Background
- Closed system transfer devices (CSTD) such as Cyto-Set® (1), PhaSeal® (2), and Equashield® (3) are designed to reduce hazardous drug exposure from preparation to administration (4)
- While these devices protect staff and have been provided an ONB designation by the FDA, as aclosed system they can also minimize microbial contamination because the devices are airtight and leak-proof, potentially preventing microbial ingress.
- Equashield® was rated favourably in terms of ease of use and therefore used as the chosen CSTD for this study (4,6)
- Objectives
- We undertook this study to test whether attaching Equashield® adaptors to simulated single-use vials (Tryptic Soy Broth 20 mL vials):
- Could prevent or minimize microbial contamination and extend the “use-by” date following multiple withdrawals under extreme-use-conditions
- Could verify the results of previously published data (5) applied to real-world conditions with multiple staff members and multiple areas at Sunnybrook Health Sciences Centre Pharmacy
Methods
- Each lot of TSB growth medium was secondarily tested as a positive control by inoculation with less than 10-2 of S. epidermidis ATC 12228, incubation at 37oC and review at 24 and 48 hours afterwards
- As a negative control, an unopened vial of TSB 20 mL from each lot was incubated for the duration of the study
Figure 1
Result
- All positive control vials demonstrated growth within 48 hours
- All negative control vials showed no growth throughout the study
- All accessed vials remained sterile following storage at room temperature for 5 days and subsequent incubation for 14 days
- None of the 192 vials (B & C) accessed 1440 times showed evidence of contamination. The 95% confidence interval of the contamination rate is 0.000 to 0.035%
- None of 96 vials with CSTD attached but without broth removed demonstrated contamination
Table 1
Cost saving implications
- Annual drug wastage in the cancer centre pharmacy, adhering to chemical stability and preparation in an ISO Class 5 environment, but not discarding partial vials after 6 hr as per USP<797> was ~$185,000 in 2014/15. This represents ~1% of drug expenditures.
- Annual estimates of drug wastage in 2015/16, abiding USP<797> would be in excess of $2.7M.
- If we were to use a CSTD on every single use vial in our system, the drug cost savings to our system is estimated to exceed $2.5M annually.
- The incremental cost of the CSTD within the outpatient oncology program is estimated at $400,000 annually, based on drug expenditures of $20.4M and approximately 25,000 patient treatment visits.
- Net cost savings would be ~$2.1M
Conclusion
- Attachment of a CSTD adapter to single-use
vials within an ISO-5 environment has the
ability to maintain sterility following multiple
withdrawals - These results were consistent when the vials
were exposed to continuous ISO 5 air quality
and when exposed to poorer than ISO 5 air
quality (Laminar air flow hood off) - These results remained consistent in the
setting of multiple operators following training
on the use of the CSTD
Figure 2
