After the potential hazardous contaminants from the manufacturing process have been identified during the review of the process flow, the acceptable levels for the contaminants is determined. For contaminants with complete toxicological data available, follow ISO 10993-17 to set the cleaning limits for the contaminants. When limited toxicological data is available, at a minimum the LD50 values can be used to calculate the cleaning limits. For most contaminants the LD50 values are readily obtained from the MSDS.
The established cleaning levels are then used in the selection and evaluation of the cleaning test methods.
ABSTRACT
Recent changes in the FDA’s 510(k) requirements for medical device applications have spawned many inquiries from clients on how to address the request for extractables, leachables and drug compatibility data. Meeting the expectations of the CDRH can be challenging in that any given study design is not universally applicable to all devices. A good study design requires elements of the best practices documented in ISO-
10993-12, the PQRI guidance for E&L testing of OINDP as well as any specific requests for drug compatibility data from CDRH.
A hybridized study design, incorporating the essential regulatory elements, has been developed and successfully implemented for a variety of medical device applications. The rationale behind selection of the elements, overall experimental design strategy and interpretation of the resulting data will be presented.
INTRODUCTION
Extractables and leachable testing is required by the CDRH in the FDA for many medical devices. Experimental design for evaluation of extractable and leachables from medical devices can be done based on the most likely route for a leachable to enter the body. One route of entry is for leachables from a medical device to enter a drug product that carries the leachable into a patient. Examples of medical devices were
this is the leachable route of entry include infusion pumps, syringes, and syringe filters. For leachables in this category, both the toxicity of the leachable and the potential impact of the leachable on the drug product
need to be considered. The second route of entry is direct migration of the leachable from the medical device into the patient from direct tissue contact. Examples of medical devices where this is the leachable route of entry include dental implants, artificial joints, stents, bandages, and contact lens. For some medical devices, both routes of entry for leachables are possible. Examples of medical devices where both routes of
entry are possible include drug releasing implants and catheters. If both routes of entry are possible, follow
the second experimental design for direct migration route of entry. If leachables from a medical device are unlikely to enter the body from one of these two routes, an evaluation of extractables and leachables is probably not necessary.
Until recently, only medical devices where the leachable route of entry was from direct tissue contact were required to perform extractable and leachable testing. This requirement has changed as evidenced in the below example of a recent response from the FDA to a 510 (k) for an infusion pump:
“For each route of administration identified in your statement of intended use, you should identify an FDA approved drug or biologic to demonstrate that at least one such product is approved for infusion through the proposed route of administration and at the proposed dosage.
If your infusion pump includes a reservoir, we recommend that you provide stability and compatibility data for each drug or biologic that you have identified above, which assesses the stability and compatibility for the recommended use period and conditions included in your labeling.
In addition to demonstrating that the drug or biologic retains its specifications, we recommend that you include a safety evaluation of any leachables, extractables, impurities and degradants. Analytical methods should be used to identify and quantify impurities, degradants, leachables and foreign particulates in the effluent.”
There are two important requests in this FDA response to the 510 (k). The first request is to assess the stability and compatibility of each drug or biologic intended to be used with the medical device. The second is a safety evaluation of any leachables, extractables, impurities and degradants from the medical device into the drug product.
To address extractables testing for medical devices, in the FDA Modernization Act of 1997, the FDA recognized ISO 10993-12 Titled “Sample Preparation and Reference Materials”. In this document are clearly defined extraction experiments for extractable and leachable evaluations. Some of the definitions and experiments in ISO 10993-12 are similar to the definition of an extractable and the forced extraction studies described in the PQRI guidance for E&L testing of OINDP. Acceptance criteria for extractables and leachables are not defined in ISO 10993-12.
Based upon the similarities between ISO 10993-12 and the PQRI guidance for E&L testing of OINDP, a study design for medical devices where the route of entry for leachables is in a drug product will be presented that includes elements of both documents. The study design to be presented for medical devices where the leachable route of entry was from direct tissue contact will be based only on ISO 10993-12.
STUDY DESIGN
Extractables and leachables study design for medical devices where the route of entry for leachables is in a drug product
Before starting to evaluate drug compatibility and leachables from the medical device, an FDA approved drug(s) intended for use with the medical device must be selected. If the device is intended for just one drug, like an insulin pump, the selection of the drug is obvious. If the device can be used with multiple drugs and multiple routes of administration, select a total of three drugs that are commonly used from the three most common routes of administration. For example, if evaluating an infusion pump that is intended to deliver drugs intravenously and as an epidural, pick two common drugs for intravenous infusion and one for epidural infusion. Once the drug(s) has been selected, pick the simplest formulation of the drug to evaluate drug compatibility and leachables.
To address drug compatibility and leachables from the medical device, the experimental approach is divided into two steps. The first step is the determination of extractables from the medical device in controlled extraction studies. Based upon these results, analytical methods are then developed to be used to evaluate leachables in the second step. The second step is the evaluation of leachables from the medical device into the drug product, and the evaluation of drug stability in the medical device.
Only the components of the medical device that directly contact the drug product need to be included in the controlled extraction study although other components can be included if deemed to present a significant risk. Separating components of the medical device for extractions will facilitate the identification of extractables, but the medical device can be extracted intact if separation is not practical.
An overview of the controlled extraction study can be found in Table 1 and is similar to what is done for a sample container closure system following the PQRI guidance for E&L testing of OINDP. The medical device is extracted in a polar solvent and a non-polar solvent with the solvents selected based on the representative drug products. The extraction type is based on the solvent type and the analytical methods for analysis of extractables are the same for all extractions. Extractables are identified by MS and quantitated against structurally similar standards.
Table 1. Overview of Controlled Extraction Study
Solvent Extraction Type Analytical Methods 1. Polar – buffer(s) that match (or bracket) the pH and ionic strength of the drug product vehicle(s), water
2. Non-polar – 50/50
Ethanol/water if drug product contains surfactants, IPA if drug product contains no surfactants
1. Neat solvents : Soxhlett
2. Mixed solvents and buffers: Batch extraction with agitation or reflux
1. Volatile organic extractables by GC-MS
2. Non-volatile organic extractables by LC-MS
3. Inorganic extractables by
ICP-MS (aqueous extract only)
Once the extractable profile of the medical device has been determined, analytical methods are then developed that can analyze for the extractables present as leachables in the representative drug products. Hopefully GC-FID and HPLC-UV methods can be developed for the organic leachables, but detection by MS may still be needed based upon the extractables identified and the number of unknowns. For both methodologies the drug may present significant interference for detection of potential leachables and extensive sample preparations, like liquid-liquid extractions, may be required. For inorganic leachables, ICP- MS is commonly used. All of these methods should be validated for accuracy, precision, specificity, LOD/LOQ and linearity. Acceptance criteria for validation should be set based upon the demonstrated performance of the method and the intended use of the method.
Analytical assay methods are also needed to demonstrate the stability and compatibility of each drug with the medical device. If available, the USP method for the drug product should be used. If a USP method is not available for the drug product, an analytical assay method will need to be developed and validated.
Once all methods are in place, the experimental steps shown in Table 2 are followed.
Table 2. Steps in Study To Determine Drug Compatibility and Leachables from Medical Device
Acceptance criteria are not universally defined. For assay we recommend setting the difference between the control and the sample to be the same as the USP acceptance criteria for assay. For example, if the USP method has the assay value for a drug product to be +/- 10.0 % of label claim, the acceptance criteria for compatibility should be that the assay value for the sample be within +/- 10.0% of the assay value of the control. For leachables and medical device impurities we recommend using the same acceptance criteria as process impurities of 0.05% of the drug product label claim.
Extractables and leachables study design for medical devices where the leachable route of entry is from direct tissue contact
To address extractables and leachables, two different extraction studies are done. The first experiment is an exaggerated extraction study which is defined in ISO 10993-12 as “any extraction that is intended to result in
a greater amount of a chemical constituent being released as compared to the amount generated under the simulated conditions of use”. An exaggerated extraction study is a forced extraction study to generate a complete extractable profile for hazard identification and is required by ISO 10993-12 to be exhaustive. The second experiment is a simulated use experiment which is defined in ISO 10993-12 as “evaluating leachable material levels available to the patient or user from devices during the routine use of a device using an extraction method that simulates product use.” The experimental conditions in a simulated use experiment are modeled after the intended tissue environment for the device with the goal of determining leachable exposure to the patient.
An overview of the exaggerated extraction study can be found in Table 3. The key decision in study design is solvent selection. For an exaggerated extraction study, the extraction solvents are selected based upon the anticipated tissues the device will encounter. The extraction type is based on the solvent type and the analytical methods for analysis of extractables are the same for all extractions. For exaggerated extractions, the extraction must be proven to be exhaustive, therefore extraction time is established experimentally. Extractables are identified by MS and quantitated against structurally similar standards.
Table 3. Overview of Exaggerated Extraction Study
Solvent Extraction Type Analytical Methods1. Polar – water, phosphate buffered saline, culture media without serum
2. Non-polar – vegetable oil, ethanol/water, ethanol/saline, polyethylene glycol 400, dimethyl-sulfoxide, culture media with serum.
1. Low boiling neat solvents : Soxhlett
2. Mixed solvents, buffers and high boiling neat solvents: Batch extraction with agitation or circulation
1. Volatile organic extractables by GC-MS
2. Non-volatile organic extractables by LC-MS
3. Inorganic extractables by
ICP-MS (aqueous extract only)
An overview of the simulated use extraction study can be found in Table 4. Again the key decision in study design is solvent selection. Like the exaggerated extraction study, the extraction solvents are selected based upon the anticipated tissues the device will encounter and the results of the exaggerated extraction study. The extraction type is batch extraction with agitation and the analytical methods for analysis of leachables are the same for all solvents. The extraction conditions should be the highest temperature listed that does not exceed the glass transition temperature of the material. Leachables are identified by MS and quantitated against structurally similar standards.
Table 4. Overview of Simulated Use Extraction Study
Solvent Extraction
Type
Extraction
Conditions (select one)
Analytical Methods 1. Polar – water, physiological saline, culture media without serum
2. Non-polar – vegetable oil, ethanol/water, ethanol/saline, polyethylene glycol 400, dimethyl- sulfoxide, culture media with serum.
Batch extraction with agitationa) 37°C for 72 hours b) 50°C for 72 hours c) 70°C for 24 hours d) 121°C for 1 hour1. Volatile organic extractables by GC- MS
2. Non-volatile organic extractables by LC-MS
3. Inorganic extractables by ICP- MS (aqueous extract only)
Acceptance criteria for the levels of extractables and leachables in a medical device are not included in ISO
10993-12. A risk based approach method to set acceptance criteria that includes a toxicological evaluation of each extractable and leachable is presented in ISO 10993-17 but this approach may not be recognized by the FDA. A second option would be to use a predefined default level appropriate for the device and its intended use.
If the medical device contains a drug (e.g. a drug releasing implant), sample selection needs to be
considered and can be different for the above two extraction studies. Depending upon the amount of drug in or on the device, a “placebo” device without drug may be considered for the exaggerated extraction study to avoid excessive interferences from the drug in the identification of extractables. However, the final medical device including the drug should be used in the simulated use experiment since the presence of the drug could effect the migration of the leachables from the device.
CONCLUSION
Extractables and leachables testing are required by the CDRH in the FDA for many medical devices. A
study design was presented that was based on both ISO 10993-12 and the PQRI guidance for E&L testing of
OINDP for medical devices in where the route of entry for leachables is in a drug product, and a second study design was presented based only on ISO 10993-12 for use on medical devices where the leachable route of entry is from direct tissue contact. Both study designs have been used to support successful 510(k) submissions.
REFERENCES
There should already be in place a strong quality program at the CRO and the quality agreement must make a good fit to this program. Those concerns (terms) that are rather common to Quality Agreements should already be addressed in the existing quality program at the CRO or else consideration must be given to incorporating them into the existing program. This approach is distinctly different and better than leaving them only in the quality agreement. To leave important concerns only in the quality agreement is tantamount to instructing the lab to only consider doing such quality work when working on this particular client’s project.
At the end of the stability study, results from the leachables analyses will be reported. There are two basic outcomes to a leachables study:
Pine Lake Laboratories is fortunate to have Dr. Michael Ruberto as a retained consult available to support all extractable and leachable studies.
Dr. Ruberto is the President of Material Needs Consulting, LLC which provides consulting services to manage the development and commercialization of medical devices and packaging, with a special emphasis on material selection, extractables and leachables, and supply chain management. He has been an active member of various pharmaceutical working groups that have developed “best practices” for characterizing and evaluating the safety of container closure systems and packaging for several different drug dosage forms. Some of these teams include:
Dr. Ruberto was formerly the Head of Regulatory Services for the NAFTA region at Ciba Specialty Chemicals where he was responsible for worldwide notifications of new products, food contact notifications, and regulatory compliance of Ciba chemicals. At Ciba Dr. Ruberto also served as the Director of Analytical Research. Dr. Ruberto was employed by Ciba for fifteen years.
Dr. Ruberto received a B.S. with thesis from Stevens Institute of Technology and a Ph.D. in Analytical Chemistry from Seton Hall University.
To learn more about Dr. Ruberto, please visit www.materialneedsconsulting.com
For bioanalytical methods for small molecule drugs in biological matrices, sample preparation is a critical step. A balance must be achieved between a sample preparation method that reduces interferences while still being affordable and fast. At Pine Lake Laboratories, we have successfully developed and validated a wide variety of bioanalytical methods that achieved this balance. We have experience with mixed mode extraction, liquid-liquid extraction, solid phase extraction, protein precipitation and enzymatic digestion sample preparation methods. We have the experience and expertise to develop the bioanalytical method needed to help advance your drug to the patients who need it.
A major challenge at the contract lab (CRO) is to handle Quality Agreements (QAGs) through some standardized procedure, while at the same time allowing for the diverse needs of a wide client base. This becomes more evident when one considers that the QAG typically originates with the client, in their format, and therefore contains many client-specific idiosyncrasies. Furthermore, the contract lab may be performing laboratory testing under GLP, GMP and/or ISO laboratory testing protocols, which, although greatly similar to one another, will each have its own unique requirements. Procedures, to be useful, must be detailed enough for personnel to be trained on and to follow. However, to be standardized across the wide client base, they must not be too detailed. One cannot have a procedure for each client. Management must therefore “see the forest for the trees”.
At Pine Lake Laboratories, we have developed a standard methodology using Ion-Exchange HPLC-UV to quantitate therapeutic oligonucleotides and pegylated oligonucleotides in plasma. This methodology has been adapted and optimized for multiple compounds across a wide variety of therapeutic areas. For most compounds chromatographic resolution can be achieved between the parent compound and the N-1 to N-X metabolites. Both gradient and column temperature are important in achieving good separation. The sample preparation before HPLC analysis includes an overnight enzymatic digestion. Carryover is a common problem but a strategy of including wash injections minimizes the impact of carryover. All other validation parameters will meet the acceptance criteria. One common area for instability is for the drug in plasma at room temperature. Stability usually can be improved by keeping samples on ice during preparation or using higher concentrations of EDTA. Validated methods have been used to support GLP and human clinical studies without any method related issues. Most methods have column lives that exceed 1000 injections.
Leachables are compounds that migrate into a drug product from the sample container closure system (CCS) under normal storage condition. Leachables can enter any type of drug product including solid dosage forms. Generally, orally inhaled and nasal drug products (OINDP) and parenteral and ophthalmic drug products (PODP) are the most common drug products at high risk of leachables.
Both the primary CCS in direct contact with the drug product (metered dose inhaler, prefilled syringe, eye dropper, IV bag, HDPE bottle, LDPE ampoule, etc.) and the secondary CCS which does not contact the drug product (printed label, cardboard box, foil pouch, environmental exposure, etc.) can be sources of leachables. Leachables present a potential risk to the patient both from the toxicity of the leachable and from the possible negative impact upon stability and efficacy of the drug product. Examples of common leachables can be seen in the table below.
An exaggerated extraction study on a medical device is a forced extraction study to generate a complete extractable profile for hazard identification and is required by ISO 10993-12 to be exhaustive. An overview of the exaggerated extraction study can be found below. The key decision in study design is solvent selection. For an exaggerated extraction study, the extraction solvents are selected based upon the anticipated tissues the device will encounter. The extraction type is based on the solvent type and the analytical methods for analysis of extractables are the same for all extractions. For exaggerated extractions, the extraction must be proven to be exhaustive, therefore extraction time is established experimentally. Extractables are identified by MS and quantitated against structurally similar standards.
Overview of Exaggerated Extraction Study for Medical Devices
Solvent Extraction Type Analytical Methods 1. Polar – water, phosphate buffered saline, culture media without serum
2. Non-polar – ethanol/water, ethanol/saline, dimethyl-sulfoxide.
1. Low boiling neat solvents : Soxhlett
2. Mixed solvents, buffers and high boiling neat solvents: Batch extraction with agitation or circulation
1. Volatile organic extractables by GC-MS
2. Non-volatile organic extractables by LC-MS
3. Inorganic extractables by ICP-MS (aqueous extract only)
To support microbiome research, Pine Lake Laboratories has available an assay for short chain fatty acids (acetic, butyric, and propionic acid) in feces. These targeted metabolites can be used as an indicator of microbiome activity in research subjects and as biomarkers to evaluate the effect of various pharmaceutical treatments during pre-clinical and clinical trials. The method involves extracting the short chain fatty acids from feces then analysis by direct injection GC-MS. This method has been used to support studies in both humans and multiple animal species. For more information, please see the white paper in our technical library titled “Short Chain Fatty Acid Analysis”
The FDA has finalized guidance on validation of bioanalytical methods. Differences between the draft and final guidance, which is 10 pages longer, include a re-working of the text, a new title for Section III, which was previously named “Chromatographic methods” but is now “Bioanalytical method development and validation,” and new sections on parameters of chromatographic assays (CCs) and ligand binding assays (LBAs).
“This final guidance incorporates public comments to the revised draft published in 2013 and provides recommendations for the development, validation, and in-study use of bioanalytical methods,” FDA said. “The recommendations can be modified with justification, depending on the specific type of bioanalytical method. This guidance reflects advances in science and technology related to validating bioanalytical methods.”
Pine Lake Laboratories is a GLP/GMP compliant analytical and bioanalytical contract testing laboratory. Our lab, located in Bristol, CT, is FDA registered and inspected and DEA licensed for Schedules 1 through V.
