Sterile Product Manufacturing

Introduction To give an overview of the principles involved in the manufacture of sterile products The overall objective is to produce product that has a high assurance of sterility (and which meets all other quality parameters) This presentation: Summarises the general approach Gives a framework for other detailed guides on specific aspects of sterilisation & sterile manufacturing Illustrates the underlying principles Provides advice and gives recommendations.

General Principles of Sterile Manufacturing Moist Heat Sterilization Dry Heat Sterilization Aseptic Processing Environmental Monitoring Ethylene Oxide Sterilization Sterile Filtration Water systems validation Sterility testing Radiation Sterilization Visual Inspection

Fundamentals Sterility is the absence of living organisms This is an absolute definition The probability of achieving sterility depends on the overall process It is generally accepted that a terminally sterilized product should have a probability of non-sterility of less than 10-6 (i.e., a lower probability than one in a million of having a non-sterile unit) This is often expressed as an SAL Sterility Assurance Level of 106 This is a worst-case figure (with a challenge more resistant than product bioburden). Real confidence levels are generally very much higher A figure that has sometimes been quoted for aseptically filled product is probability of non-sterility of less than 10-3. However, this is harder to analyse as contamination does not follow a clear statistical distribution. Potential contamination sources are not randomly distributed.

Why Validate and Control? The test for sterility cannot confirm that the whole batch is sterile It is performed on a sample from a batch and has statistical limitations It can miss contamination if only a proportion of units are non-sterile It is thus necessary to recognize and understand every aspect that could lead to loss of sterility assurance Such conditions should be prevented by the application of carefully designed barriers and/or control measures.

Development – Validation and Control It is important that the product and process are designed to maximise sterility assurance Wherever possible, the product should be developed to withstand sterilization in the final container Once the product design is defined, a suitable production process must be developed This is installed and validated The process must then be tightly controlled to assure reliability and consistency.

Product Design Considerations For New Products: Define product and processing requirements Consider stability of product to the sterilization conditions Base the process on achieving the required sterility assurance level Where possible choose terminal sterilization in final container Define process flow and the important microbiological aspects Ensure changes are subject to strict change control For reviewing existing (marketed) products: Establish the process description and assess in detail Preferably, sterilization should be by compendial procedures Where other procedures are registered, assess SAL Where necessary (if existing SAL is too low) may need to improve process and maybe re-register Require justification & validation.

Facility Design Must be in compliance with company policies and procedures, for example: Must minimise the risk of contamination at all critical stages Required Grades of Clean Rooms : need to be appropriate for the process - e.g. for Terminal Sterilization or Aseptic Fill Personnel Access and Material Flow Restricted access, correct gowning Materials flow, air locks, decontamination, segregation HVAC-System Segregation/Dedicated HVAC of correct standard Requires control of Filtration/ΔP/Air Flow/Temp./Pressure/Humidity Air flow patterns demonstrated No sinks and drains in Zone A/B areas, air breaks to drains in others Surfaces and ease of cleaning: smooth unbroken impervious surfaces

Cleaning and disinfection of the Facility Cleaning and disinfection is important in environmental control Efficacy needs to be validated Validated procedures, conducted consistently In class A & B areas, the cleaning and disinfectant materials must be sterilized And need to minimise contamination risk in other areas Operating procedures must include, at minimum: Preparation of cleaning materials (and sterilization if applicable) Exact procedure of cleaning & disinfection. Responsibility & scheduling. Type and concentration of detergents and disinfectants. Type of cleaning tools. Training is required for cleaning and disinfection of clean rooms Routine decontamination using formaldehyde gas should be avoided.

Water All water systems require good design and validation Typically, for pharmacopoeial grades, validation includes Two studies over a total of 4 weeks to assess against the acceptance criteria, Additional 11 months to verify that the system remains under control Must demonstrate consistent production of water of the required quality Physico-chemical, Microbiological, Biological (endotoxin, where applicable) Water systems must be regularly monitored following a defined written monitoring plan based on results of the validation studies.

Categories of Water Water for Injections (WFI) For injectables formulation Final rinse water for product-contact items (for injectables) Freshly prepared or from a validated hot (e.g., >75°C) storage /distribution system or otherwise protected from microbial contamination Highly Purified Water (HPW) To European Pharmacopoeia Purified Water (PW) For initial washing of product-contact items Prepared, suitably stored and distributed to maintain quality and prevent microbiological proliferation, following the relevant company procedures.

Gases and Vacuum Gases Vacuum Systems Specification equivalent to the room air quality where it is to be used In aseptic applications, gases are to be filter sterilized Consider sterile filtering non-product contact gases for aseptic applications. (But, note safety considerations, e.g. avoidance of leakage) All gas filters to be integrity tested on installation and at defined intervals Vacuum Systems Sometimes used for cleaning and dust control May be mobile units, fitted with exhaust HEPA filters Or may have central dust collection On these, use dedicated vacuum pumps’ protected against back-flow Design to prevent unprotected route into the aseptic suite.

Equipment (1) Equipment Qualification To include the critical aspects for sterile product processing Qualification of critical aspects of moist heat sterilization, aseptic processing, dry heat sterilization etc. Cleaning and Sanitization of Equipment Equipment designed for easy cleaning and sanitization For Terminal Sterilization applications, low microbial challenge. Where possible, critical surfaces should be sterilized For aseptic work, the critical (product contact) surfaces must be sterilized before use. In exceptional cases where this is not possible (e.g., some stopper bowls), they should be sanitized by a validated method Cleaning validation must show effectiveness and absence of residues.

Equipment (2) Equipment Sterilization and handling Sterilization must follow a validated procedure Aseptic processes designed to minimise aseptic assembly and intervention Unavoidable aseptic assembly needs clear & precise procedures Aseptic assembly must be simulated (worst-case) in media fill simulation trials Sterilization In Place is a good method where possible – must be validated.

Personnel Training - personnel appropriately trained for sterile processing, including assessment and documentation: Basic GMP Fundamentals of microbiology Personal hygiene, health and cleanliness Behaviour and aseptic working techniques Gowning and entry procedures Cleaning and disinfection Sterilization procedures, validation and routine operation Emergency procedures to protect product quality (e.g. loss of HVAC System, loss of power, equipment interventions etc.) Personnel participating in aseptic processing must have practical training in aseptic techniques before doing aseptic manipulations They must have participated in a successful media fill run.

Gowning and Aseptic Technique Personnel must correctly wear appropriate clean room garments Detailed, easily understood, gowning procedure (preferably illustrated) Aseptic Techniques Personnel in the aseptic manufacturing area, must understand the principles of aseptic procedures They must only be considered qualified after appropriate training, working under supervision and demonstration of competence The supervisor should observe technique & correct as necessary All personnel directly involved in aseptic processing must participate in a media fill at least once per year Glove disinfection Sterile disinfectants must be available (e.g., alcohol based) Glove disinfection must be reasonably frequent, defined in SOP.

Environmental Monitoring (1) The scope of environmental monitoring includes: Non-viable particulates, Viable (microbial) counts Differential pressures Temperatures Humidities Air flows

Environmental Monitoring (2) Monitoring During Room Qualification Operational Qualification (OQ) at rest conditions to verify operation Performance Qualification (PQ) in worst case operational conditions Action levels should meet USP or Euro GMP as applicable Alert levels tight enough to detect deterioration, but not so tight that they become meaningless due to frequent transgression PQ must cover a sufficient period to establish consistency Routine Monitoring Ensures area remains satisfactory. Results should be within alert level Results above alert levels need review and perhaps corrective actions Above action levels, must trigger appropriate actions (described in guide), Results must be assessed for trends so that progressive or sudden changes in the results may be observed. This should be reviewed regularly.

Environmental Monitoring (3) Deviation Reports and Failure Investigations The data must be analysed Where necessary further investigations initiated Possible contamination sources to be assessed and, eliminated Outcome and detail must be reported Recommended Methods for Routine Monitoring Physical measurements of the air supply Physical and microbiological monitoring of the environment Particles (viable and non-viable) in the air Micro-organisms settling out of the air Micro-organisms contaminating surfaces Presence of micro-organisms on the hands and garments Monitoring Plan Defined monitoring plans: tests, locations, alert/action levels & frequencies May contain details of water, compressed gas clean steam testing A review of environmental data is a requirement for batch release.

Bioburden and Components Active Ingredients, Excipients, Additives All ingredients should have appropriate biological specifications Any limitations to sterilization must be defined Description of origin (e.g. virological / prion risk) Materials Used in the Process Where appropriate, determine bioburden (e.g., ion exchange materials) Primary Packaging Components Container and the closure and cleaning / sterilization to be clearly specified Steps such as siliconization may need monitoring If cleaning/sterilization is by supplier, same exigencies apply Container-closure integrity The integrity must be validated Simulate, where appropriate: stress from processing Method appropriate to container/closure system

Weighing, Compounding and Sterilization Weighing and compounding must be carried out in suitably classified rooms Vessels must be cleaned, and sterilized or sanitised as appropriate and stored dry in a way to prevent microbial contamination Storage of pre-sterilization intermediates to be controlled & time limited Following aspects to be considered: Pre-filtration bioburden (filter sterilized material) Pre-sterilization bioburden Appropriate in-process controls Sterilization of product and product contact materials Selection of a suitable sterilization protocol must be based on SAL Method must also consider the stability of the product Validation always required Change control is vital; even apparently minor change must be assessed

Terminal Sterilization Steam Sterilization By far the most common method for aqueous-based pharmaceuticals Preferred cycle is the Pharm Eur reference cycle is 15 minutes at 121°C The sterilization cycle chosen must be compatible with product stability Sterilization parameters clearly defined In conjunction with other controls, the required SAL must be demonstrated Validation to confirm sterilization conditions consistently throughout the load Sterilization by Ionizing Radiation Common for medical devices, but not for pharmaceuticals. Pharm. Eur. reference condition, 25 KiloGray (kGy), has been widely accepted. Other conditions may be used if validated and accepted by the regulator Important to consider susceptibility of the product to radiation damage Dry Heat Sterilization Lower antimicrobial efficacy than moist heat, thus higher temperatures and/or longer exposures. Pharm Eur reference cycle is 2 hours @ 160°C Rarely used for terminal sterilization of pharmaceuticals; in rare cases heat resistant non-aqueous products may be terminally sterilized.

Sterilization of Items for Aseptic Fill (1) Steam Sterilization Widely used, but careful validation needed – particularly complex items Broadly similar to terminal steam sterilization, but two aspects are critical Quality of saturated steam Removal of air and subsequent steam penetration Sterilization by Ionizing Radiation May be used for temperature sensitive primary packaging or components Used for disposables for sterile areas and sterility testing areas Validation includes dosimetry, - correct, even, irradiation of the items Dry Heat Sterilization/Depyrogenation Sterilization/ depyrogenation of heat resistant primary packaging materials Pharm Eur notes that temperatures in excess of 220 oC have been frequently used, the USP suggests 250 ± 15 oC Validation must include endotoxin challenge studies Dry heat may be used to sterilize non-aqueous preparations (e.g. Ointment bases) at lower temperature/time relationships, without depyrogenation.

Sterilization of Items for Aseptic Fill (2) Ethylene Oxide Sterilization Quite widely used to sterilize heat labile components European Pharmacopoeia and the European GMP guide indicate that this method should only be used where there is no suitable alternative Hazardous - toxic, potentially carcinogenic, flammable, potentially explosive Generally conducted by specialized contractors There are strict regulatory limits on maximum permissible product residues Bulk packs for sterilization must be gas permeable, but sealed against microbial ingress Sterilization must consider packaging, load pattern, gas penetration (ethylene oxide & water vapour), bulk pack integrity Validation and routine monitoring must include Biological indicators.

Sterilization by Filtration (Liquids) Principle: Contaminating organisms are not killed, but are retained on the filters. Any faults in the filter structure, may compromise this Validation includes: Retention of bacterial challenge: B. diminuta at 107 per cm2 This is correlated with an integrity test value Validation should address: Filter suitability - toxicity, extractables, shedding of particles Adsorption of product Compatibility with product solvents The required filter size and suitability of the filtration equipment Retention of B.diminuta in the actual product under process conditions Parameters for the physical integrity test Routine Filtration Conducted in line with the validated parameters Check integrity testing, process time, differential pressure, flow rates, sterilization and reuse of filters.

Performance Qualification of Aseptic Manufacturing Based on simulating the risk of contamination in all aseptic operations For a new process, a minimum of three consecutive satisfactory media filling trials For aqueous liquid products, simulation trials use a liquid microbiological medium For solid dosage forms, a powder ‘placebo’ is used, followed by aseptic reconstitution into a liquid microbiological medium The following slide gives a general overview....

Aseptic Process Simulation (Media Fill Trial) Media Fill Trials (MFTs) All process stages simulated as closely as possible Particularly interventions and manual manipulations Must follow routine procedures and include all interventions Regular interventions simulated with the same frequency as actual process In each case, the worst-case eventuality must be covered Process must be successfully validated before product filling is permitted Revalidation by media fill must be conducted every half year (each line) Manufacturing Environment Microbiological monitoring must be performed during the trial Filling Conditions and Equipment All according to routine operating conditions and at normal times of day Containers must be passed through all stages.

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