Process validation of Sterilization & Water Process Systems

GUIDED BY Presented by Dr. K. Kishore Kumar Ms. V. Gouthami

256213886029

STERILIZATION VALIDATION

• Sterile products have several unique properties such as

1. Free from micro organisms

2. Free from pyrogens

3. Free from particulates

4. High standards of purity and quality

References: [1,2,3, & 4]

Methods of sterilization of products

HEAT:-1. Moist heat-auto clave2. Dry heat-hot air oven GAS:-1. ethylene oxide2. Peracetic acid3. Hydrogen peroxide(vapor phase)4. Chlorine di oxide

References: [5& 6]

Radiation

1. Gamma rays

2. Beta rays

3. Ultraviolet

4. Microwave

References: [5& 6]

Validation of steam sterilization cyclesQualification and calibration 1. Mechanically checking ,upgrading, and qualifying the

sterilizer unit

Selection and calibration of thermocouples• Cu constantan wires coated with teflon are a popular choice as

thermocouple monitors

• Accuracy of thermocouples should be ±0.5°C. Temperature accuracy is especially important in steam sterilization validation.

• Thermocouple accuracy is determined using NATIONAL BUREAU OF STANDARDS (NBS) traceable constant temperature calibration instruments.

• Thermocouples should be calibrated before and after validation experiment at 2 temperatures i.e. 0C & 125 C .

• New thermocouple-recording devices are capable of automatically correcting temperature

• Any thermocouple that senses a temperature of more than 0.5 C away from the calibration temperature bath should be discarded

• Temperature recorders should be capable of printing temperature data in 0.1°C increments

References: [8 & 9]

Selection & calibration of BI• The organism most resistant to steam heat is the

bacterial spore B. stearothermophilus. This bacterialspore is commonly used BI’s in validating steamsterilization cycles.

• Spore trips or spore suspensions are used in thevalidation studies. the no. of mo’s per ml of suspensionmust be as accurately known as D value.

• Precautions should be taken to use proper storageconditions for B. stearothermophilus BIs .storing in thefreezer provides a more stable resistance profile for theshelf life of the indicator.

References: [7 ]

Heat distribution studiesIt include 2 phases1. Heat distribution in any empty autoclave chamber.2. Heat distribution in a loaded autoclave chamber.a. 10-20 thermocouples should be used/cycle. thermocouples

should be secured inside the chamber.b. The trips where the wires are soldered should not make contact

with the autoclave interior walls or any metal surface.c. 1 end of thermocouple should remain in an ice bath and high

temperature oil bath during each cycle for reference when thetemp monitoring equipement has the capability for electronicallycompensating each temp measurement against an internalreference.

d. Heat distribution studies following the initial study may employfewer thermocouples as the cool spot in the chamber & in theload is identified.

e. The difference in temp b/n the coolest spot $ the mean chambertemperature should not be greater than 2.5C.

References: [8 ]

Heat penetration studies• This is the most critical component of the entire

validation process

• Thermocouples will be placed both inside and outsidethe container at the coolspot location(s) in the steamexhaust line and in constant temperature baths outsidethe chamber

• The sterilization cycle design must be based on theheating charecteristics of the load and containerslocated in the slowest heating zone of the load.

• The effect of load to load variation on the time-temperature profile must also be determined.

• Then the statistically worst case conditions should beused in the final sterilization process design

Validation of dry-heat sterilization cycles

1. Batch oven validation

• Air balance determination in an empty oven data are obtained on the flow rates of both intake and exhaust air. air should be balanced so that positive pressure is exerted to the non sterile side when the door is opend and air velocity across and up and down the opening of the door is ±50 FPM of the average velocity

• Heat distribution in an empty chamber thermocouples should be situated according to a specific predetermined pattern. Repeatability of temp attainment and identification of cold spot can be achieved if the temp range is ±15°C at all monitored locations.

• Heat penetration studies. These studies should be designed to determine the location of slowest heating point within a commodity at various locations of test load in sterilizer.

• Mechanical repeatability. during all these studies mechanical repeatability in terms of air velocity, temp consistency, reliability and sensitivity of all the oven and instrumental controls must be verified.

References: [11 ]

2.Tunnel sterilizer validation Air balance determination• Proper air balance is more critical to a tunnel sterile

process than a batch oven process .since the items being sterilized are exposed to a different air systems(eg:-heating zone $ cooling zone).in the absence of a critical balance of air dynamics, either the items will not be cooled sufficiently once they exit the tunnel or they will be cooled too quickly. causing the glass to shatter and contaminate the entire tunnel area with particles.

• The major problem in validating tunnel sterilizers is the control of particules. not only are items exposed to great extreams in temp, but also the conveyer belt is a natural source of particulates because metal is moving against metal.

• Air must be particulate-free as it enters the tunnel area; therefore, all high efficiency particulate air(HEPA)filters in the tunnel must be tested and certified prior to validation studies.

Heat distribution studies• Thermocouples used in tunnel sterilizer validation

must be sufficiently durable to withstand the extremely high( ≥ 300 c)temperatures in the heating zone area of the tunnel heat-distribution studies should determine where the cold spots are located as a function of the width of the belt $ height of the tunnel chamber. trays or tracks of ampules are vials should run through the tunnel

• Bottle-mapping studies may also be conducted during this phase. the purpose of these studies is to determine possible locations inside the container that are most difficult to heat.

References: [12 ]

Heat penetration studies• For testing of the tunnel sterilization, heat-penetration

studies must be completed in order to identify the coolest container in the entire load. Results of heat-distribution studies should aid in the predicting where the coolest location with in the load should be. Thermocouples should be diposited at or near the coolest point inside the container from bottle-mapping studies.

• The containers inner surface should be in contact with the thermocouple tip because the objective is to sterilize the inner walls of the container, as well as the inner space.

• Every loading should be done using 10-20 thermocouples distributed through out the load.

References: [ 9 ]

Mechanical repeatability

• Air velocity, air particulates, temp consistency and reliability of all the tunnel controls(heat zone temperatures, belt speed, and blower functions)must be proved during the physical validation studies.

References: [ 9 ]

Step by step sequence in the microbial validation of a dry heat process for sterilizing and depyrogenating large volume

glass containers by wegel $ akers et al

1. Place spore carrier in approximately 12 glass bottles located at thecoolest area of the oven. bottles adjucent to the inoculated bottlesshould contain thermocouples for the monitoring purposes .

2. Run a complete cycle using the desired loading pattern for futuredry heat overkill cycles.

3. After the cycle, aseptically transfer the spore strip to vessels ofculture meedia. if spore suspensions were used, aseptically transferthe inoculated bottles to a laminar air flow work station $ addculture media to the bottles. use approximate possitive $ negativecontrols

4. Determine the no. of survivors by plate counting or fractionnegative methods.

References: [11]

Validation of ethylene oxide sterilization cycles

Eto has been a sterilant for over 50 years.

• 5 variables critical to the Eto process. they are

1. Eto concentration

2. Relative humidity

3. Temperature

4. Time

5. Pressure/vaccume.

References: [15]

Procedure for the Eto cycle validation 1. Use a laboratory sized Eto sterilizer during early phases of the

validation process as long as the sterilizer is equipped withdevices allowing variability in vaccume ,relative humidity, temp,gas pressure, timing,$ rate of gassing the chamber.

2. Verify the calibration of all instrumentation involved inmonitoring the Eto cycle.

3. Perform an extensive temp distribution study using an emptysterilizer.

4. Do a series of repetitive runs for each sterilization cycle in anempty vessel in order to verify the accuracy and reliability of thesterilizer contorls and monitoring equipment.

5. Do a series of repetitive heat distribution and heat penetrationruns using a loaded Eto sterilizer.

7.Test should be conducted on the final packaged product.

8.Institute a documented monitoring system primary relying on bio-logical indicators,with lesser reliance on end-product sterility testing.

References: [15]

Validation of radiation sterilization process• The major objective in validating a radiation sterilization

process regardless of whether the mode of radiation iscobalt-60,cesium-137 or electron beam.

• The radiation sterilization cycles are validated based uponthe achievement of sterility ,many factors must beconsidered in the utilization and approval of the radiationsterilization process. such factors include

The physical appearance of the container system and itscontents,

Stability of the active ingradient, if present, and Safety of the irradiated material.

References: [16]