Biocompatibility Considerations for Orally Inhaled and Nasal Drug Products and Other Drug--Device Combination Products.

Biocompatibility considerations have historically been important for orally inhaled and nasal drug products (OINDPs) and other drug-device combination products, because finished device components and packaging in these products are often in direct contact with formulation and the patient. The International Pharmaceutical Aerosol Consortium on Regulation and Science (IPAC-RS) discusses, in this article, the current regulatory landscape associated with biocompatibility and how biocompatibility is typically assessed for OINDPs, including risk management considerations and navigation of regulatory requirements. The article also describes current challenges related to alignment of regulatory expectations, particularly for drug-device combination products, and proposes some questions and topics for further discussion with regulatory agencies and other stakeholders to help advance alignment. To further illustrate current challenges and industry approaches to meeting biocompatibility requirements, we also present results of an IPAC-RS benchmarking survey and case studies.

Challenges Associated with Biological Safety Assessments for Drug-Device Combination Products.

Biological safety assessments for drug-device combination products involve evaluation of the drug container closure and the device constituent part. When the device constituent part is the drug delivery system as well as the drug container closure system, both device and drug-based packaging standards have been deemed applicable. Approaches used for the biological safety assessment of medical devices differ from those used for pharmaceutical packaging/delivery systems. One area of difference is the extent to which chemical characterization with toxicological assessment is used either in addition to, or in place of, biological in vivo or in vitro tests. Differences also exist in the way nonclinical studies are used to evaluate the safety of medical devices or drug delivery systems. The lack of alignment in standards and guidance has resulted in confusion over what combination of tests and methods of evaluation constitute a biological safety assessment that will meet regulatory expectations for a drug-device combination product. The intent of this article is to discuss the challenges created when the packaging or delivery system is also a device constituent part of a drug-device combination product. Suggestions are offered regarding approaches that may be useful for conducting suitable biological safety assessments for drug-device combination products.

An Overview and Discussion of N-nitrosamine Considerations for Orally Inhaled Drug Products and Relevance to Other Dosage Forms.

The presence of N-nitrosamines in drug products are currently an area of high regulatory and industry scrutiny, having been detected above acceptable regulatory levels in several solid oral drug products. For over 20 years, there has been an expectation that N-nitrosamines be eliminated or controlled to acceptable levels in orally inhaled and nasal drug products (OINDP). As a result, the OINDP industry has developed and implemented risk management processes and considerations to address N-nitrosamines in final drug product, including management and understanding of upstream supply particularly for OINDP device and container closure systems. We provide an overview of N-nitrosamine formation, discuss key current regulatory expectations worldwide for N-nitrosamines in drug products, discuss risk management approaches relevant for drug device combination products, and share analytical "tips" with respect to handling N-nitrosamines chemical assessments.

Considerations when deriving compound-specific limits for extractables and leachables from pharmaceutical products: Four case studies.

Leachables from pharmaceutical container closure systems are a subset of impurities that present in drug products and may pose a risk to patients or compromise product quality. Extractable studies can identify potential leachables, and extractables and leachables (E&Ls) should be evaluated during development of the impurity control strategy. Currently, there is a lack of specific regulatory guidance on how to risk assess E&Ls; this may lead to inconsistency across the industry. This manuscript is a cross-industry Extractables and Leachables Safety Information Exchange (ELSIE) consortium collaboration and follow-up to Broschard et al. (2016), which aims to provide further clarity and detail on the conduct of E&L risk assessments. Where sufficient data are available, a health-based exposure limit termed Permitted Daily Exposure (PDE) may be calculated and to exemplify this, case studies of four common E&Ls are described herein, namely bisphenol-A, butylated hydroxytoluene, Irgafos® 168, and Irganox® 1010. Relevant discussion points are further explored, including the value of extractable data, how to perform route-to-route extrapolations and considerations around degradation products. By presenting PDEs for common E&L substances, the aim is to encourage consistency and harmony in approaches for deriving compound-specific limits.

Assessing safety of extractables from materials and leachables in pharmaceuticals and biologics - Current challenges and approaches.

Leachables from pharmaceutical container closure systems can present potential safety risks to patients. Extractables studies may be performed as a risk mitigation activity to identify potential leachables for dosage forms with a high degree of concern associated with the route of administration. To address safety concerns, approaches to toxicological safety evaluation of extractables and leachables have been developed and applied by pharmaceutical and biologics manufacturers. Details of these approaches may differ depending on the nature of the final drug product. These may include application, the formulation, route of administration and length of use. Current regulatory guidelines and industry standards provide general guidance on compound specific safety assessments but do not provide a comprehensive approach to safety evaluations of leachables and/or extractables. This paper provides a perspective on approaches to safety evaluations by reviewing and applying general concepts and integrating key steps in the toxicological evaluation of individual extractables or leachables. These include application of structure activity relationship studies, development of permitted daily exposure (PDE) values, and use of safety threshold concepts. Case studies are provided. The concepts presented seek to encourage discussion in the scientific community, and are not intended to represent a final opinion or "guidelines."

Materials in Manufacturing and Packaging Systems as Sources of Elemental Impurities in Packaged Drug Products: A Literature Review.

Elemental impurities in drug products can arise from a number of different sources and via a number of different means, including the active pharmaceutical ingredient, excipients, the vehicle, and leaching of elemental entities that are present in the drug product's manufacturing or packaging systems. Thus, knowledge about the presence, level, and likelihood of leaching of elemental entities in manufacturing and packaging systems is relevant to understanding how these systems contribute to a drug product's total elemental impurity burden. To that end, a joint team from the Extractables and Leachables Safety Information Exchange (ELSIE) Consortium and the International Pharmaceutical Aerosol Consortium on Regulation and Science (IPAC-RS) has conducted a review of the available literature on elemental entities in pharmaceutically relevant polymers and the presence of these elemental entities in material extracts and/or drug products. This review article contains the information compiled from the available body of literature and considers two questions: (1) What elemental entities are present in the relevant polymers and materials and at what levels are they present? (2) To what extent are these elemental entities leached from these materials under conditions relevant to the manufacturing and storage/distribution of solution drug products? Conclusions drawn from the compiled data are as follows: (1) Elemental entities are present in the materials used to construct packaging and manufacturing systems as these materials either contain these elemental entities as additives or are exposed to elemental entities during their production. (2) Unless the elemental entities are parts of the materials themselves (for example, SiO2 in glass) or intentionally added to the materials (for example, metal stearates in polymers), their incidental amounts in the materials are generally low. (3) When elemental entities are present in materials and systems, generally only a very small fraction of the total available amount of the entity can be leached under conditions that are relevant to packaged drug products. Thus, while sources of certain elemental impurities may be ubiquitous in the natural environment, they are not ubiquitous in materials used in pharmaceutical packaging and manufacturing systems and when they are present, they are not extensively leached under relevant conditions. The information summarized here can be utilized to aid the elemental impurity risk assessment process by providing the identities of commonly reported elements and data to support probability estimates of those becoming elemental impurities in the drug product. Furthermore, recommendations are made related to establishing elements of potential product impact for individual materials. LAY ABSTRACT: Extraneous impurities in drug products provide no therapeutic benefit and thus should be known and controlled. Elemental impurities can arise from a number of sources and by a number of means, including the leaching of elemental entities from drug product packaging and manufacturing systems. To understand the extent to which materials used in packaging systems contain elemental entities and the extent to which those entities leach into drug products to become elemental impurities, the Extractables and Leachables Safety Information Exchange (ELSIE) and International Pharmaceutical Aerosol Consortium on Regulation and Science (IPAC-RS) Consortia have jointly performed a literature review on this subject. Using the compiled information, it was concluded that while packaging materials may contain elemental entities, unless those entities are intentional parts of the materials, the amounts of those elemental entities are generally low. Furthermore, generally only a very small fraction of the total available amount of the entity can be leached under conditions that are relevant to packaged drug products. Thus, risk assessment of sources of elemental impurities in drug products that may be related to materials used in pharmaceutical packaging and manufacturing systems can utilize the information and recommendations presented here.

Evaluation of extractables in processed and unprocessed polymer materials used for pharmaceutical applications.

Polymeric materials are often used in pharmaceutical packaging, delivery systems, and manufacturing components. There is continued concern that chemical entities from polymeric components may leach into various dosage forms, particularly those that are comprised of liquids such as parenterals, injectables, ophthalmics, and inhalation products. In some cases, polymeric components are subjected to routine extractables testing as a control measure. To reduce the risk of discovering leachables during stability studies late in the development process, or components that may fail extractables release criteria, it is proposed that extractables testing on polymer resins may be useful as a screening tool. Two studies have been performed to evaluate whether the extractables profile generated from a polymer resin is representative of the extractables profile of components made from that same resin. The ELSIE Consortium pilot program examined polyvinyl chloride and polyethylene, and another study evaluated polypropylene and a copolymer of polycarbonate and acrylonitrile butadiene styrene. The test materials were comprised of polymer resin and processed resin or molded components. Volatile, semi-volatile, and nonvolatile chemical profiles were evaluated after headspace sampling and extraction with solvents of varying polarity and pH. The findings from these studies indicate that there may or may not be differences between extractables profiles obtained from resins and processed forms of the resin depending on the type of material, the compounds of interest, and extraction conditions used. Extractables testing of polymer resins is useful for material screening and in certain situations may replace routine component testing.

Controlled Extraction Studies Applied to Polyvinyl Chloride and Polyethylene Materials: Conclusions from the ELSIE Controlled Extraction Pilot Study.

The effective management of leachables in pharmaceutical products is a critical aspect of their development. This can be facilitated if extractables information on the materials used in a packaging or delivery system is available to assist companies in selecting materials that will be compatible with the drug product formulation and suitable for the intended use. The Extractables and Leachables Safety Information Exchange (ELSIE) materials working group developed and executed a comprehensive extraction study protocol that included a number of extraction solvents, extraction techniques, and a variety of analytical techniques. This was performed on two test materials, polyethylene (PE) and polyvinyl chloride (PVC), that were selected due to their common use in pharmaceutical packaging. The purpose of the study was to investigate if the protocol could be simplified such that (i) a reduced number or even a single extraction technique could be used and (ii) a reduced number of solvents could be used to obtain information that is useful for material selection regardless of product type. Results indicate that, at least for the PVC, such reductions are feasible. Additionally, the studies indicate that levels of extractable elemental impurities in the two test materials were low and further confirm the importance of using orthogonal analytical detection techniques to gain adequate understanding of extraction profiles.

A risk-based approach to management of leachables utilizing statistical analysis of extractables.

To incorporate quality by design concepts into the management of leachables, an emphasis is often put on understanding the extractable profile for the materials of construction for manufacturing disposables, container-closure, or delivery systems. Component manufacturing processes may also impact the extractable profile. An approach was developed to (1) identify critical components that may be sources of leachables, (2) enable an understanding of manufacturing process factors that affect extractable profiles, (3) determine if quantitative models can be developed that predict the effect of those key factors, and (4) evaluate the practical impact of the key factors on the product. A risk evaluation for an inhalation product identified injection molding as a key process. Designed experiments were performed to evaluate the impact of molding process parameters on the extractable profile from an ABS inhaler component. Statistical analysis of the resulting GC chromatographic profiles identified processing factors that were correlated with peak levels in the extractable profiles. The combination of statistically significant molding process parameters was different for different types of extractable compounds. ANOVA models were used to obtain optimal process settings and predict extractable levels for a selected number of compounds. The proposed paradigm may be applied to evaluate the impact of material composition and processing parameters on extractable profiles and utilized to manage product leachables early in the development process and throughout the product lifecycle.

Perspectives on the PQRI Extractables and Leachables "Safety Thresholds and Best Practices" Recommendations for Inhalation Drug Products.

In 2006, the Product Quality Research Institute's (PQRI) Leachables and Extractables Working Group released a comprehensive and detailed recommendation document related to leachables and extractables for inhalation drug products. The document includes best pharmaceutical development practice recommendations regarding container closure/delivery system component composition and selection, controlled extraction studies, drug product leachables studies, and routine extractables testing for component release. Also included in the document are two safety-based thresholds for leachables in inhalation drug products, the qualification threshold (QT) and the safety concern threshold (SCT), the first such safety-based thresholds for leachables in any drug product type. A process was described for converting the SCT into an analytically useful threshold for leachables/extractables characterization, the analytical evaluation threshold (AET), with consideration of individual drug product dosing parameters and container closure system component characteristics. This commentary presents the history and evolution of this recommendation document starting from the propellant changeover (chlorofluorocarbons to hydrofluorocarbons) in metered dose inhaler drug products, which helped prompt interest in inhalation drug product leachables, through the work process of the PQRI group. The overall positive acceptance of the PQRI recommendations is discussed, along with a brief summary of regulatory initiatives influenced by the recommendations. Also presented and discussed are certain key issues and questions that have arisen since the recommendation document was released. The extension and application of best practice recommendations to other high risk drug product types (e.g., large and small volume parenterals, ophthalmics), led by the PQRI Parenteral and Ophthalmic Drug Product Working Group, is introduced and considered. LAY ABSTRACT: The recommendation document released by the Product Quality Research Institute's (PQRI) Leachables and Extractables Working Group in 2006 includes the first safety-based thresholds for leachables in any drug product type, along with comprehensive best practice recommendations for inhalation drug product pharmaceutical development related to extractables and leachables. The best practice recommendations encompass a number of important functional areas, including container closure/delivery system component composition and selection, controlled extraction studies, drug product leachables studies, and routine extractables testing for component release. This commentary presents the history and evolution of this recommendation document starting from the propellant changeover (chlorofluorocarbons to hydrofluorocarbons) in metered dose inhaler drug products, which helped prompt interest in inhalation drug product leachables, through the work process of the PQRI group. The overall positive acceptance of the PQRI recommendations is discussed, along with a brief summary of regulatory initiatives influenced by the recommendations. Also presented and discussed are certain key issues and questions that have arisen since the recommendation document was released. The extension and application of best practice recommendations to other drug product types (e.g., large- and small-volume parenterals, ophthalmics), led by the PQRI Parenteral and Ophthalmic Drug Product Working Group, is introduced and considered.

Trileucine improves aerosol performance and stability of spray-dried powders for inhalation.

For particles to be useful medicinal aerosols, not only their aerodynamic diameter has to be on the order of a few micrometers but also they have to be chemically and physically stable. Manufacture of respirable particles is a technical challenge because as particles are reduced in size by conventional milling techniques, their cohesiveness greatly increases and physical and chemical stability is often compromised by the formation of amorphous material. In the present study, we describe the use of trileucine for the preparation of dry powders suitable for inhalation via spray drying of a wide range of drugs (i.e., asthma therapeutics such as albuterol and cromolyn, and anti-infectives such as netilmicin and gentamicin, as well as therapeutic proteins and peptides such as human growth hormone and salmon calcitonin). The glass transition of spray-dried trileucine is dependent on the pH and can be correlated with the proportion of the anion, cation, and zwitterion concentration in solution. Trileucine glass transition is relatively high ( approximately 104 degrees C) enabling long-term room temperature stability. The solubility of trileucine is dependent on the pH and is lowest at neutral pH ( approximately 6.8 mg/mL). Trileucine's low aqueous solubility enables the formation of low-density corrugated particles and promotes the formation of trileucine coated spray-dried particles, resulting in superior aerosol performance. Trileucine is surface active and promotes the formation of spray-dried powders with a reduced cohesiveness as demonstrated by a decrease in the measured surface energy which correlates with an observed improvement in aerosol performance. Additionally, trileucine competes with the protein on the air/water interface resulting in an additional depression of surface tension in solution which correlates with a decreased denaturation and aggregation in the solid state.