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Chemical resistance to

disinfectants in medical devices

Eastman Chemical Company

Yubiao Liu, Ph.D., Medical Application Development Scientist

Cynthia Lewis, Marketing Insights and Strategy Manager

Ken Breeding, Sales Specification Associate

Webinar contents

Today’s medical devices are

under pressure.

HAIs and more aggressive

disinfectants

The need for chemical

resistance

Advantages for both clear

and opaque devices

Question and answer

session

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Medical devices under serious pressure

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Patient safety

Performance expectations

(aesthetics, functionality)

Portability and constant

handling

Aggressive disinfectants,

harsh pharmaceuticals,

and carrier solvents

Sterilization

(EtO, gamma irradiation)

Lifetime value

What is an HAI?

Hospital-acquired infection (“nosocomial infection”)

• Patient infection not present or incubating at time of admission

• Includes infections that occur after discharge date

Health care-associated infection

• Infection acquired during treatment:

– In a hospital or other health care setting

– By a patient or health care worker

• Health care settings include not only inpatient acute care

hospitals but also outpatient settings and long-term care facilities

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How HAIs add to the cost of medical care

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Beyond the immediate threat to patient safety

• Longer hospital stays

• Reduced incentives (Medicare reimbursements) for readmissions

that result from hospital-acquired infections

Prevalence

• 8% to 10% of hospital patients were infected in 2009. That

dropped to 1 in 25, or about 4% in 2013.

• Approx. 2M per year in the U.S.

Price tag

• $1K to $65K per infection

• $9.8 billion per year

Are HAIs preventable?

CDC and Medicare have identified 5 types of HAIs as

preventable with proper disinfection and aseptic clinical

protocols:

Central line-associated bloodstream infections (CLABSI)

Catheter-associated urinary tract infections (CAUTI)

Clostridium difficile (C. difficile) infections (CDI)

Surgical site infections (SSI)

Ventilator-associated pneumonia (VAP)

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Attacking HAIs on two fronts

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The health care industry is attacking infections in two ways:

Environmental cleaning

• Cleaning hard surfaces

• Cleaning all equipment that enters a patient’s room

• Cleaning rooms between patients

Aseptic protocols where devices and clinicians contact a

patient

1. Environmental cleaning

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Hospital pathogen Survival time

C. difficile spores >5 months

Acinetobacter spp 3 days to 11 months

Enterococcus spp

(including VRE)

5 days to >46 months

Pseudomonas aeruginosa 6 hours to 16 months

Klebsiella spp 2 hours to >30 months

S. aureus (including MRSA) 7 days to >12 months

Norovirus 8 hours to >2 weeks

Source: Otter, J.A., et al. “Evidence that contaminated surfaces contribute to the transmission

of hospital pathogens and an overview of strategies to address contaminated surfaces in

hospital settings,” Am J Infect Control, May 2013: supplement, pp s6-s11.

As HAI rates fall …

chemical attack on devices increases.

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Chlorhexidine-IPA preparations now dominate the

market.

HAI rates are falling significantly.

Disposable medical parts are subject to higher levels of

chemical attack.

Devices designed for traditional needs are experiencing

performance issues and premature failure.

Source: New Engl J Med. Jan 2013.

Why chemical resistance is important

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Medical applications are especially demanding.

• Lipids

• Medical disinfectants (IPA, chlorhexidine-IPA, bleach,

etc.)

• Hospital cleansers (bleach and others)

• Drugs and carrier solvents

• Bonding solvents used during fabrication

• Adhesives used during fabrication

• Plasticizers in connecting flexible PVC parts

Chemical resistance to disinfectants

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Daily use in a health care setting requires more than

compatibility with disinfectants and disinfectant wipes.

Desirable polymers also provide:

• Low residual stress

• High toughness

• Exceptional clarity (for clear parts)

• Chemical compatibility under stress

• Compatibility with harsh pharmaceuticals and their carriers

• Ability to use bonding solvents and adhesives

• Color stability after sterilization with ethylene oxide (EtO)

and gamma radiation

A closer look

at chemical resistance

Fundamentals of chemical resistance

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“Premature embrittlement and subsequent environmental

stress cracking (ESC) of a material due to the simultaneous

and synergistic action of stress and chemical exposure.”

Details of chemical resistance

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No chemical reaction between polymer and chemical

No polymer chain breakage—physical phenomena

Material would undergo stress cracking given sufficient

time (viscoelastic nature)

Examples of chemical attack

Haze Spotting Stress cracking

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Factors that accelerate chemical attack

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Temperature

Stress concentration (notch sensitivity)

Cyclic loading (dynamic fatigue)

Concentration and exposure time—catalyze the

environmental stress cracking (ESC)

Evaluating chemical resistance

of medical device polymers

Predicting chemical resistance behavior

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Modified ASTM D543 test for chemical resistance evaluation

(inspection for cracking formation and mechanical property changes)

Eastman chemical resistance brochure and ANTEC paper

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What is chemical resistance?

Eastman Tritan™

copolyester MX711

Lipid-resistant

polycarbonate

General-purpose

acrylic

General-purpose

polycarbonate

Chemical resistance with

externally applied stress

The photo on the left demonstrates

the excellent ESC resistance of

Eastman Tritan™ copolyester. An

external stress was applied to the

plaques pictured, and then each

plaque was exposed to Virex™ Tb.

You can see that Tritan resists craze

and crack initiation and propagation,

maintaining the physical integrity of

the molded part.

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Active

ingredients

IPA

Sani-Cloth Plus (3

min)(0.15% quat. ammonium

chlorides + IPA 14.85%)

Super Sani-Cloth (2

min)(0.5% quat. ammonium chlorides +

55% IPA)

Envirocide or

CaviWipes (3 min)(0.28% quat. ammonium chlorides

+22.2% alcohols)

Cavicide 1 or

CaviWipes 1 (1 min)(0.76% quat. ammonium chlorides +

27.5% alcohols)

IPA(100% isopropyl alcohol)

Quaternary

ammonium

chloride

Sani-Cloth AF3 (3

min)(0.28% quat. ammonium

chlorides)

Sani-Cloth HB (10

min)(0.14% quat. ammonium chlorides)

Virex Tb (10 min)(0.28% quat. ammonium

chlorides)

3M Neutral Quat (10

min)(0.84% quat. ammonium chlorides +

<0.2% alcohols + <0.1% Na4EDTA)

Phenolics

(most

aggressive to

plastics)

Vesphene II SE

(10 min)(17% phenols + 5% potassium

hydroxide + <2% sodium

hydroxide)

3M phenolic

disinfectant (10 min)(9.5% phenols + 10% sodium

monoalkyl sulfates + 5% glycol+

5% IPA + 5% sodium hydroxide +

1.5% dodecylbenzenesulfonic acid)

LopHene Germicidal

Detergent (10 min)(14.9% phenols)

Wex-Cide 128 (10 min)(10% phenols + 30% hexylene glycol

+ 5% IPA)

Iodine

Wescodyne (10

min)(5% iodine + 20% phosphoric

acid)

Povidone Iodine 10%

Solution(10% iodine + polyvinyl pyrrolidone)

Iodophor (7% iodine + polyvinyl

pyrrolidone)

Aldehydes Cidex (20 min)(2.4% gluteraldehyde)

Formalin (10 min)(5% formaldehyde)

Cidex OPA (5 min)(0.5% ortho-phthalaldehyde +

10% citric acid + 20% potassium

phosphates + 10% 1H-

benzotriazole + 10% C.I. Acid

Green 25 + 10% HEDTA-Na3)

Peroxide

Renalin 100 Cold

Sterilant(hydrogen peroxide +

peracetic acid + acetic acid)

SPOR-KLENZ (10

min; 30 min steril)(1% hydrogen peroxide + 0.08%

peracetic acid + 10% acetic acid)

Hydrogen peroxide(3% hydrogen peroxide)

HypochloriteSani-Cloth Bleach

(4 min)(0.63% sodium hypochlorite)

Clorox Bleach(8.25% sodium hypochlorite)

Chlorhexidine

gluconate

Chlorohexidine

gluconate(20% chlorohexidine

gluconate)

All examples tested with Tritan grades (time represents manufacturer's contact time required for efficacy).

Sources: Technical data from manufacturer's websites

including marketing collateral, MSDS, SDS, TDB.

Choose strain level

(1.5% for this study)

Constant strain testing, 24-hours exposure

Reverse side impact property testing

Load bars

• 4 bars/sample

• 2 samples/jig

Apply testing chemicals:

• Soak cotton patches

and apply across bars.

• Bag entire jig for

chemicals that evaporate

quickly.

• 24-hours exposure

at room temperature

Measure back impact properties (energy to break).

1 2 3

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Residual property evaluationImpact properties vs. chemical disinfectants

Code % Retention

> 80%

> 60%

< 60%

ChemicalControl

(joules)

Povidone

iodine 10%

(iodine)

Wonder

Woman (IPA)

Envirocide

(IPA, EG

ether)

Cavicide

(IPA, EG

ether)

SPOR-KLENZ

(hydrogen

peroxide)

% Retention of impact energy to break

Eastman Tritan™

copolyester

MX711 (standard)

4.3 103 103 110 108 96

Tritan MX731

(high flow)4.3 91 101 100 106 101

PC (high flow) 5.3 113 78 55 53 104

PC (standard) 5.4 114 31 7 32 103

PC (lipid resistant) 5.5 116 79 76 78 108

Impact modified

styrenic4.3 66 42 110 89 90

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Residual property evaluationImpact properties vs. chemical disinfectant wipes

Code % Retention

> 80%

> 60%

< 60%

ChemicalControl

(joules)

Sani-Cloth AF III

(benzyl quat,

DPG ether)

Sani-Cloth HB

(benzyl quat)

Virex Tb

(benzyl quat,

DEG ether)

Vesphene II

SE (phenolics)

Decon

Disinfectant

(phenolics)

% Retention of Impact Energy to Break

Eastman Tritan™

copolyester MX711

(standard)

4.3 109 112 75 47 14

Tritan MX731

(high flow)4.3 104 109 65 37 21

PC (high flow) 5.3 4 65 All broke

on jig

All broke

on jig

All broke

on jig

PC (standard) 5.4 3 34 All broke

on jig

All broke

on jig

All broke

on jig

PC (lipid resistant) 5.5 3 99 79 All broke

on jig

All broke

on jig

Impact modified

styrenic4.3 29 109 16 53 7

Residual property evaluationTritan MXF121 and competitive opaque materials

against medical disinfectants

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®

®

Code % Retention

> 80%

> 60%

< 60%

Eastman Tritan™ copolyester MXF121 exhibits excellent

chemical resistance against various medical disinfectant

wipes.

PC/ABS shows poor chemical resistance to most screened

medical disinfectants.

ChemicalControl

(joules)

Cavicide (IPA,

EG ether)

Envirocide

(IPA, EG

ether)

Sani cloth AF III

(benzyl quat, DPG

ether)

Sani cloth HB

(benzyl quat)

Wonder

Woman (IPA)

% Retention of impact energy to break

Tritan

MXF1214.8 103 105 103 105 104

PC/ABS 1 6.1 12 10 10 16 12

PC/ABS 2 6.2 8 6 6 11 6

Chemical resistance summary

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Eastman Tritan™ copolyesters have overall good chemical resistance.

When evaluating chemical resistance, one must consider the combination of residual

stress, toughness, and chemical compatibility under stress.

Actual testing of molded articles for the intended application is essential to

meet the FFU requirements.

Eastman TritanTM

copolyesterPolycarbonate Impact modified styrenic

Residual stressLow due to modulus and

longer cooling window

High due to higher modulus

and faster freezing during

melt processing

Undetermined—higher modulus

but longer cooling window

ToughnessHigh toughness—ductile

fracture

High toughness—ductile

fracture

Low toughness—low elongation

to break and brittle impact

Chemical

compatibility

under stress

Does not break with

screened disinfectants,

carrier solvents, and

oncology chemicals

Standard interacts with MCT

oil, Busulfex® carrier solvent,

disinfectants, wipes, Taxol®,

and Etoposide®. High flow is

more susceptible.

Interacts with MCT oil,

Busulfex® carrier solvent, DMAc,

DMSO, Taxol®, Etoposide®,

IFEX® , and Adriamycin®

Overall

chemical

resistance

High Medium Low

Common secondary operations

Solvent bonding

UV adhesive

Ultrasonic welding

Laser welding

Laser marking

TPE overmolding

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Effects of gamma/E-beam sterilization

Less color shift—better aesthetics

and patient comfort, and product

can be shipped much faster

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Gamma sterilization at 50 kGy

Best in class of color retention

property after gamma and

E-beam sterilization

Eastman Tritan™

copolyester MX711

Lipid-resistant

polycarbonate

General-purpose

polycarbonate

Control

After

50 kGy

gamma

Summary

Several tests are available for chemical resistance evaluation:

• Immersion tests, residual property tests (impact and tensile),

and critical strain tests

Test results (and actual end use) depend largely on:

• Polymer and chemical nature

• Stress (either applied or residual)

• Chemical exposure time and temperature

Actual testing of molded articles for the intended application is essential to meet

the FFU requirements.

Eastman Tritan™ copolyesters have the best combination of physical

properties desired for medical device applications.

Tritan copolyesters exhibit an overall excellent chemical resistance property

compared to other clear engineering polymers.

Tritan also offers improved aesthetic and functional integrity following

sterilization by gamma irradiation (and EtO).

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Questions?