Process Validation Strategy

A written program should be established and followed for validating the manufacturing processes for all APIs. Validation studies should ensure that a specific manufacturing process is capable of performing in a reliable and consistent manner and results in a homogeneous API that consistently meets predetermined specifications.

Validation should embrace steps in the processing of APIs that are critical to the quality and purity of the final API, and should include: - Definition of the API in terms of its critical quality attributes. Among the attributes that should be considered are chemical purity; qualitative and quantitative impurity profiles; physical characteristics such as particle size, bulk and tap density; polymorphic forms; moisture and solvent content; homogeneity; and microbial quality (if the product is susceptible to microbial contamination).

- Identification of process parameters that could affect the critical quality attributes of the API. Critical parameters should be determined by scientific judgement and typically should be based on knowledge derived from research, scale-up batches, or manufacturing experiences.

- Determination of the range for each critical process parameter expected to be used during routine manufacturing and process control. Data to substantiate the ranges for critical process parameters generally should be obtained from laboratory- or pilot-scale batches, unless a specific parameter can only be determined from a production-scale batch.

Examples of processing steps that could be defined by the API manufacturer as critical include: - Phase changes, such as dissolution or crystallization; - Phase separation, such as filtration or centrifugation; - Steps that cause chemical changes; - Steps that alter temperature or pH; - Mixing of multiple raw materials; and - Steps that cause changes in surface area, particle size, bulk and tap density or homogeneity.

Critical process parameters (e.g., reaction times, reaction temperatures, reactant ratios, concentrations, pressures, pH, and impurity levels) should be controlled and monitored during process validation studies. Process parameters unrelated to quality, such as variables controlled to minimize energy consumption or equipment use, need not be included in the process validation.

Process validation should confirm that the impurity profile for each API is within the limits specified and is comparable to the profile determined during process development or for batches used for pivotal/toxicological studies.

Retrospective Validation

Retrospective validation could be conducted for a well-established process that has been used without significant changes (e.g., changes in raw materials, equipment, systems, facilities, or in the production process) that affect the critical quality attributes of the API. This validation approach should be used only when there is sufficient history on past API batches to demonstrate the process consistently produces acceptable products, and where: - Critical quality attributes and critical process parameters have been identified and documented; - Appropriate in-process specifications and controls have been established and documented; - There have not been excessive process/product failures attributable to causes other than operator error or equipment failure unrelated to equipment suitability; and - Impurity profiles have been established for the existing API.

In addition to the information described in Section XIII.B., the validation protocol should include the batch selection criteria and analytical data that will be evaluated to determine consistency of the process.

The number of batches to review will depend on the process, but, in general, data from 10 to 30 consecutive batches should be examined to assess process consistency. The review should include any batches that failed to meet specifications. All batches within the selected review period should have been manufactured by the same process and have the same documented history of controls and tests as current APIs. Additional testing of retained samples may be warranted to obtain the necessary data to retrospectively validate the process.

Data obtained should be evaluated by appropriate personnel, and a final validation report summarizing the results and appropriate conclusion should be prepared. This report should be reviewed and approved by the organizational units that approved the original protocol.

Retrospective validation could also be employed to provide additional data to supplement prospective validation and either build confidence in a particular manufacturing process or impugn it as test results are received.

What is Validation?

Validation Master Plan. A Validation Master Plan (VMP) is an integral part of a well organized validation project. It documents the company's approach to complex validation projects. The VMP has a broad scope. It clarifies responsibilities, general objectives, procedures to be followed for validation, and it prioritizes multiple validation tasks. It may reference several protocols and procedures to be written in order to conduct the qualification of several different pieces of equipment and different processes. It may also specify schedules for validation and the allocation of resources needed to perform the validation. Your VMP provides a means of communication to everyone associated with the project. It lets management know how the company’s resources are being allocated and when they will see the results. It tells the validation team what they have to do, when they have to do it, and gives them a means of tracking progress. Other groups can find out what the validation team is doing and what their roles are in support of the validation project. FDA can look at the VMP and realize that the validation project is well thought out and organized; that there is a logical reason for including or excluding every system from the validation project based on a risk analysis. VCI’s experience at writing Validation Master Plans can make your project go smoother whether it’s a new, greenfield plant, expansion of an existing facility, or a rearrangement of operating equipment. Click here to read “The Validation Master Plan: How to Write It and How to Make It Work for Your Company “ by Dr. Norm Howe, VCI Senior Partner, and Kristi Musgrave, VCI Senior Validation Engineer.

Process validation. The FDA defines process validation as "establishing documented evidence which provides a high degree of assurance that a specific process will consistently produce a product meeting its pre-determined specifications and quality attributes." Process validation is a requirement of the current Good Manufacturing Practices Regulations for Finished Pharmaceuticals (21 CFR Parts 210 and 211), Active Pharmaceutical Ingredients (ICH Q7A), and for Medical Devices (21 CFR Part 820). Validation is sometimes mistakenly viewed as a separate component that is squeezed into a gap between mechanical completion and the startup of a project. In fact it should be incorporated into the planning of the project from the outset and systems need to be in place which insure that the process will remain in compliance throughout the lifetime of the plant.

As outlined in the Commissioning and Qualification Baseline Guide of the International Society of Pharmaceutical Engineers a new project should start with a set of User Requirement Specifications (URS). These tell what the new installation is supposed to do. The URS’s should be carefully documented so that any changes can be tracked through the life of the project. A traceability matrix is a common way to accomplish the tracking of changes in User Requirement Specifications. From the URS the designers formulate a Functional Requirement Specification (FRS) which documents how the new installation is supposed to work. After review of the FRS a detail design is developed and the project is built.

Qualifications must follow an approved protocol that includes acceptable ranges and details what will happen if the tested parameters fall outside acceptable limits. There is a good reason for this. Hard experience has shown that decisions made at 3 o’clock in the morning over a recalcitrant pump can be suboptimal. When the protocol is written and approved in the calm before the storm of plant start-up, there is less of a chance that the response to an out-of-range result will be, ‘Get a bigger wrench.’

Whether your next validation project is large or small VCI can guide you through to a successful conclusion.

Process Characterization. Before validating a process you must first characterize it. You start by defining the boundaries of the process. But the most important part is to truly understand your technology. What are the Critical Process Parameters, ie., the inputs that really determine product quality? Much of this understanding can come from your process development work and it is given to you in the design transfer documents. However, a complete understanding of the process can come only with your production equipment.

Computer and Automated Controls Validation. Prequalification. A new project should start with a set of User Requirement Specifications (URS). These tell what the new installation is supposed to do. The URS’s should be carefully documented so that any changes can be tracked through the life of the project. A traceability matrix is a common way to accomplish the tracking of changes in User Requirement Specifications. For large automation projects like Distributed Control Systems the URS should be a separate document. For imbedded Programmable Logic Controllers it should be incorporated into the equipment URS. A loop list is generated and data backup systems are defined at this point in time. From the URS the designers formulate a Functional Requirement Specification (FRS) which documents how the new installation is supposed to work. It summarizes all activities the software will perform and should include early definitions of inputs, outputs, calculations and applications. The selection of the control system is documented. After review of the FRS a detail design is developed including loop diagrams and the IQ/OQ test plan.

21 CFR Part 11, Electronic Signatures/Electronic Records. Part 11 provides criteria for acceptance of electronic records and signatures by FDA. It allows the use of a wide array of electronic technology. Although much confusion surrounds 21 CFR Part 11 it is in one way quite simple. Conceptually FDA wants the same security, traceability, and many other capabilities that are inherent in a paper system. For instance, if an error is discovered on a paper document we would draw a single line through the offending entry, note the correction, sign it, date it, and note down the reason for the error. FDA wants the same assurance with electronic systems. That means that the old file cannot be overwritten with the corrected data. Electronic records and electronic signatures must have the same integrity and reliability as paper records and handwritten signatures.

To what electronic data does 21 CFR Part 11 apply? Part 11 applies to all electronic records and signatures that are created, maintained, archived, retrieved, or transmitted that fall under any FDA records requirements in the Food, Drug, and Cosmetic Act, the Public Health Service Act, or the Code of Federal Regulations Title 21. These regulations are known as the Predicate Rules of which the following are of most interest for validation: Finished Pharmaceuticals (21 CFR Parts 210 and 211), Active Pharmaceutical Ingredients (ICH Q7A), and for Medical Devices (21 CFR Part 820). The predicate rules mandate what records must be maintained; the content of records; whether signatures are required; how long records must be maintained, etc. If there is no FDA requirement that a particular record be created or retained, then 21 CFR Part 11 most likely does not apply to the record. VCI can help you determine which of your computer systems are subject to 21CFR Part 11.

Part 11 regulations require controls for audit trails, system operational checks, system authority checks, metadata, and system device checks.

What is 'metadata'? It is 'data about data'. The types of metadata that can be associated with an electronic record may include: details of the record's creation, author, creation date, ownership, searchable keywords, details of the type of data found in the document, and the relationships between different data components. Metadata must be stored as an integral part of the electronic document it describes. More useful information at http://www.21cfrpart11.com/

Laboratory Validation / Analytical Method Validation. Laboratory Validation is a process that is employed to ensure that laboratory test data and results are consistent, accurate and precise. The validation process for test methods, as well as the instrumentation that is used to perform the analysis, have IQ, OQ and PQ protocols. There are eleven main principles to the PQ laboratory test validation protocol. These points are to be applied to each and every laboratory test that is critical to the pharmaceutical manufacturing process as well as the stability program and any process validation. Not all of the eleven principles may apply to each type of testing that is performed, however, a thorough review must be done in order to ensure a complete protocol has been written. VCI's experience with a broad range of analytical methods can make your laboratory validation project run flawlessly.
The eleven PQ principles are listed below:

• Specificity
• Linearity
• Accuracy
• Precision
• Robustness
• Range
• Detection Limit (LOD)
• Quantitation Limit (LOQ)
• Ruggedness
• Selectivity
• System Suitability

Cleaning Validation. This validation is used to show proof that the cleaning system consistently performs as expected and provides scientific data that consistently meets pre-determined specifications for the residuals.

The cleaning validation process must be written into protocols and standard operating procedures which are detailed and specific for the different pieces of equipment and instrumentation used by the facility for each type of drug product produced. Other protocols and SOP's are also required if cleaning is performed based on the type of product manufactured or process used (such as a batch or bulk process or shared versus dedicated equipment).

A final report on the cleaning validation system will attest that the studies and data prove that the process is in control and cleans as expected. This report will also detail when and why revalidation needs to take place. Call on VCI to help you clean up your cleaning validation backlog.

Hazard Analysis and Critical Control Points (HACCP). The HACCP process is a prevention-based food safety system. These HACCP programs are to be designed to prevent the occurrence of potential food safety problems. The system appears to be simple at first glance, however, it requires a methodical, systematic approach. A pre-requisite to a well-developed and implemented HACCP system must be a solid current Good Manufacturing Practices (cGMP) program as well as strongly committed management.

The key to the success of your HACCP program is to have your employees trained and educated on the reasons behind your HACCP plan as well as in current Good Manufacturing Practices (cGMP). Training must also be provided to your employees and management on the importance of food safety and how it applies to them. It will be essential that the unique systems of your plant and facility be considered by your HACCP team and expressed to the plant personnel.
Call VCI at 734-274-4680 to get immediate help with your HACCP plan or email us at Ask VCI to find out how VCI can help you.

Validation of Analytical Assays and Test Methods for the Pharmaceutical Laboratory

By Robert V. Sarrio and Loui J. Silvestri, PhD
AccuReg

Overview

Analytical procedures used to measure the quality of pharmaceutical products span almost the entire range of currentlyavailable technologies and techniques. From immunoassay and electrophoretic techniques used to characterize protein moeities, and chromatographic and potentiometric methods used to evaluate the qualities of small molecules, the variety of procedures (and approaches necessary to prove these methods' validity and usefulness) can be overwhelming. However, when evaluating available procedures to determine which are best for your intended use, it is important to keep in mind that the most important aspect of any analytical method is the quality of the data it ultimately produces.

Perhaps the most useful and widely-consulted guidance in the industry is the USP's General Chapter 1225entitled, "Validation of Compendial Methods". This Chapter opens by referencing the Federal Food, Drug and Cosmetics Act (and hence, stressing the legal status of USP test procedures), then continues with a formal definition of "validation" as it applies to analytical methods. Directly quoted, the Chapter states that "Validation of an analytical method is the process by which it is established, by laboratory studies, that the performance characteristics of the method meet the requirements for the intended analytical applications."

The most significant point raised by this definition is that the validity of a method can be demonstrated only through laboratory studies. It is not sufficient to simply review historical results; instead, laboratory studies must be conducted which are intended to validate the specific method, and those studies should be pre-planned and described in a suitable protocol. The protocol should clearly indicate the method's intended use and principles of operation, as well as the validation parameters to be studied, and a rationale for why this method and these parameters were chosen. The protocol also must include pre-defined acceptance criteria and a description of the analytical procedure, written with sufficient detail to enable persons "skilled in the art" to replicate the procedure.

Validation Parameters - Assays

USP General Chapter 1225, as well as the ICH Guideline for Industry (Text on Analytical Procedures), provide cursory descriptions of typical validation parameters, how they are determined, and which subset of each parameter is required to demonstrate validity, based on the method's intended use. For example, it would be inappropriate to determine limits of detection or quantitation for an active ingredient using an assay method intended for finished product release. However, if the method was intended to detect trace quantities of the active ingredient for purposes of a cleaning validation study, then knowledge of the detection and quantification limits are appropriate and necessary. For this reason, validation of each assay or test method should be performed on a case-by-case basis, to ensure that the parameters are appropriate for the method's intended use. This is even more important when validating stability-indicating assay methods, because these validations are more complex - for example, they may require forced degradation, samples spiked with known degradates, literature searches, etc.

The following definitions, taken from the ICH Guideline for Industry (Text on Analytical Procedures), will provide a background for subsequent discussion:

Analytical Procedure.

The analytical procedure refers to the way of performing the analysis. It should describe in detail the steps necessary to perform each analytical test. This may include, but is not limited to, the sample, the reference standard and the reagents preparations, use of the apparatus, generation of the calibration curve, use of the formulae for the calculation, etc.

Specificity.

Specificity is the ability to assess unequivocally the analyte in the presence of components which may be expected to be present. Typically, these might include impurities, degradants, matrix, etc. Lack of specificity of an individual analytical procedure may be compensated by other supporting analytical procedure(s).

This definition has the following implications:

• IDENTIFICATION: To ensure the identity of an analyte.
• PURITY TESTS: To ensure that all the analytical procedures performed allow an accurate statement of the content of impurities of an analyte, i.e., related substances test, heavy metals, residual solvents content, etc.
• ASSAY (Content or Potency): To provide an exact result which allows an accurate statement on the content or potency of the analyte in a sample.

Accuracy.

The closeness of agreement between the value which is accepted either as a conventional true value or an accepted reference value, and the value found.

Note: When measuring accuracy, it is important to spike placebo preparations with varying amounts of active ingredient(s). If a placebo cannot be obtained, then a sample should be spiked at varying levels. In both cases, acceptable recovery must be demonstrated.

Precision.

The precision of an analytical procedure expresses the closeness of agreement (degree of scatter) between a series of measurements obtained from multiple sampling of the homogeneous sample under the prescribed conditions. Precision may be considered at three levels: repeatability, intermediate precision and reproducibility.

Precision should be investigated using homogeneous, authentic (full scale) samples. However, if it is not possible to obtain a full-scale sample it may be investigated using a pilot-scale or bench-top scale sample or sample solution.

The precision of an analytical procedure is usually expressed as the variance, standard deviation or coefficient of variation of a series of measurements. Refer to this month's "The Regulatory Clinic" for a discussion of AccuReg's consensual interpretations of the following terms that express precision:

a. Repeatability. Repeatability expresses the precision under the same operating conditions over a short interval of time. Repeatability is also termed intra-assay precision.

b. Intermediate Precision. Intermediate precision expresses within-laboratories variations: different days, different analysts, different equipment, etc.

c. Reproducibility. Reproducibility expresses the precision between laboratories (collaborative studies usually applied to standardization of methodology).

Detection Limit.

The detection limit of an individual analytical procedure is the lowest amount of analyte in a sample which can be detected but not necessarily quantitated as an exact value.

Quantitation Limit.

The quantitation limit of an individual analytical procedure is the lowest amount of analyte in a sample which can be quantitatively determined with suitable precision and accuracy. The quantitation limit is a parameter of quantitative assays for low levels of compounds in sample matrices, and is used particularly for the determination of impurities and/or degradation products.

Linearity.

The linearity of an analytical procedure is its ability (within a given range) to obtain test results which are directly proportional to the concentration (amount) of analyte in the sample.

Note: Measurements using clean standard preparations should be performed to demonstrate detector linearity, while method linearity should be determined concurrently during the accuracy study. Classical linearity acceptance criteria are 1) that the correlation coefficient of the linear regression line is not more than some number close to 1, and 2) that the y-intercept should not differ significantly from zero.

When linear regression analyses are performed, it is important not to force the origin as (0,0) in the calculation. This practice may significantly skew the actual best-fit slope through the physical range of use.

Range.

The range of an analytical procedure is the interval between the upper and lower concentration (amounts) of analyte in the sample (including these concentrations) for which it has been demonstrated that the analytical procedure has a suitable level of precision, accuracy and linearity.

Robustness.

The robustness of an analytical procedure is a measure of its capacity to remain unaffected by small, but deliberate, variations in method parameters and provides an indication of its reliability during normal usage.

Note: Ideally, robustness should be explored during the development of the assay method. By far the most efficient way to do this is though the use of a designed experiment. Such experimental designs might include a Plackett-Burman matrix approach to investigate first order effects, or a 2k factorial design that will provide information regarding the first (main) and higher order (interaction) effects.

In carrying out such a design, one must first identify variables in the method that may be expected to influence the result. For instance, consider an HPLC assay which uses an ion-pairing reagent. One might investigate: sample sonication or mixing time; mobile phase organic solvent constituency; mobile phase pH; column temperature; injection volume; flow rate; modifier concentration; concentration of ion-pairing reagent; etc. It is through this sort of a development study that variables with the greatest effects on results may be determined in a minimal number of experiments.

The actual method validation will ensure that the final, chosen ranges are robust.

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Other points to consider include:

System Suitability

In addition, prior to the start of laboratory studies to demonstrate method validity, some type of system suitability must be done to demonstrate that the analytical system is performing properly. Examples include: replicate injections of a standard preparation for HPLC and GC methods; standardization of a volumetric solution followed by assays using the same buret for titrimetric methods; replicate scanning of the same standard preparation during UV-VIS assays, etc. When the method in question utilizes an automated system such as a chromatograph or an atomic absorption spectrophotometer, a suitable standard preparation should be intermittently measured during the sample analysis run. The responses generated by the standard should exhibit a reasonable relative standard deviation. This is done primarily to demonstrate the stability of the system during sample measurements. System suitability for dissolution studies should be performed using both USP non-disintegrating and disintegrating tablets prior to the validation of dissolution methods.

Validity Checks - General Tests

It is important to realize that assays are not the only tests important in evaluating the qualities of a drug product. The USP contains numerous identity tests of a chemical nature. In these types of tests, one should treat a placebo preparation with the reaction reagent to ensure a negative result is achieved. Otherwise, the test has no meaning. Dissolution tests, for instance, should be evaluated for adequate sink conditions (i.e., adequate solubility in an adequate volume of the dissolution media) prior to development.

Protocols

As mentioned earlier, prior to initiating a validation study, a well-planned validation protocol should be written and reviewed for scientific soundness and completeness by qualified individuals. The protocol should describe the procedure in detail, and should include pre-defined acceptance criteria and pre-defined statistical methods. Following approved by the appropriate corporate and Quality Control authorities, the protocol should be executed in a timely manner. A typical assay validation will require the preparation of product placebo(s), standards, and many samples.

How many times should an assay be repeated to ensure "validity"? Although 3 sequential replicates are often considered the "magic number," a far more definitive number is one produced by a sound scientific rationale, usually with the assistance of statistical analyses.

Subsequent to the execution of the protocol, the data must be analyzed with results, conclusions and deviations presented in an official validation summary report. Provided the pre-defined acceptance criteria are met, and the deviations (if any) do not affect the scientific interpretation of the data, the method can be considered valid. A statement of the method's validity should be placed at the beginning of the final summary report, along with the signatures and titles of all significant participants and reviewers.

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In the final analysis, the purpose of validating methods is to ensure the procurement of high quality data. After all, if the quality of data is questionable, no meaningful conclusions can be reached about the quality of the product - which will have seriously detrimental affects on stability study data reviews, process validation data reviews, and annual batch reviews, to name a few. Time invested in validating analytical methods in the beginning pays big dividends in the long run.

Validation of methods for the sterilization of tubing

A variety of methods are routinely used to monitor & validate sterilization protocols used in the production of sterile products.

Sterilisation protocols include steam, dry heat, ethylene oxide, hydrogen peroxide vapour and gamma irradiation have been developed to deal with the diverse range of materials now used for the preparation and storage of sterile products.

Steam sterilization is routinely carried out at 121°C or 135°C and is used predominantly for sterilisation of paper & fabric wrapped products, bottles liquids, glass & stainless steel equipment. Dry heat sterilization at 180°C is suitable for stainless steel equipment but not for plastics or liquid-containing products. Ethylene oxide and gamma irradiation are ideal for treatment of bulky packs and paper or plastic products which may be sensitive to heat and cannot be sterilized with steam or dry heat. More recently hydrogen peroxide vapour has proved well suited suited to the sterilization of isolator cabinets used in the production and packaging of many pharmaceutical products.

Chemical indicators which give an irreversible colour change are used to provide a visible indication of exposure to a sterilization cycle - the indicators themselves however do not provide a realistic demonstration of cycle lethality. but simply show that the product has been exposed to conditions expected to lead to sterilization. In order to demonstrate sterilization cycle lethality it is necessary to use a biological indicator, (BI).

A biological indicator (BI) is a device containing a known population of a viable organism exhibiting a significant and quantified resistance to the sterilization conditions to be validated.

The challenge organism is usually selected to offer a significantly greater resistance than the organisms normally encountered in order to provide the greatest level of confidence in the procedure. The spores from spore forming bacteria are ideally suited to use as indicator organisms - the organism selected according to the type of sterilization protocol to be tested:

Geobacillus stearothermophilus ATCC 7953 for steam
Bacillus atrophaeus ATCC 9372 for dry heat & ethylene oxide
Bacillus pumilus ATCC 27142 for gamma irradiation
Geobacillus stearothermophilus ATCC 12980 for hydrogen peroxide

Biological indicators exist in a variety of formats designed to facilitate handling, ease of use and to ensure they remain free from post-cycle contamination. Spores can be presented on a variety of carriers (paper strip, stainless steel, cotton thread, stainless steel disc or wire) each individually packaged in glassine or Tyvek envelopes.

After exposure to the sterilization cycle they must be transferred aseptically to individual tubes of Tyryptone soy broth (TSB) for incubation in order to check for presence of viable spores. Self-contained indicators Pro Spore and Pro Spore 2 ampoules) containing both spores and recovery medium have been developed to remove the requirement for aseptic transfer following the sterilization cycle thus making the technique quicker and simpler to carry out and reducing the need to make the transfer under laboratory conditions. .

Validation of sterilization cycles is relatively straight forward for loads comprised of bottles, flasks, tubes, cloth packs etc. where the introduction of BI's into the load at various locations, (centre load, close to drain point etc.) may be accomplished quickly and without problem. Validation of more complex items of equipment (fermenter vessels, filtration sets etc.) may however prove much more difficult due to the complex geometry & bulk of the equipment itself and the restricted access to any entry & exit tubing attached to it.

Tubing has always presented a particularly difficult challenge for process validation, requiring the placement of a BI at the centre point of the tubing run. The positioning and recovery of the indicators is labour intensive and fraught with potential problems Care must be taken when positioning indicators to avoid occluding the tube bore thus preventing easy steam or gas access - any restriction in gas flow may itself contribute to failure of the BI & require lengthy investigation and further test re-validation.

A novel development by Raven Biological Laboratories Inc of Omaha now allows tubing validation to be made as simply and quickly as routine load validation using spore strips.
ProLine, is an in-line Process Challenge Device designed specifically to assist in validating the sterilization of various lengths and diameters of tubing. Available with either B.atrophaeus or G.stearothermophilus ATCC 7953 spores ProLine can be used to validate either ethylene oxide or steam or sterilization cycles with tubing ranging in diameter from 1/8" to 5/8" ID.

Inside the two conical halves of the ProLine device, a paper disc impregnated with bacterial spores is packaged in a glassine pouch and sandwiched between two sets of "O" rings to form a gas-tight seal. The length of tubing to be validated is cut in half and the ProLine device used to attach the two pieces together. The sterilant (steam or Ethylene oxide) must enter both ends of the tubing and penetrate to the mid-point of the tubing where the spore disc is housed within the ProLine device.

When the sterilization cycle is completed, the ProLine and attached lengths of tubing are removed from the sterilizer chamber and transferred to an area where an aseptic transfer of the spore disc to TSB can be carried out. This is accomplished by breaking the two section of the ProLine device apart ( Insert figures 2 and 3) to expose the glassine packaged spore disc. The glassine envelope can be handled without fear of contaminating the exposed spore disc within. The envelope can then be opened aseptically and the spore disc transferred to TSB for incubation (7 days) in order to develop the test result.

Results for validation of steam sterilization using Pro Spore 2 self contained indicators or Raven G.stearothermophilus ATCC 7953 spore strips and modified TSB with Bromocresol Purple indicator are available in only 24 hours. These products and BI combinations have been demonstrated to give reliable and accurate detection of spores surviving the sterilization cycle - A clearly visible colour change from purple to yellow along with turbidity in the broth signals germination and growth of the spores and a failure of the cycle to inactivate the BI.

For further details of the full range of BI's available for sterilizer validation visit the web site at www.m-techmicro.com or contact M-Tech Diagnostics Ltd. directly on Free phone 08-0800-68324 (08-0800-MTECH)