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Micro Molding and Micro Assembly of Medical and Drug Delivery Devices

12/1/17     Micro Engineering Solutions is a product development CMO specializing in the development of micro devices through Phase 1 Clinical trials.

This article is an excellent resource explaining the FDA ruling on rules and efficiencies of developing drug delivery devices in non-aseptic and non- cGMP facilities through Phase 1.  MES is well suited and equipped to execute testing and retain design history for this crucial and expedited phase of development activity.

Establishing cGMP Manufacturing Capability for Phase 1 Sterile, Dispersed, Injectable Dosage Forms



  1.  Introduction

As a product transitions from pre-clinical development to a clinical development phase, the manufacturing process takes on a much greater role in the overall success of the project. This transition is particularly difficult for emerging pharmaceutical companies whose expertise typically lies in the biology and chemistry of how their drug interacts with targets in the body, and less on the engineering, regulatory and quality aspects of manufacturing the drug product. This critical milestone is made even more challenging when the drug product is intended to be a sterile, injectable dosage form as the manufacturing and quality requirements can be overwhelming for a small company. Most small pharma companies turn to Contract Development and Manufacturing Organizations (CDMOs) to outsource this activity, as the cost to establish the capability internally often does not merit the investment for an early-stage product.

Many CDMOs do not provide manufacturing services for injectable products, and those that do often have facilities suitable for large scale production. Since early-stage products are almost always manufactured in small batches, there is a market need for CDMOs with the flexibility to provide manufacturing services for Phase I sterile dosage forms. For example, in some cases, it may be advantageous for a CDMO to establish a GMP area within a “laboratory setting” for the manufacture of drug product in early development. The rationale for this approach is to avoid the significant investment in setting up a dedicated facility and to create simpler, more flexible systems that meet GMP requirements, but are tailored for the specific activity envisioned. As long as the appropriate GMP controls are maintained, especially as related to operator safety, cleaning, and prevention of cross-contamination, there is  no compliance barrier to using “lab-type” facilities for the  manufacture of early phase clinical batches. This article describes the considerations for establishing this capability, and focuses on dosage forms that are sterile and dispersible.


  1. Regulatory Landscape for Phase 1 Dosage Forms

On September 15, 2008 the FDA made effective an amended rule that applies to small-molecule drugs and biologics, including vaccines and gene therapy products. The note in the Federal Register of 15 July 2008 (Volume 73, No. 136) announced an adaptation of 21 CFR 210 and 211: investigational medicinal products solely intended for use in Phase 1 are to be exempted from complying with the “final rule” under FD&C Act 505(i) (21 U.S.C 355(i)). The text stresses that the cGMP requirements of 21 CFR 211 are applicable only to Phase 2 and Phase 3 drugs (note, however, the exemption does not apply once the investigational drug has been made available for use by or for the sponsor in a Phase 2, a Phase 3 trial, or if the drug has been lawfully marketed).

“FDA’s position is that the United States’ [GMP] regulations were written primarily to address commercial manufacturing and do not consider the differences between early clinical supply manufacture and commercial manufacture,” the agency says.

For example, the requirements for a fully validated manufacturing process, rotation of stock for drug product containers, repackaging and relabeling of drugs and separate packaging and production areas need not apply  to investigational drug products made for use in Phase 1  trials, the agency says. This makes for solid rationale, as  the typical batch size needed for Phase 1 clinical trials is  typically much smaller in comparison to Phase 3 and  commercial scale batches, and hence the critical controls needed for Phase I should focus on safety of manufacture rather than qualification of processes at this point of drug development (note, however, the FDA did emphasize the importance of meeting the “statutory GMP requirements” of the Food and Drug Act ” 501 (a)2(B) which direct 21 CFR Parts 210 and 211).

In connection with the final rule on Phase I drug GMPs, the FDA issued a guidance recommending approaches to satisfy statutory GMP requirements for such drugs:

“During product development, the quality and safety of Phase I investigational drugs are maintained, in part, by  having appropriate [quality control (QC)] procedures in  effect,” the guidance states. “Using established or  standardized QC procedures and following appropriate cGMP will also facilitate the manufacture of equivalent or comparable IND product for future clinical trials as needed.”

While the basic requirements to reduce or eliminate  contamination that would cause adulteration in  non-sterile drug products are demanding, the standards for aseptic manufacturing of medicinal drug products are even more stringent. The pharmaceutical product must be non-pyrogenic, in addition to a strict sterility requirement.  Medicinal drug products that do not meet the sterility and non-pyrogenicity requirements can otherwise cause severe harm or a life-threatening health risk to the patient. Hence, these attributes are of utmost importance and concern during Phase 1 manufacture. Since the injectable dosage form must be sterile, the drug product can be terminally sterilized in its packaging, or manufactured aseptically.

Aseptic Manufacturing Regulations In Europe, aseptic manufacturing of sterile products is still seen as a last resort which is only acceptable if all methods of terminal sterilization in the final sealed container have  be excluded. Such being not feasible or applicable, for  example when the drug substance is thermally labile, the EU guidelines require the sterilization in the final container closure system whenever possible. Only the stability of the drug substance is considered, but not the container closure system. The European Pharmacopoeia (EP) prioritizes the terminal sterilization of the final container in manufacturing sterile drug products. The “EU Guidelines to GMP for  Medicinal Products for Human and Veterinary Use, Annex 1, Rev. 2008, Manufacture of Sterile Products” compiles the recommended procedures for sterile products and includes the aspects of aseptic manufacturing.

In the USA, the FDA’s 2004 publication “Guidance for  Industry Sterile Drug Products Produced by Aseptic  Processing” describes the expectations of the FDA for the validation of aseptic processing in a more detailed manner. This guidance updates the 1987 guidance primarily with  respect to personnel qualification, cleanroom design and  isolators, air supply system, integrity of container closure systems, process design, quality control, environmental  monitoring, and review of production records. The use of isolators for aseptic processing is also discussed. According to the  latest guidance, acceptance criteria for the  evaluation of media fill states that each contaminated unit should be examined independent of the number of filled units. The microbial environmental monitoring (more  frequency in testing) is accorded more importance to get greater quality assurance. Table 1 lists an overview of  regulatory guidelines for aseptic processing.


  1. Sterile, Dispersable Dosage Forms

Suspensions Some drugs are insoluble in all acceptable media and  must, therefore, for parenteral use, be administered as a suspension. One advantage is that drugs in suspension are often chemically more stable than in solution; however, their primary disadvantage is physical stability; i.e., that they tend to settle over time leading to a lack of uniformity of dose.  Issues with settling can be minimized by careful formulation and by shaking the suspension before each dose is  delivered. Physical stability in suspensions is controlled by  (1) the addition of flocculating agents to enhance particle  “dispersability” and (2) the addition of viscosity enhancers to reduce the sedimentation rate in the flocculated  suspension. Flocculating agents are electrolytes which carry an electrical charge opposite that of the net zeta potential of the suspended particles. The addition of the flocculating agent, at some critical concentration, negates the surface charge on the suspended particles and allows the formation of floccules, or clusters of particles, that are held loosely together by weak van der Waals forces. Since the particles are linked together only loosely, they will not cake and may be easily re-dispersed by shaking the suspension. Floccules have approximately the same size particles; therefore a  clear boundary is seen when the particles settle. Viscosity enhancers are typically hydrocolloids (natural, semisynthetic, or synthetic) or clays use in a concentration range from 0.5% to 5%, but the target viscosity will depend on the suspended particle’s tendency to settle.

A couple methods are used to prepare parenteral  suspensions. First, aseptically combining sterile powder  and vehicle involves aseptically dispersing the sterile, milled  active ingredient(s) into a sterile vehicle system (solvent plus necessary excipients); aseptically milling the resulting  suspension as required, and aseptically filling the milled  suspension into suitable containers. For example, this  process is used for preparation of parenteral procaine  penicillin G suspension. Or, second, in-situ crystal formation by combining sterile solutions. In this method active  ingredient(s) are solubilized in a suitable solvent system,  a sterile vehicle system or counter solvent is added that causes the active ingredient to crystallize, the organic  solvent is aseptically removed, the resulting suspension is aseptically milled as necessary, and then filled into suitable containers. For example, this process is used for testosterone and insulin parenteral suspensions.

Nano-Particles A drug’s low solubility often presents a serious challenge to developing bioavailable dosage forms. This challenge can be exacerbated for drugs with chemical stability issues when solubility-enhancing approaches utilize excipients that  are incompatible with the drug substance. To overcome these challenges many technologies have been developed including particle size reduction to nanometer-size drug crystals with greater surface area for dissolution, production of amorphous solid dispersions for reducing the energy  required for dissolution, and lipid-based drug delivery  systems for dissolving a hydrophilic drug in either a lipid  or oil phase.

Nano-Emulsions Oil-in-water emulsions, which are comprised of oil  droplets dispersed in an aqueous continuous phase, can provide unique solutions for overcoming drug solubility and stability problems; for example, Diprivan® (propofol), an  injectable anesthetic, is an nano-emulsion.

Emulsions can be characterized as macro, micro or nano. Macro-emulsions are typically opaque in appearance, since the average particle size of the hydrophobic droplet in a macro-emulsion is typically > 500 nm and thus scatters light.  Micro-emulsions and nano-emulsions are obtained when the size of the droplet is typically in the range of 50-500 nm. In addition, emulsions in this size range can appear translucent or optically clear if the average oil droplet size is < 100 nm, as droplets in that size range no longer scatter light.

The distinction between micro- and nano-emulsions  relates to their thermodynamic stability. Micro-emulsions  are thermodynamically stable due to the use of sufficient  co-solvents and co-surfactants to prevent Ostwald ripening – essentially the coalescence of the droplets into larger  particles. Ostwald ripening is the most frequent physical instability mechanism, although gravitational separation can also occur with larger particles. Nano-emulsions contain much less of the stabilizing co-solvents and co-surfactants, and as such are meta-stable and more susceptible to  Ostwald ripening. In addition, nano-emulsions require  greater kinetic formation energy, and are usually prepared using high-pressure homogenization or ultrasonic  generators. Because of the undesirable side-effects  caused by many solvents and surfactants, micro-emulsions are disadvantageous compared to nano-emulsions. In  order to achieve physically stable nano-emulsions, long chain triglyceride oils are sometimes employed, but  typically require the use of organic co-solvents or toxic co-surfactants (e.g., Cremaphor). The addition of co-solvents and co-surfactants significantly reduces the safety and  tolerability profile of the pharmaceutical formulation. These excipients may not be suitable for pediatric administration, may cause injection site pain and irritation, and are  becoming less acceptable in general for use in  pharmaceutical formulations.


  1. Facility Size & Manufacturing Space Considerations

Matching the product to an appropriate facility size is  important. Facility infrastructure typically increases along with facility size, and facility size increases with the scale  of the pharmaceutical project. The development phase of the drug will dictate the capacity requirements of the  formulation and fill. For larger, later stage production  activities the maximum capacity of the facility is critical to ensure success, but this is not a critical factor for early-stage development projects. It is important to evaluate the  product’s requirements and determine the best fit.

The ideal CDMO is one that can grow with a product’s  success, but this is difficult — if not impossible — to find.  Pure CMOs that manufacture high volume commercial  products typically lack the equipment and personnel to manage a developing product that requires low volume, and flexibility in scheduling. Companies that specialize in small volume early stage products have staff experienced in rapid small-scale manufacturing campaigns. A smaller support staff generally has greater flexibility with regard to changes and timing. The lead time for changes at a smaller CDMO should be less than for a CMO that is use to filling lots greater then 100,000 units per day. Although larger CMOs have much greater capacity, they tend to be more rigid and generally have defined systems in place that are not easily changed.  Scheduling is done well in advance (the lead time for scheduling or bringing a product in can be six months  to a year) so the lead time for changes can be a factor.  Evaluating the structure that you require for your stage  of production is an important aspect in choosing the  CDMO that will meet your current and potential  future requirements.


  1. Equipment – Both Process and Cleanroom

Cleanrooms are used in practically every industry where small particles can adversely affect the manufacturing  process. A cleanroom is any given contained space where provisions are made to reduce particulate contamination  and control other environmental parameters such as  temperature, humidity and pressure. The key component is the High Efficiency Particulate Air (HEPA) filter that is used to trap particles that are 0.3 micron and larger in size. All  of the air delivered to a cleanroom passes through HEPA filters, and in some cases where stringent cleanliness  performance is necessary, Ultra Low Particulate Air (ULPA) filters are used.

Cleanrooms are classified by how clean the air is. In Federal Standard 209 (A to D) of the USA, the number of particles equal to and greater than 0.5mm is measured in one cubic foot of air, and this count is used to classify the cleanroom. This metric nomenclature is also accepted in the most recent 209E version of the USA Standard. The newer standard  is TC 209 from the International Standards Organization  (ISO 14644-1). Large numbers like “class 100” or “class 1000” refer to the 209E Standard; the standard also allows  interpolation, so it is possible to describe e.g. “class 2000.”

Cleanrooms classified using single digit numbers refer to  ISO 14644-1 standards, which specify the decimal logarithm of the number of particles 0.1 µm or larger permitted per cubic meter of air. So, for example, an ISO class 5 cleanroom has at most 105 = 100,000 particles per m3. Both FS 209E and ISO 14644-1 assume log-log relationships between  particle size and particle concentration. For that reason, there is no such thing as zero particle concentration.  Ordinary room air is approximately class 1,000,000 or ISO 9.

Personnel selected to work in cleanrooms undergo extensive training in contamination control theory. They enter and  exit the cleanroom through airlocks, air showers and/or gowning rooms, and they must wear special clothing  designed to trap contaminants that are naturally generated by skin and the body. Since Phase 1 batches usually are  small scale, one popular alternative of CDMOs is to utilize compounding isolators for sterile manufacture.  Isolators consist of a decontaminated unit, supplied with class 100 or higher air quality that provides uncompromised, continuous isolation of its interior from the external environment (e.g., surrounding clean room and personnel).

An isolator is defined as an ISO 5 enclosure if it meets the following criteria: •  uses rapid transfer ports or another type of  decontaminated, high-integrity interface to transfer compounding materials into the isolator; •  uses an automatic sporicidal  decontamination system; •  constantly maintains a significant overpressure  relative to the surrounding environment; and •  the manufacturer provides documentation verifying that the isolator can maintain ISO 5 at all times.

Any Compounding Aseptic Isolator (CAI) that does not meet all of the isolator criteria would be classified as a restricted access barrier system (RABS). A RABS is an ISO 5 enclosure that provides a physical separation from the compounding area through the use of glove ports, but the openings for transferring materials would not provide the same level of protection as an isolator. In addition, the RABS is cleaned and decontaminated manually.

Aseptic Manufacturing Considerations Aseptic manufacturing consists of a lot of single working steps. But the whole process is only as good as the worst single step. To achieve the aim of a sterile product, several aspects have to be considered and have to be separately validated. In the end, process simulation with media fill is the key validation measure and allows the final evaluation of the appropriateness of the whole process. It is state-of-the-art  to produce medicinal products under aseptic controlled  conditions. This control requires monitoring of the  environment. The design of the monitoring (frequency,  number of sampling sites, method of sampling, procedure  in regard of deviations etc.) is not specifically mandated;  however, the common aim is to recognize any deviation  of the validated state.

The necessity of monitoring the environment as a  key element of a quality assurance program is widely  accepted. Air, surfaces and personnel are all identified as contamination risk sources for the environment. To come to reasonable limits, the rooms of the production areas have firstly to be classified depending on the production step. Limits of air, surfaces and personnel are proposed under consideration of the official recommendations. There are separate requirements for non-viable air particles, and for viable organisms, and the time when the measurements are performed (either at rest, or in operation). The differences determine the nomenclature for clean rooms. Both  personnel and material flow should be optimized to prevent  unnecessary activities that could increase the potential for introducing contaminants to exposed product, container  closures or the surrounding environment. Air (including  purified air) is a main source for contamination. Per EU GMP, viable airborne particles have to be identified and regarded in batch release.  Surfaces which have immediate contact with the product are highly critical. Indirect transfer of  particles from surfaces via air must also be taken into  account. The design of the facility (smooth surfaces without unevenness and tears) is important to avoid contamination and support the success of sanitization procedures.


  1. Quality Control, Approach & Audits

Although quality is the responsibility of all personnel  involved in manufacturing, it is highly recommended that individual(s) who are assigned to perform QC functions are independent of manufacturing responsibilities, especially for the cumulative review and release of phase 1 investigational drug batches.

The CDMO engaged in the manufacture of phase 1  investigational drugs should follow written manufacturing and process control procedures that provide for the  following records:

  • A record of manufacturing data that details the materials, equipment, procedures used, and any problems encountered during manufacturing.  Production records should be sufficient to replicate the manufacturing process. Similarly, if the  manufacture of a phase 1 investigational drug batch is initiated but not completed, the record must  include an explanation of why manufacturing  was terminated; •  A record of changes in procedures and processes used for subsequent batches along with the  rationale for any changes; and •  A record of the laboratory (quality control and  microbiological) that have been implemented  (including written procedures) for the production  of sterile-processed phase 1 investigational drugs.

In the early stages of drug development, processing  parameters will be adjusted to meet efficiency targets  better and/or overcome processing hurdles. The CDMO  making these adjustments should have a formal change  control system that allows the client to present this  documentation to the FDA (or other agency) during  later stage filings.

Proper QC documentation also includes a Quality  Agreement. The quality agreement should define  expectations between the CDMO and the sponsor  to review and approve documents, and how they will  communicate with each other, both verbally and in writing.  It also should describe how changes may be made to  standard operating procedures, manufacturing records, specifications, laboratory records, validation documentation, investigation records, annual reports, and other documents related to products or services provided by the contract  facility. The quality agreement should also define owners’ and contract facilities’ roles in making and maintaining  original documents or true copies in accordance with cGMP.

It should explain how those records will be made readily available for inspection. The quality agreement also should indicate that electronic records will be stored in accordance with cGMP and will be immediately retrievable during the  required record-keeping time frames established in  applicable regulations.

Laboratory Controls Laboratory tests used in manufacturing (e.g., testing of  materials, in-process material, packaging, drug product) should be scientifically sound (e.g., specific, sensitive, and accurate), suitable and reliable for the specified purpose.  Tests must be performed under controlled conditions  and follow written procedures describing the testing  methodology. Records of all test results, procedures,  and changes in procedures, must be maintained. The main  purpose of laboratory testing of a Phase 1 investigational drug is to evaluate quality attributes including those that define its identity, strength, potency, and purity, as  appropriate. Specified attributes should be monitored,  and acceptance criteria applied appropriately. For known safety-related concerns, specifications should be established and met. For some Phase 1 investigational drug attributes, all relevant acceptance criteria may not be known at this stage of development as this information will be reviewed in the IND submission.

To ensure reliability of test results, calibration and  maintenance of laboratory equipment at appropriate  intervals according to established written procedures is  required. Personnel verify that the equipment is in good working condition when samples are analyzed (e.g., system suitability). A representative sample from each batch of Phase 1 investigational drug should be retained. Retention  of both the API and Phase 1 investigational drug in  containers used in the clinical trials is essential. The sample should consist of a quantity adequate to perform additional testing or investigation if required at a later date (e.g., twice the quantity necessary to conduct release testing, excluding testing for pyrogenicity and sterility). Storage and  retention the samples for at least two years following clinical trial termination, or withdrawal of the IND application is recommended.

Finally, initiation of a stability study using representative samples of the phase 1 investigational drug to monitor the stability and quality of the phase 1 investigational drug during the clinical trial (i.e., date of manufacture through date of last administration) should be performed under ICH temperature, humidity and light storage conditions.

Audits A drug sponsor should always visit the CDMO’s site during the evaluation process. This visit gives the drug developer a good overview of how the CDMO works. Touring the facility shows if it is a clean and functioning facility. Evaluate  whether the staff grasps the scope of your project, and determine whether the scientists have familiarity with the product type. Drawing on a CDMO’s experience can save time and potentially deliver a better outcome. For instance, a sponsor may believe that filling their product in a multi-dose vial is the best administration method for a clinical setting.  However, this practice could lead to errors in dosing, loss of extremely scarce product, and potentially determining the path forward for container stability. In the early stages  of drug development, processing parameters will be  adjusted to meet efficiency targets better and/or overcome  processing hurdles. The CDMO making these adjustments should have a formal change control system that allows the client to present this documentation to the FDA (or other agency) during later stage filings. After a successful site  visit, the next step is to conduct an in-depth audit.

During the audit you will review documentation systems  and discuss the project in more depth. All information and discussions should be viewed from a quality standpoint. First, learn about the company’s history, size, services,  financial stability, future plans for growth and technological innovations. Then determine the training of personnel and the expertise level of the staff. Find out about the Quality Assurance and Quality Control systems, manuals, reviews and methodology; also determine certifications, document management, procedures and problem solution systems, and equipment maintenance and calibrations. Also, look  at measurements/metrics for monitoring and controls,  deviations (the number and significance of them), technical transfer controls, capabilities, test methods and validations, material controls and inspections, supplier and material qualifications, purchasing controls, and laboratory controls.  Determine the GMP compliance history, and SOP (Standard Operating Procedures) records. From this review a drug  developer will be able to determine if a CDMO has the  technological knowledge, compliance record, and experience to provide solutions to problems and be able to complete documentation in a timely fashion. 7.  Personnel & Training

Double gloves are often used in industrial practice, as a  result of the dressing technique (the second pair of gloves is worn after finalizing the dressing). Some aspects for aseptic technique and behavior in the clean room are mentioned  in the FDA Guidance 2004. Very important for aseptic  manufacturing process are the detailed SOPs of the CDMO such as aseptic operation, gowning room cleaning as well as personnel and room environmental monitoring procedures.

Depending on the room classification or function,  personnel gowning may be as limited as lab coats and  hairnets, or as extensive as fully enveloped in multiple  layered bunny suits with self-contained breathing  apparatus. Cleanroom clothing is used to prevent  substances from being released off the wearer’s body  and contaminating the environment. The cleanroom  clothing itself must not release particles or fibers to prevent contamination of the environment by personnel. Cleanroom garments include boots, shoes, aprons, beard covers,  bouffant caps, coveralls, face masks, frocks/lab coats, gowns, glove and finger cots, hairnets, hoods, sleeves  and shoe covers. The type of cleanroom garments used should reflect the cleanroom and product specifications.

Low-level cleanrooms may only require special shoes having  completely smooth soles that do not track in dust or dirt. However, shoe bottoms must not create slipping hazards since safety always takes precedence. A cleanroom suit is usually required for entering a cleanroom. Class 10,000 cleanrooms may use simple smocks, head covers, and  booties. For Class 10 cleanrooms, careful gown wearing  procedures with a zipped cover all, boots, gloves and  complete respirator enclosure are required. 8.  Process Simulation Validation

All manufacturing procedures in a pharmaceutical  manufacturing operation must be validated – according  to European Pharmacopoeia and FDA guidelines. This  is especially important for aseptic manufacturing of  parenteral dosage forms, where contamination poses a significant patient risk. Process validation includes checks on the process by means of process simulation tests using microbial growth media (i.e., media fill tests). Since, in   pharmaceutical production, validated methods have been  already used for sterilizing equipment, processing air and  water and filtration techniques, media fill validation is very much focused on the aseptic technique of the human  operator. Intensive training and education of personnel is required in order to ensure that media fill validation is  recognized as a means of checking sterility level of aseptic processing. According to all guidelines, process simulation with media fill is state-of-the-art for validation of an  aseptic manufacturing process. Media fill means that a  microbiological nutrient media will be filled into a container closure system (ampules, vials, etc.) instead of the  actual product. The filled container closure systems are incubated under defined parameters and finally checked for microbiological contamination. This is to demonstrate that rooms, equipment and personnel are able to manufacture a product with very low contamination rate.

The EU GMP Guide provides more details on this issue: “Validation of aseptic processing should include a process simulation test using a nutrient medium (media fill) …  The process simulation test should imitate as closely as  possible the routine manufacturing process and include  all the critical subsequent manufacturing steps”.

The validation covers filling of media, environmental  monitoring, and incubation and evaluation of the filled  vials. Additionally the growth promotion properties of the  nutrient must be demonstrated. Microbiological examination of positive vials, bio-burden examination of the materials used and identification of contaminants are as well issues that need to be considered. The simulation should consider such conditions which simulate the highest risk (worst case) of maximum expected and permitted loads. Examples for worst case conditions are defined in ISO 13408. For example, for vial dimension and filling speed, the worst condition is the largest vial with the longest filling time. All interventions and measures of the usual process should be simulated in media fill. For example manual control of the filling volume, change in personnel, and performance of environmental monitoring. Even technical interruptions should be  considered (lack of air system, stopping of the filling  process, etc).

Liquid nutrient growth medium, capable of  supporting a wide range of microorganisms, is prepared, sterilized, and filled in simulation of a normal manufacturing process that includes compounding, sterile filtration,  in-process controls, sterilization of manufacturing process, materials (garments, primary containers, filling equipment), cleaning and sterilization process (e.g., cleaning in place – CIP / sterilization in place – SIP) and filling. The sealed  containers of medium thus produced are then incubated  under prescribed conditions and subsequently examined  for evidence of microbial growth. If the media fill reflects  the standard procedure of product filling, the contamination rate or contamination probability may be used as indicator for the safety of the production process. Comprehensive control of production environment, personnel, and installations, influencing the overall hygienic state of  manufacturing processes will be performed. Since, in  pharmaceutical production, validated methods have been already used for sterilizing equipment, processing air and water and filtration techniques, media fill validation is very much focused on the aseptic technique of the human  operator. Intensive training and education of personnel is required in order to ensure that media fill validation is  recognized as a means of checking sterility level of  aseptic processing.

Preparation of Media Fill Liquid nutrient growth medium, capable of supporting a wide range of microorganisms, is prepared, sterilized, and then filled to simulate a normal manufacturing process that includes compounding, sterile filtration, in-process controls, sterilization of manufacturing process, materials (garments, primary containers, filling equipment), and filling. The sealed containers of medium thus produced are then incubated under prescribed conditions and subsequently examined for evidence of microbial growth. If the media fill reflects the standard procedure of product filling, the contamination rate or contamination probability may be used as indicator for   the safety of the production process.

Environmental monitoring, comprising airborne counts,  particle counts, and hygiene status of personnel and  materials – e.g., balances and compounding vessels –  is conducted during the weighing and compounding of  materials. Prior to filtration, the pH-value of the nutrient broth is checked and in-process controls (IPC) on  identity, clarity, and bioburden are conducted. Samples   are controlled for analytical and microbiological controls  like that of any other product. Holding and process times  are documented and may be prolonged for validation  purposes. The bulk solution is sterile-filtered using the same filter material as in normal aseptic processing. Filter integrity is checked prior to and after use. Environmental monitoring is conducted at this processing step. Prior to filling, primary containers are sterilized and depyrogenized, the filling line is cleaned and sterilized (CIP/SIP) or transfer lines and dosage pumps are sterilized separately.

Number of Fill Units and Filling  Process Duration According to FDA Guidance the minimum number of filled units of media fill is 3,000 units (to reach a confidence level of 95% for demonstration of a contamination rate of less than 0.1%). For batch sizes smaller than 3,000 units,  smaller numbers are acceptable (requirements are given in ISO 13408 and EU GMP Guide Annex 1). For small batch sizes (for example products used for clinical trials) at least the actual batch size should be simulated during media fill.  For very large batches, it is recommended to simulate media fill with 1% of the actual daily batch size. The vials with the smallest and the biggest size should be regarded in media fill. Table 1 gives the minimum units require required for a media fill both for initial qualification and re-qualification  as well as the acceptable warning/action limits.



Table 1. First Qualification and Re-Qualification: Warning and Action Limits in Media Fill According to ISO 13408-1


Analytical Method Validation The extent of analytical procedures and methods validation necessary will vary with the phase of the IND. Hence the CDMO may elect to take a fundamental approach to  validation or qualification when appropriate. The main  goal of performing “staged’ validation in the early drug development is to provide test procedures that are reliable, able to support clinical studies, and evaluate the safety  of the product. The methods should use appropriate  parameters and sound scientific judgment, sufficient  information is defined as to ensure proper identification, quality, purity, strength, and/or potency. The validation data should be retained to link analytical procedures used in early phase/pivotal clinical  studies and a formal validation report with change  control may not be required. A brief summary of the validation studies is recommended to be submitted  in the original IND.

The suitability of an analytical procedure (e.g., USP/NF, the Official Methods of Analysis of AOAC International, or other recognized standard references) should be verified under  actual conditions of use. Information to demonstrate that USP/NF analytical procedures are suitable for the drug  product or drug substance should be included in the  submission and generated under a verification protocol.  The verification protocol should include, but is not limited  to: (1) compendial methodology to be verified with  predetermined acceptance criteria, and (2) details of the methodology (e.g., suitability of reagent(s), equipment,  component(s), chromatographic conditions, column,  detector type(s), sensitivity of detector signal response, system suitability, sample preparation and stability). The procedure and extent of verification should dictate which validation characteristic tests should be included in the protocol (e.g., specificity, LOD, LOQ, precision, accuracy).  Considerations that may influence what characteristic tests should be in the protocol may depend on situations such as whether specification limits are set tighter than compendial acceptance criteria.

Once an analytical procedure (including compendial  methods) is successfully validated (or verified) and  implemented, the procedure should be followed during  the life cycle of the product to continually assure that it  remains fit for its intended purpose. Trend analysis on  method performance should be performed at regular  intervals to evaluate the need to optimize the analytical  procedure or to revalidate all or a part of the analytical  procedure. If an analytical procedure can only meet the  established system suitability requirements with repeated adjustments to the operating conditions stated in the  analytical procedure, the analytical procedure should be  reevaluated, revalidated, or amended, as appropriate.  Over the life cycle of a product, new information and  risk assessments (e.g., a better understanding of product CQAs or awareness of a new impurity) may warrant the  development and validation of a new or alternative  analytical method. New technologies may allow for  greater understanding and/or confidence when ensuring product quality. Applicants should periodically evaluate  the appropriateness of a product’s analytical methods  and consider new or alternative methods. 9.  Conclusion

A small CDMO may choose to establish a GMP area  within a “laboratory setting” for the manufacture of drug product in early development. Also, the use of isolators and  modular cleanrooms provides flexibility for adjusting the manufacturing process to the product. Also, injectable,  sterile, dispersable products can be manufactured aseptically to avoid a terminal sterilization requirement. The FDA has provided an amended rule that stresses that the cGMP  requirements of 21 CFR 211 are applicable only to Phase 2 and Phase 3 drugs and has provided guidance on the  requirements for small-scale Phase I cGMP manufacture.

Some of the regulatory burden is lifted for the manufacture of Phase I materials as long as basic tenets of quality control and validation are met.