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Evaluation of The Sterility of Single-use Vials Undergoing Multiple Access Following Application of a Closed System Transfer Device (CSTD)
Perks W, Carating H, Iazzetta J, Charbonneau LF, Walker SE

Evaluation of The Sterility of Single-use Vials Undergoing Multiple Access Following Application of a Closed System Transfer Device (CSTD)

Department of Pharmacy, Sunnybrook Health Sciences Centre and Leslie Dan Faculty of Pharmacy, University of Toronto.
Perks W, Carating H, Iazzetta J, Charbonneau LF, Walker SE
Toronto, Canada


  • 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


  • 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


  • 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


  • Attachment of a CSTD adapter to single-use
    vials within an ISO-5 environment has the
    ability to maintain sterility following multiple
  • 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

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  1. Gebel J. Evaluation of the microbial tightness of closed system transfer devices by simulating airborne and touch contamination. Critical Care. 2015;19(Suppl 1):P85.
  2. Edwards M, et al. Cost savings realized by use of the PhaSeal(R) closed-system transfer device for preparation of antineoplastic agents. Journal of Oncology Pharmacy Practice. 2013;19(4):338-347.
  3. http://www.capho.org/sites/default/files/nops/Evaluation%20of%20a%20New%20Closed%20System%20Transfer%20Device% 20-%20Flay%20Charbonneau.pdf
  4. Vyas N, et al. Occupational exposure to anti-cancer drugs: A review of effects of new technology. Journal of Oncology Pharmacy Practice. 2013;20(4):278-287.
  5. Rowe E, Savage S, Rutala W, Weber D, Gergen-Teague M, Eckel S. Economic and Microbiologic Evaluation of Single-Dose Vial Extension for Hazardous Drugs. Journal of Oncology Practice. 2012;8(4):e45-e49
  6. Heather Scott, Susan Singh, Flay Charbonneau. Evaluation of a New Closed System Transfer Device. Canadian Association of Pharmacy in Oncology Conference. St. John’s, Nfld. May 21-24, 2015.