a review of medical device and optical critical cleaning · low foaming or high foaming depending...

A Review of Medical Device and Optical Critical Cleaning

Presenter: Malcolm McLaughlin | Date: 04/04/2019

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Introduction

Malcolm McLaughlinVP, Product & Business Development30+ years detergent formulation, cleaning process development, cleaning validation, and analytical residue detection experience

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Critical CleaningWhat is critical cleaning?

Cleaning that impacts the value of the finished output from whatever is being cleanedTypically some observation, measurement or validation is done related to precision cleaningCritical cleaning in FDA or USDA regulated industries of components or substrates is the complete removal of undesirable contaminants to a desired preset level.The preset level is normally the minimum level at which no adverse effects take place in a subsequent operation.

Define Critical Cleaning

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Medical Device and Optic Cleaning = Critical Cleaning

Numerous examples within the medical device and optic industries of the perils of not focusing on critical cleaningMedical Device Industry

Major hip implant manufacturerOptic Industry

Optical Malfunction

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Why Precision Cleaning and Cleaning Validation is Important – Infamous Example

Cleaning failures can be very costlyOne company tried to bring a cleaning/passivation process in house and save less than $2.00/deviceHowever the cleaning/passivation processes were not properly validated and due to the thought that well, we don’t need to do that cleaning validation and waste time… there was tragedy

Medical Device Example

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Why Precision Cleaning and Cleaning Validation is Important – Infamous Example

What happened????The company had to recall nearly 25,000 hip implants, 17,500 of which had already been implanted in patients, needing explantsThis catastrophic series of events lead to the destruction of this large medical device company as a stand alone company.

Medical Device Example

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Optics Example

A well established German optic company Residues on the surface causing diffraction of lightCouldn’t have any damaging ingredients Couldn’t have any rinse aids or corrosion inhibitors

Used Liquinox to clean lenses are eliminate light diffraction and accurate transmission problems

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4. The 9 Variables of Effective CleaningIt is not only the cleaner that determines cleaning success; remember the 9 variables: BATH-O-CARD

1. Before-clean 6. Chemistry/Conc.2. Agitation 7. After-clean3. Time 8. Rinsing4. Heat 9. Drying5. Orientation

Critical Cleaning: Cleaning Process Development and Optimization

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1 Before-Cleaning HandlingClean surfaces as soon as is practical after

they are dirtyDried on residues are more difficult to clean

than fresh onesPre-soaking can help remove dried on

residuesStoring parts in a cleaner environment prior

to cleaning makes them easier to clean

Cleaning Process Development and Optimization

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2 AgitationUse high foaming or sometimes low foam detergentsManual SoakUltrasonic

Use low foaming detergentsAutomatic Spray WasherDishwasher Sprayball Clean-In-Place


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3 Time and Cleaning Effectiveness

For digesting mechanisms, time vs. cleaning is linear Allow time especially for enzyme methodsSoaking requires time: can take hoursCooler solutions take more time (every 10 deg

C


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4 HeatCleaning speed doubles every 10°C (~20°F)

increase

Above the melting point of waxes and greases, emulsification rather than just dispersion can occur; over 77°C (170°F) often effective


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5 Orientation – Cleaner can access all surfaces

Blind holes Dead legs in piping systemsShadowed surfaces in automated spray

cleaningCoverage inside dishwasherNot pooling solution inside a dishwasherOrient for drainage


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6 Chemistry Low foaming or high foaming depending on agitation Low foam for high agitation, pressure sprayHigh foam and sometimes low foam for manual, soak and

ultrasonic

Alkaline high pH, neutral pH, or acidic low pHResidue typeWorker safety Substrate compatibility

Chelation capacity to compensate for hard water


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6.1 Chemistry and Soil TypeNatural Oils - higher alkaline cleanersSynthetic and Petrochemical Oils - wetting, emulsifying; typically mild alkalineSalts, Oxides, Metals - alkaline chelating, sequestering cleaners, best with acid cleanersParticulates - dispersant cleanersProtein/biofouling - protease enzyme cleaners; mild alkaline with wetting agents


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6.2 Chemistry pH and CleaningType Cleaner pH Typical Soils Mineral acid 0-2 heavy scales Mild acid 2-5.5 salts, oxides,

metallic Neutral 5.5-8.5 light oil and particle Mild alkaline 8.5-11 oils, particles, films Alkaline 11-12.5 natural oil, fat, resin Corrosive 12.5+ heavy grease/soils


Type Cleaner

pH

Typical Soils

Mineral acid

0-2

heavy scales

Mild acid

2-5.5

salts, oxides, metallic

Neutral

5.5-8.5

light oil and particle

Mild alkaline

8.5-11

oils, particles, films

Alkaline

11-12.5

natural oil, fat, resin

Corrosive

12.5+

heavy grease/soils

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6.3 Chemistry and Substrate TypeAluminum/soft metal - mild alkaline to modest acid (pH 2.5-9.5); silicated alkalineMild Steel - corrosion controlled rinse/dryMost Plastics/resins - ok w/ broad range of aqueous cleaners; check solvent contentStainless steel - ok with most alkaline detergents

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7 After cleaning

Handle and store cleaned surfaces in clean areas

Store away from humidity or heat if appropriate


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8 Rinsing and Cleaning Effectiveness

Rinse water is the last to touch the surfaceEvaporation deposits rinse water contentDeionized - lower in metals, can be carbon

filtered for low organics – may need UV/0.2 micron filterDistilled - lower in organics/microbes


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8 Rinsing and Cleaning Effectiveness (Cont.)

Reverse osmosis - best of both; costlyCooler rinse = less corrosionRinse/wash temp same to avoid break

emulsionRinse hot for easier evaporation drying


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9 Drying and Cleaning EffectivenessEvaporation deposits rinse contaminants,

may promote corrosionBlowing, wiping-off rinse water alleviates

problems, but is difficultParticle sensitive drying may require filtered

air dryingHumidity on cleaned surfaces can cause

corrosion


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Process ConclusionSelecting the right cleaner is easier if you

understand the 9 variables that effect cleaning performanceMatch your cleaner to the cleaning method,

substrate, and type of residue


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Medical Device Case StudyProblem: calcium salt residues from metalworking fluid were not being cleaned by alkaline cleaning processSolution: Use an appropriate acidic cleaner such as Citranox® detergent under typical medical device cleaning conditions:

Agitation: 40 KHz ultrasonic tankTime: 20 minutes clean, 2x10 minute Heat: 140-150 deg F (60-65 deg C)Orientation: rack mounted to keep devices separated to avoid trapping residues and dirty wash solutionChemistry: 2% Citranox (2.5 oz/gal or 20 mL/L)Rinse: 140-150 deg F (60-65 deg C) counter flow cascade rinse with 5% rinse volume exchange in 10 minutes using deionized waterDry: Blow off with dry filtered nitrogen

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Optics Case StudyProblem: Precision optics being inappropriately etched by alkaline cleaner being used to remove waxes and resinsSolution: Use a milder pH Liquinox® detergent under typical precision optical cleaning conditions:

Agitation: 130 KHz ultrasonic tankTime: 20 minutes clean, 2x10 minute Heat: 110-120 deg F (45-50 deg C)Orientation: rack mounted to keep devices separated and allows free drainingChemistry: 1% Liquinox (1.25 oz/gal or 10 mL/L)Rinse: 110-120 deg F (45-50 deg C) counter flow cascade rinse with 5% rinse volume exchange in 10 minutes using deionized waterDry: Filtered air oven dryer

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Throughput and Time Optimization

Applying BATH-O-CARD concepts:10 deg C increase doubles cleaning speedIncrease chemistry concentration for bath lifeOptimize substrate orientation for cleaning and rinsing speedIncrease agitation to increase cleaning speedUse the correct chemistry for faster cleaningLow foaming cleaners can rinse faster

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ConclusionThe successful manufacturing and functioning of both medical devices as well as optics rely on effective cleaningUnderstanding the basics of cleaning and detergents will lead to proper detergent selectionUnderstanding the process factors in the design of a cleaning process may influence the success of your product and avoid disaster

Slide Number 1 IntroductionCritical Cleaning�Medical Device and Optic Cleaning = Critical Cleaning�Why Precision Cleaning and Cleaning Validation is Important – Infamous ExampleWhy Precision Cleaning and Cleaning Validation is Important – Infamous ExampleOptics Example4. The 9 Variables of Effective Cleaning 1 Before-Cleaning Handling2 Agitation3 Time and Cleaning Effectiveness4 Heat5 Orientation – Cleaner can access all surfaces6 Chemistry6.1 Chemistry and Soil Type6.2 Chemistry pH and Cleaning6.3 Chemistry and Substrate Type7 After cleaning8 Rinsing and Cleaning Effectiveness�8 Rinsing and Cleaning Effectiveness (Cont.)9 Drying and Cleaning EffectivenessProcess ConclusionMedical Device Case StudyOptics Case StudyThroughput and �Time OptimizationConclusion

a review of medical device and optical critical cleaning · low foaming or high foaming depending...

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