using barrier/isolation technology over five years ago.
The development of barrier/isolation technology for pharmacy applications in Great Britain began with mixed results. Initially units were manufactured without consideration of the application, resulting in misuse and improper maintenance of the equipment. To correct these errors the British established a group, drawing from the users, manufacturers and regulatory people, to develop a guide for the manufacture and use of isolators in hospital pharmacy applications. This work was completed in 1994.
In the United States, barrier / isolation technology is following the same evolution with a greater time lapse. This lag can be contributed to the difference in the source of regulatory control. In the U.S., regulatory control of hospitals is a state agency responsibility, resulting in differences on a state-by-state basis.
The beginning elements for development of the mobile isolation chamber (MIC) started with a hospital pharmacist's dissatisfaction with the limitations of her laminar flow hoods. This need, combined with an engineer's awareness of and respect for the capabilities of barrier / isolation technology, helped initiate the plan for the development of the mobile isolation chamber (MIC).
The major advantages of the mobile isolation chamber over laminar flow hoods were less noise, less heat and the mobility of the unit.
The four basic components of such an MIC unit are: the physical structure or shell of the unit, the air quality or filter and air handling system, the transfer technologies both for product and personnel interactions, and the monitoring systems.
Stainless steel was chosen for the shell because of its durability, in an environment containing needles and other sharp objects. Experience, in the sterility testing units in the pharmaceutical industry, has shown testing and replacement of (soft shell) 'bubble' units not to be cost effective. Another factor, contributing to this decision, was the flexibility stainless steel allows in the selection of cleaning and sanitizing agents. The integrity of the shell is the core of this technology and must be designed, constructed and validated to a standard which will assure containment of the internal environment.
For the MIC system, it was decided to use nonlaminar flow air and instead, use HEPA filtration for both the entrance and discharge filters. Utilizing this approach with recirculation of more than 90 percent of the air, air quality of less than Class 10 was observed during validation of the unit.
Selection of the two-piece glove sleeve arrangement was based upon the customer profile. Typically, several different people would be using the system during a work shift. The range of hand sizes were significant and the requirement for manipulation important, which pointed to the use of individual sized gloves that could be changed quickly. The separate glove sleeve type arrangement had both functional and economic advantage for this application.
Because of the advantages in movement of a variety of material sizes and shapes the air lock alternative was chosen for movement of materials (5).
