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Fundamental validation skills related to heating, ventilation, and air conditioning must be thoroughly understood. Knowing the early history and development of validation is essential to understand the current set of regulations and standards governing the industry. This article reviews the history and outcome of contamination in large-volume parenteral drug products and discusses the qualification requirements of modern HVAC systems.
The year 2006 marked the 30th anniversary of the formal introduction of process validation concepts and requirements by the US Food and Drug Administration. Despite more than 30 years of common usage, only recently have the theory and practice of validation become fully developed and widely understood, although many misconceptions remain.
Origins of validation
The concept and practice of pharmaceutical validation first became law in June 1963 with the publication of good manufacturing practice (GMP) regulations. Before that, there was no requirement to validate production processes. Product quality was presumably ensured by collecting and analyzing drug samples. Despite the law, there remained little inspectional focus on process validation. This changed, however, when a nationwide epidemic of septicemia occurred that was caused by contaminated intravenous fluids (large-volume parenterals, LVPs). Between July 1970 and April 1971 in many hospitals in the United States, there were outbreaks of nosocomial (hospital acquired) septicemia caused by Enterobacter cloacae or E. agglomerans. All of these hospitals used infusion products made by one manufacturer, and all affected patients had onset of septicemia while receiving the company's infusion products.
Milestone. 30 Years of Pharmaceutical Technology
Septicemia was epidemiologically and microbiologically traced to intrinsic contamination of the company's screw-cap closure for infusion bottles, which were sealed with a newly introduced elastomer liner. Investigations in the laboratory and in the manufacturing plant into the mechanism of contamination of these products revealed the following:
Figure 1: Newer HVAC designs feature variable frequency drives (VFDs). VFDs are replacing variable inlet vanes on fan scrolls as the method for air-volume and pressurization control. They alter the frequency of the electrical supply to fan motors. As duct static pressure or air volume varies from setpoint, the VFD slows or increases motor speed proportionately. Modulation of fan motor speed reduces energy consumption. Fans that use variable inlet vanes for control purposes always operate at 100% rated motor speed. Pressure and air volume control are also better when VFDs are used (6). (PHOTO COURTESY OF ABB, LOW VOLTAGE DRIVES)
Nine deaths were initially attributed to this outbreak. Further analysis estimated that between 2000 and 8000 cases had actually occurred. Not all cases ended with the death of a patient. Nonetheless, nearly 10% of the case patients in the studied hospitals died while bacteremic or shortly thereafter (2).
On closer examination, FDA, the Centers for Disease Control and Prevention (CDC), and company officials discovered several manufacturing problems. Although component bioburden (bottles, caps, etc.) was acceptable pre- and poststerilization, product cooling and additional downstream processing were identified as the sources of contamination. Sterilizer cooling water was considered a possible source of contaminants. Water for bottle cooling was obtained from a municipal source, and chlorine content was frequently below that required for bacteriostasis. As bottles continued to cool after removal from the sterilizer, ambient air and moisture infiltrated through the bottle threads and into the cap liner. Disassembly and testing of cap inner components later demonstrated that environmental contaminants, including the epidemic organisms, were distributed within the caps. Bottle breakage was commonplace after sterilization, and dextrose solutions were spilled onto floors below conveyors and related equipment. Spillage actively promoted the growth of the epidemic organisms, creating a high bioburden in critical processing areas (1).
Milestone. 30 Years of Pharmaceutical Technology
In late 1971, FDA began an intensive review and evaluation of LVP production because of justified concerns that not all manufacturers could ensure the level of microbiological quality required for LVP drug products. This review was first limited to specific, individual manufacturing or container-closure problems. In 1973, the review expanded to include extensive sampling of LVP products, comprehensive facility inspections, and detailed discussions between the industry and FDA (3).
In March 1973, another outbreak of LVP-attributed septicemia occurred, this time associated with a different manufacturer and a different product (5% dextrose in lactated ringers or D5LR). A hospital in Milwaukee reported three cases of septicemia that developed within three hours from the start of infusion. Hospital officials suspected that each 1-L bottle of D5LR used was intrinsically contaminated. One patient died as a consequence of their intravenous therapy, and another fell critically ill. Later, CDC learned of two additional cases of septicemia caused by contaminated D5LR, one at another Wisconsin hospital and one in Ohio. The manufacturer recalled more than six lots of contaminated product. The recalled infusion was prepared by a newly modified process which included exposure of the bottles to increased pressure during the autoclave cycle (4).
Milestone. 30 Years of Pharmaceutical Technology
Concerned with the ongoing problems in the LVP industry, FDA issued a draft proposal in February 1974 that defined requirements and specifications for LVP manufacturing and processing. This was followed with the publication of a draft section to the Code of Federal Regulations, Part 212, "Current Good Manufacturing Practice in the Manufacture, Processing, Packing, or Holding of Large Volume Parenterals for Human Use," on June 1, 1976. This was the first time FDA had issued well-defined process standards for drug products, and although these standards had been discussed with industry in advance, many manufacturers objected to the limitations now being placed on LVP manufacturing and the obstacles to innovation (3). Consequently, the draft LVP regulations and proposed regulations for small-volume parenterals were withdrawn by the agency, although many of the concepts, particularly validation, were voluntarily applied by industry nonetheless.
So began the start and evolution of validation practices and technologies to the seemingly complex set of rules and guidelines used by industry today. Publications of the late 1970s and early 1980s, particularly those of the Parenteral Drug Association (PDA), introduced the concept of qualification and validation to the industry at large. Companies began to qualify and validate their sterilization processes initially, and then applied these same validation principles to other systems. With FDA's 1987 Guideline on General Principles of Process Validation, the validation of equipment, systems and processes became widespread and mandatory as manufacturers of all drug types were alerted to FDA's expectations for process validation (5).
One example of this validation process is the qualification and validation of heating, ventilating, and air conditioning (HVAC), which is universal in the industry. The importance of HVAC to product quality and safety cannot be minimized. This important concept was not lost on FDA, which should be evident for anyone who reads these dated but insightful regulations.
HVAC system qualification and validation
The procedures for HVAC validation are now commonly understood. HVAC system validation is always based on design. Engineers and owners design systems, and validation specialists interpret these designs and reduce this information in the form of protocols. Quality assurance professionals and regulatory authorities review the designs at various stages of development to ensure compliance with GMP regulations and appropriate industry standards (7).
The standard sequence for HVAC system validation is installation (IQ), operational (OQ), and performance qualification (PQ). To ensure regulatory compliance, design review begins when drawings and specifications are approximately 35% complete, but always before long lead-time equipment is ordered from vendors (7). Rarely are serious errors or omissions noted during review of HVAC designs, because design criteria are understood by reputable engineers and engineering companies designing these systems.
In nearly all pharmaceutical facilities, multiple air handlers exist, each designed to support a specific zone within the building. Each zone is exhausted by one or more exhaust fans interlocked with the air-handling unit (AHU), and depending on design, return fans also. IQ and OQ protocol boundaries should be set that encompass one AHU and the interlocked return and exhaust fans only. HVAC zones do not operate in isolation but are influenced and controlled by conditions in adjacent zones. This is an important consideration when confirming room pressurizations and air-flow directions during OQ.
Information for validation purposes must be carefully selected from approved HVAC design documents. Drawing sets and specifications literally contain thousands of field-verifiable design elements. The validation process must provide a high degree of assurance, not absolute assurance, that the HVAC system was installed and performs according to design. Validation testing is not and cannot be exhaustive. Equipment inspections, test durations, sampling frequency, etc., must be carefully chosen to provide the high degree of assurance stated previously, while avoiding over testing. If proposed testing and inspections are not meaningful, or if the cost/benefit or cost/risk ratios are high, the testing or inspection should be reconsidered. If there is no regulatory requirement and if testing appears meaningless or costly, the test or verification should be omitted.
Installation qualification. Airflow drawings (AFDs) are the most useful of all HVAC design documents, and certainly fundamental to IQ. AFDs provide the system layout in schematic detail, and each drawing is often limited to a single AHU and associated ductwork, instrumentation, dampers and exhaust fans. AFDs are not drawn to scale, and systems cannot be built entirely using AFDs. This is the purpose of duct drawings. AFDs are basic in that they identify system-critical components that must be inspected during IQ. Critical items are those where a tag number is usually assigned: these include AHU , exhaust fan, humidifier, air monitoring device, reheat coil, and so forth.
An IQ protocol must be prepared for documenting the results of system inspection. Protocols should be designed to record data into tables in protocols, with one table reserved for each major component (AHU, exhaust fan, etc.). A tabular protocol format ensures the appropriate comparison between design (specified condition) and system installation (actual condition) is performed. The validation engineer or specialist should inspect system components while construction and installation are in progress for the following reasons:
Operational qualification. HVAC system OQ begins after system IQ is completed. Outstanding items from IQ may remain open, but provided these are limited in number and do not affect system operation, OQ may proceed. It is important to resolve IQ punchlist items and deviations promptly and to explain the circumstances of each in the IQ Summary Report.
It is advisable to perform HVAC OQ concurrent with system commissioning. Recent changes in the pharmaceutical industry have placed added emphasis on commissioning to reduce validation costs and to accelerate project schedules. More owners and facility managers are using independent commissioning agents to commission HVAC and similar mechanical systems. It is the responsibility of the validation team to interface early with the commissioning agent to benefit from the synergy between commissioning and qualification. Because commissioning is a noncompliant activity, the standards for documentation and control are less formalized. Commissioning affords the opportunity to debug and troubleshoot the system while avoiding some of the deviation reporting commonplace in validation. When properly commissioned, HVAC systems are turned over to the owner free of common operational defects that complicate OQ and PQ.
Airflow diagrams play an important part in HVAC system OQ because airflow directions, air volumes, and room pressurizations are commonly indicated on these drawings. AFDs often contain operational sequences in their margins. These sequences become the basis for system functional testing as well as an important part of the functional requirement specifications for the corresponding building management system.
As a noncompliant activity, commissioning does not include all typical HVAC system OQ tests and verifications. Nonetheless, HVAC OQ protocols must contain the following testing and documentation requirements at a minimum:
Performance qualification. HVAC system PQ begins only after OQ has been completed successfully. Because airborne viable and nonviable particulate levels, room bioburden, and temperature/relative humidity control rely on a system operating as designed, the transition to PQ must occur only after OQ is complete and all deviations are resolved.
Like IQ and OQ, the test procedures for HVAC system PQ are now well defined. Standard PQ acceptance criteria are published by organizations such as the European Commission (EC), International Organization for Standardization (ISO), and FDA.
Currently, the definitive standard for multinational companies is the EC Guide to Good Manufacturing Practice, Revision to Annex 1, Manufacture of Sterile Medicinal Products (9). This document provides supplementary guidance on the principles and guidelines of GMP as applicable to sterile products such as LVPs. One section in Annex 1 is specific to clean environments used for aseptic manufacturing. Annex 1 divides manufacturing areas into letter grades (A, B, C, D) that closely correspond to the older Class 100, 10,000, and 100,000 conditions contained in Federal Standard 109 (now cancelled). One notable difference from previous standards is that air-sampling volumes have now increased to 1 m3, a change from the historical 1-ft3 sample size specified in the LVPs. As expected, upward adjustments have been made to particle limits because air-sample volumes have now increased by approximately 35 times.
ISO 14644-1, "Cleanrooms and Associated Controlled Environments—Part 1: Classification of Air Cleanliness," should be consulted when qualifying HVAC systems other than those supporting aseptic production. ISO 14664-1 assigns nine particulate classifications to manufacturing areas, with Class 1 the most demanding and Class 9 the least restrictive (10). ISO classes 5–9 are appropriate for all pharmaceutical facilities. In solid-dosage facilities where airborne dusts are expected, it often makes little sense to monitor particulate levels while operations are in progress. However, baseline (static) information is often useful, as this may provide a sign of HEPA filter failure or other indication of unwanted particulation.
The proposed LVP regulations required that air microbial quality be monitored in both critical and noncritical areas, although this was not accepted practice at the time. Allowable microbial levels or the types of organisms permitted were not specified because little historical data were available to FDA. In time, however, voluntary standards and guidance documents appeared that manufacturers agreed to comply with. Both the United States Pharmacopeia and EC Guide to Good Manufacturing Practice provide recommended microbial standards that many manufacturers observe, although these standards are not legally enforceable. With proper HVAC design and construction, room finish selections, disinfection procedures, and personnel gowning, there are few difficulties attaining and then maintaining these standards.
For all particulate-controlled areas in most types of facilities, both nonviable and viable airborne particulate monitoring must be performed. PQ testing also must include the enumeration of surface bioburden using RODAC plates or swabs, preferably before and always after room sanitization and cleaning. Nonviable airborne particulates are measured using calibrated laser-type particle counters while rooms are operating under both static and dynamic conditions (i.e., with personnel present performing all expected operations and activities). Dynamic conditions present a genuine challenge to an HVAC system to maintain air quality, and the test results obtained provide insight into the contaminants products will likely be exposed to. Three days of monitoring under each set of conditions are usually adequate to detect excursions. Air and surface sampling are always conducted where critical operations are performed (e.g., at vial filling or where aseptic connections are made). Those areas where sterile materials are open to the environment, even momentarily, must be monitored during PQ. This includes stopper bowls on filling machines and where filled vials are loaded into lyophilizers.
HVAC PQ also includes testing to prove that rooms and areas are maintained within specified ranges of temperature and relative humidity. This testing may be performed using room instrumentation, provided that instruments are calibrated and the building management system is qualified. One useful test is to demonstrate equivalency between portable temperature/relative humidity instrumentation and the building management system itself. Handheld instruments are placed in the geometric center of the room to be measured. Instruments are activated and allowed to collect data for 24 hours or more. Collected data are then compared with data recorded by the building management system during the same time period. There should be a close correspondence between both the portable instrument and building management system data. If not, one should challenge the placement of the building management system instrumentation because a true indication of room temperature and relative humidity does not exist.
The LVP regulations of 1976 clearly recognized the importance of designing, operating, and validating HVAC systems as one of several means for protecting product quality. FDA understood that the production of contaminated LVPs could have been avoided if HVAC and other critical systems were properly designed and validated. These dated regulations established design criteria, materials of construction, and performance standards for many systems and equipment used by industry today. Although never formally implemented, a lasting effect remains, which currently influences the design and validation of modern facilities. The contribution of the 1976 LVP regulations to drug safety and quality is largely unknown, but should be appreciated by all—critical design standards and the origins of validation were their outcome, details that are seldom recognized or understood.
William Garvey is a validation consultant at Millipore Corp., 290 Concord Rd., Billerica, MA 01821, tel. 978.715.1429, fax 978.715.1461, email@example.com
Where were you 30 years ago?
"I started in pharmaceuticals on May 4, 1981 with the old New England Nuclear, a highly regarded manufacturer of radiopharmaceuticals—not quite 30 years in industry, but 26 years, and only 5 months of unemployment during this time. I still have many of my old Pharm Tech magazines. Validation is not easy, partly because it is misunderstood. I am trying to remedy this. Basically, I have a lot to say and Pharm Tech is the medium I choose to use."
1. D.C. Mackel et al., "Nationwide Epidemic of Septicemia Caused by Contaminated Intravenous Products: Mechanisms of Intrinsic Contamination," J. Clin. Microbiol. 2 (6), 486–497 (1975).
2. "Nosocomial Bacteremias Associated with Intravenous Fluid Therapy—USA" Morbidity and Mortality Weekly Report special supplement (Center for Disease Control, Atlanta, GA, Mar. 6 1971).
3. FDA, "Human Drugs—Current Good Manufacturing Practice in Manufacture, Processing, Packing or Holding of Large Volume Parenterals, and Request for Comments Regarding Small Volume Parenterals," Fed. Regis. 40 (106), 22202–22208 (June 1, 1976).
4. "Epidemiological Notes and Reports: Septicemias Associated with Contaminated Intravenous Solutions—Wisconsin, Ohio," Morbidity and Mortality Weekly Report (Center for Disease Control, Atlanta, GA, Mar. 17, 1973) pp. 99.
5. FDA, Guideline On General Principles Of Process Validation (Food and Drug Administration, Rockville, MD, May 1987).
6. X. Mao, "Energy Saving Tips for Desiging Air Handling Units (AHUs) in Cleanrooms," Pharm. Eng. 26 (2), 1–5 (2006).
7. W. Garvey, "Essentials of Validation Project Management, Part 1," Pharma. Technol. 29 (12), 68–76 (2005).
8. W. Garvey, "Essentials of Validation Project Management: Part 2," Pharma. Technol. 30 (1), 72–86 (2006).
9. EC, Guide to Good Manufacturing Practice Revision to Annex 1, Manufacture of Sterile Medicinal Products (European Commission, Brussels, Belgium, May 2003).
10. ISO 14644-1: Cleanrooms and Associated Controlled Environments-Part:1 Classification of Air Cleanliness (International Organization for Standardization, Geneva, Switzerland, 1999).