Scientific Considerations of Pharmaceutical Solid Polymorphism in Abbreviated New Drug Applications

Purpose. This commentary is intended to provide a scientific perspective on pharmaceutical solid polymorphism in Abbreviated New Drug Applications (ANDAs). Methods. This report proposes recommendations for monitoring and controlling drug substance polymorphs and describes scientific considerations of pharmaceutical solid polymorphism in the determination of drug substance sameness. Results. It presents three decision trees for solid oral dosage forms or liquids containing undissolved drug substances to provide a process for evaluating when and how polymorphs of drug substances are monitored and controlled in ANDA submissions. Conclusions. It is scientifically concluded that differences in polymorphic composition of drug substances in generic drug products and reference-listed drugs are not directly relevant in the determination of drug substance sameness in ANDAs.     

Pharmaceutical impurities: regulatory perspective for Abbreviated New Drug Applications

Impurities in drug substances and drug products have been important regulatory issues in the Office of Generic Drugs by having significant impact on the approvability of Abbreviated New Drug Application (ANDAs). This review begins with a discussion of ANDAs and its similarity/differences with NDAs, highlighting the importance of control of pharmaceutical impurities in generic drug product development and regulatory assessment. An overview of the FDA draft guidance documents "ANDAs: Impurities in Drug Substances" and "ANDAs: Impurities in Drug Products" are provided. This introduces the identification and qualification procedures for ANDAs and approaches to the establishment of acceptance criteria for both drug substance and drug product. Case studies included in this review illustrate the proposed pathway for determination of impurities and their acceptance criteria, based upon the general principles of these guidances.     

Common Deficiencies with Bioequivalence Submissions in Abbreviated New Drug Applications Assessed by FDA

Purpose

A generic product must meet the standards established by the Food and Drug Administration (FDA) to be approved for marketing in the USA. FDA approves a generic product for marketing if it is proved to be therapeutically equivalent to the reference product. Bioequivalence (BE) between a proposed generic product and its corresponding reference product is one of the major components of therapeutic equivalence. These approvals may be delayed if the BE portion of the submission is determined to be deficient. Many of these BE deficiencies recur commonly and can be avoided.

Method

We conducted a survey of the BE submissions to abbreviated new drug applications (ANDAs) over years 2001 to 2008 to identify the most commonly occurring BE deficiencies.

Results

Recurring deficiencies are found in a majority of the ANDAs reviewed by FDA’s Division of Bioequivalence. The most common deficiencies were the two deficiencies related to dissolution (method and specifications) found in 23.3% of the applications and analytical method validation and/or report found in 16.5% of the applications. The approval of generic drugs would be greatly accelerated if these deficiencies could be avoided.KEY WORDS: ANDA, bioequivalence, common deficiency, FDA     

Applications of In Vitro–In Vivo Correlations in Generic Drug Development: Case Studies

In vitro–in vivo correlation (IVIVC) is a predictive mathematical model describing the relationship between an in vitro property and a relevant in vivo response. The main objective of an IVIVC is to serve as a surrogate for human bioequivalence (BE) studies, which may reduce the number of BE studies performed during the initial approval process as well as with certain scale-up and postapproval changes. The US Food and Drug Administration (FDA) published a regulatory guidance related to development, evaluation, and applications of IVIVC for extended-release (ER) oral dosage forms in September 1997. Despite the publication of this guidance, the deficiencies related to IVIVC are still identified by the Division of Bioequivalence in the process of Abbreviated New Drug Application (ANDA) review. Thus, the main objective of this article is to present the most commonly occurring deficiencies associated with IVIVCs via selected case studies from the ANDAs for oral ER drug products only. We searched internal FDA databases from January 1996 to December 2014 to identify the ANDAs for proposed generic oral ER drug products containing IVIVC. Only 14 ANDA submissions had IVIVC data, and most were not acceptable. Only one ANDA submission included adequate information related to IVIVC data enabling the completion of BE review within first review cycle. It is hoped that awareness of the deficiencies presented in our article would help the generic drug applicants to submit complete and appropriate information related to IVIVC data, ultimately, resulting in a more timely approval of ANDAs.KEY WORDS: bioequivalence, extended-release drug products, generics, IVIVC, SUPAC     

Regulatory aspects of modifications to innovator bronchodilator metered dose inhalers and development of generic substitutes.

Regulatory requirements for modifications to an approved innovator metered dose inhaler (pressurized MDI; USP nomenclature: inhalation aerosol) and for development of a new generic product are discussed. Although many of the requirements apply generally to MDI's, they are discussed with specific reference to albuterol. Changes to the container and closure system may impact on the dosimetry of the redesigned product, as well as upon toxicologic and chemistry, manufacturing and controls (CMC) concerns. Changes to the formulation, including the use of alternate propellants, may raise issues requiring both clinical and in vivo performance evaluation. In view of the level of interest of a number of firms in approval requirements for generic Albuterol Inhalation Aerosol products, the article discusses in considerable detail the CMC and bioequivalence requirements for a generic product. Similarities in the CMC requirements for innovator and generic products are evident. Three comparative in vivo bioequivalence tests, particle size distribution, spray pattern and plume geometry, and unit spray content, established by the Division of Bioequivalence are discussed. Similarities and differences in the in vivo requirements for innovator and generic products are evident. Differences are the result of U.S. statute, which requires safety and efficacy testing for a product approved under a new drug application (NDA), but documentation of bioequivalence for a product approved under an abbreviated new drug application (ANDA). The advantages and disadvantages of three pharmacodynamic study designs which have potential usefulness for documentation of in vivo bioequivalence are discussed.     

Critical evaluation of thioridazine bioequivalence

The phenothiazines have exhibited a history of problems associated with the bioequivalence of solid oral dosage forms. The more recent availability of chemically equivalent forms of thioridazine has raised new and interesting questions about the appropriateness of generic product interchange, even among brands that have been designated "therapeutically equivalent" by the Food and Drug Administration. The scrutiny that has accompanied the consideration of thioridazine products for inclusion into various state generic substitution formularies has offered an opportunity to examine issues involving bioequivalency in considerable detail. Specific bioequivalency concerns relate to: correct analysis of drug in biological fluids; the importance of evaluating active metabolites: single-dose vs. multiple-dose crossover studies; appropriate statistical power analysis; the "70/70" rule, and comparison of product variabilities. Examples of problems are cited to illustrate that significant questions still remain about the appropriate factors that should be used to establish bioequivalency.     

Scientific Considerations for Generic Synthetic Salmon Calcitonin Nasal Spray Products

Under the Abbreviated New Drug Application pathway, a proposed generic salmon calcitonin nasal spray is required to demonstrate pharmaceutical equivalence and bioequivalence to the brand-name counterpart or the reference listed drug. This review discusses two important aspects of pharmaceutical equivalence for this synthetic peptide nasal spray product. The first aspect is drug substance sameness, in which a proposed generic salmon calcitonin product is required to demonstrate that it contains the same active ingredient as that in the brand-name counterpart. The second aspect is comparability in product- and process-related factors that may influence immunogenicity (i.e., peptide-related impurities, aggregates, formulation, and leachates from the container/closure system). The comparability of these factors helps to ensure the product safety, particularly with respect to immunogenicity. This review also highlights the key features of in vitro and/or in vivo studies for establishing bioequivalence for a solution nasal spray containing a systemically acting salmon calcitonin.     

Toward intelligent decision support for pharmaceutical product development

Developing pharmaceutical product formulation in a timely manner and ensuring quality is a complex process that requires a systematic, science-based approach. Information from various categories, including properties of the drug substance and excipients, interactions between materials, unit operations, and equipment is gathered. Knowledge in different forms, including heuristics, decision trees, correlations, and first-principle models is applied. Decisions regarding processing routes, choice of excipients, and equipment sizing are made based on this information and knowledge. In this work, we report on the development of a software infrastructure to assist formulation scientists in managing the information, capturing the knowledge, and providing intelligent decision support for pharmaceutical product formulation.     

Product selection, bioequivalence, and therapeutic equivalence: the generic drug market

Pharmacists are continually faced with drug product selection decisions. When is a generic drug product equivalent to the innovator product and, thus, a suitable candidate for generic substitution? The FDA policy has been that only drug products that are therapeutic equivalents are candidates for product selection decisions. This paper outlines the regulatory and scientific framework for the FDA's policies and requirements for generic drug products. The history and current status of the Drug Efficacy Study Implementation (DESI) project is described. Originally begun in 1966 as a review of about 3,400 drug products, the review in mid-1983 is more than 90% complete, but its impact has already affected more than 7,000 marketed drug products. The therapeutic equivalence policy and the manner in which decisions on therapeutic equivalence are communicated are reviewed. Regulatory policies for the approval of generic drug products are reviewed and specific litigation challenging the rights of generic drug manufacturers to produce generic "look-alikes" and challenging the FDA's policy that a generic drug product is a new drug requiring an approved New Drug Application for marketing is discussed. The conclusion reached is that the evaluation of regulatory requirements and science is leading to a point where all generic drug products will be known to be safe, effective and therapeutically equivalent, and pharmacists can be optimistic about the quality of products in the generic drug market.     

Bioequivalence of generic thioridazine drug products--the FDA viewpoint

The phenothiazines are among the most widely used drugs to treat symptoms commonly associated with acute and chronic psychoses. One of the commonly prescribed compounds within this class of drugs is thioridazine, available both as a generic product as well as the innovator product, Mellaril. Each of these products is coded as bioequivalent and consequently therapeutically equivalent by the Food and Drug Administration (FDA). A recent issue of this journal contained an article that raised a number of questions concerning the bioequivalence of the generic versions of thioridazine that have been approved by the FDA. Their article was based in part on information obtained from the FDA as well as information supplied to the authors by Sandoz, Inc., the manufacturer of the original thioridazine drug product Mellaril. The FDA has reviewed its original decision of bioequivalence. Based on this reassessment, the FDA strongly rejects the assertion by the authors that several of the approved generic thioridazine products are not bioequivalent. The rationale behind the FDA decisions and the FDA's viewpoint on the bioequivalence of generic thioridazine drug products is discussed in detail.     

Crystallization and solid state properties of molecules of pharmaceutical interest

Polymorphism characterizes the ability of a molecule to crystallize in different crystallographic systems (in the case of a simple atom the term allotropy is used). This phenomenon, known for a long time, leads to significantly different physicochemical properties between the different crystalline forms. In the pharmaceutical domain, the potential polymorphism of the active substances and the excipients could affect Since most of the pharmaceutical products consist of solid dosage forms administered by the oral route, it is not surprising that studies on polymorphism have become a mandatory chapter of any pharmaceutical dossier whether it concerns a new chemical entity or a generic. In fact, beyond the polymorphism phenomenon, it is the crystallization process which deserves to be highlighted. We will show how it controls the appearance of the polymorphism and the crystalline growth which is a second feature at least as important as the polymorphism itself (external aspect of the solid particles/habit) in terms of processability and dissolution. After having recalled some thermodynamic considerations which characterize the polymorphism, we will illustrate succinctly the impact of these phenomena on some important aspects of the pharmaceutical development such as the dissolution, the bioavailability and the stability.     

Physicochemical Characterization of Iron Carbohydrate Colloid Drug Products

Iron carbohydrate colloid drug products are intravenously administered to patients with chronic kidney disease for the treatment of iron deficiency anemia. Physicochemical characterization of iron colloids is critical to establish pharmaceutical equivalence between an innovator iron colloid product and generic version. The purpose of this review is to summarize literature-reported techniques for physicochemical characterization of iron carbohydrate colloid drug products. The mechanisms, reported testing results, and common technical pitfalls for individual characterization test are discussed. A better understanding of the physicochemical characterization techniques will facilitate generic iron carbohydrate colloid product development, accelerate products to market, and ensure iron carbohydrate colloid product quality.     

Pharmaceutical Quality by Design: Product and Process Development, Understanding, and Control

PURPOSE: The purpose of this paper is to discuss the pharmaceutical Quality by Design (QbD) and describe how it can be used to ensure pharmaceutical quality. MATERIALS AND METHODS: The QbD was described and some of its elements identified. Process parameters and quality attributes were identified for each unit operation during manufacture of solid oral dosage forms. The use of QbD was contrasted with the evaluation of product quality by testing alone. RESULTS: The QbD is a systemic approach to pharmaceutical development. It means designing and developing formulations and manufacturing processes to ensure predefined product quality. Some of the QbD elements include: Defining target product quality profile; Designing product and manufacturing processes; Identifying critical quality attributes, process parameters, and sources of variability; Controlling manufacturing processes to produce consistent quality over time. CONCLUSIONS: Using QbD, pharmaceutical quality is assured by understanding and controlling formulation and manufacturing variables. Product testing confirms the product quality. Implementation of QbD will enable transformation of the chemistry, manufacturing, and controls (CMC) review of abbreviated new drug applications (ANDAs) into a science-based pharmaceutical quality assessment.     

Effect of food and tablet age on relative bioavailability and pharmacodynamics of two tolbutamide products

Relative bioavailability and pharmacodynamics of tolbutamide from two different commercially available tablet products have been evaluated in healthy subjects in a single-dose crossover study. "Fresh" tablets and tablets aged by exposure to 98% relative humidity for 3 d at ambient temperature were studied. Aging was found to differentially affect both the rate and extent of absorption for the two products. Differences were reflected by log AUC (generic product AUC 10% lower than the product of the innovator, p = 0.047), peak concentration (generic product 27% lower than the product of the innovator, p = 0.0001), mean absorption time (generic product 119% longer than the product of the innovator, p = 0.0008), and mean residence time (generic product 17% longer than the product of the innovator, p = 0.011). Aged product from the innovator produced statistically significantly higher serum tolbutamide concentrations for the first 8 h postdose and a greater glucose depression than aged generic product. Administration of unaged tablets with food produced differences in the rate of absorption, manifested in time-to-peak (generic product 69% later than the product of the innovator, p = 0.006), peak concentration (generic product 18% lower than the product of the innovator, p = 0.001), and mean absorption time (generic product 104% greater than the product of the innovator, p = 0.007), which resulted in statistically significantly higher tolbutamide concentrations for the product of the innovator than for the generic product for the first 3 h postdose.(ABSTRACT TRUNCATED AT 250 WORDS)     

International harmonization of bioequivalence studies and issues shared in common

In the course of a review of the current health insurance system in Japan, promotion of the use of generic products of lower price is expected in direction for minifying the drug costs which occupy about 20% thereof. However, the use of generic products has not increased so much as expected. One of the reasons to explain the fact might be that concerns exist about switchability from an innovator product to a generic product or among generic products because of bias in bioequivalence. Namely, hesitation about the difference in quality between generic products and innovator products, particularly in bioequivalence due to differences in the manufacturing process and pharmaceutical technology, exists among professionals in medical practice. The bioequivalence study to guarantee that a generic product is bioequivalent to an innovator product in terms of effectiveness and safety is most important in assuring the quality of generic products. There are various specifications and study methods to prove bioequivalence which differ slightly from one to another in different countries. We have investigated bioequivalence studies which are conducted in the major countries. Consequently, we clarified that bioequivalence studies are in international harmonization in terms of the major portions thereof. However, different conditions, e.g., selection of subjects, food effect, application of multiple dose study, and in vitro dissolution study, are still employed for the studies. Therefore, we consider that these differences constitute the topics to be reviewed in future.     

欧盟仿制药参比制剂检索与确认简介（英文）

参比制剂的选择是仿制药开发和研究的一个重要环节。国家食品药品监督管理总局相关公告明确了用于仿制药质量与疗效一致性评价或仿制药申请时的参比制剂应为原研药品或国际公认的同种药物。为了帮助国内外仿制药企业正确检索和确定欧盟的参比制剂,本文详细介绍了欧盟药品的四种审评方式及相应的上市产品目录。同时以检索仿制药米非司酮片(200mg)在欧盟上市申请时须选用的参比制剂为例,结合不同的上市产品目录详细介绍了检索和确定欧盟仿制药的参比制剂过程。     

Generic maintenance immunosuppression in solid organ transplant recipients

Survival after solid organ transplantation has increased in the era of tacrolimus and mycophenolate. This increased survival could be due in part to the broad clinical use of these potent and specific agents for maintenance immunosuppression. These drugs have enhanced specificity and potency for T and B lymphocytes compared with their predecessors, cyclosporine and azathioprine. Between 2008 and 2010, the United States Food and Drug Administration approved several generic formulations of both tacrolimus and mycophenolate mofetil. Deciding whether generic products can be safely substituted for the innovator product is a clinical dilemma similar to that which occurred when generic formulations of cyclosporine became available. We describe the concerns regarding generic immunosuppression use, summarize expert opinion and consensus statements in transplantation, analyze the potential impact of generic substitution, and provide estimates of populations affected based on generic drug market penetration. Formulary considerations such as cost, availability, and potential drug ordering and drug selection errors are described, and transplant coordinator and patient perspectives are reviewed. Finally, general recommendations about the use of generic maintenance immunosuppression in solid organ transplant recipients are provided. Although more research is needed to confirm clinical and therapeutic equivalence and pharmacoeconomic benefit, generic immunosuppressants can be safely substituted for innovator products as long as patients consistently receive the same product, patients and clinicians are aware of when substitutions occur, and enhanced therapeutic drug monitoring is provided during the transition.     

Completeness Assessment of Type II Active Pharmaceutical Ingredient Drug Master Files under Generic Drug User Fee Amendment: Review Metrics and Common Incomplete Items

Under the Generic Drug User Fee Amendments (GDUFA) of 2012, Type II active pharmaceutical ingredient (API) drug master files (DMFs) must pay a user fee and pass a Completeness Assessment (CA) before they can be referenced in an Abbreviated New Drug Application (ANDA), ANDA amendment, or ANDA prior approval supplement (PAS). During the first year of GDUFA implementation, from October 1, 2012 to September 30, 2013, approximately 1,500 Type II API DMFs received at least one cycle of CA review and more than 1,100 Type II DMFs were deemed complete and published on FDA’s “Available for Reference List”. The data from CA reviews were analyzed for factors that influenced the CA review process and metrics, as well as the areas of DMF submissions which most frequently led to an incomplete CA status. The metrics analysis revealed that electronic DMFs appear to improve the completeness of submission and shorten both the review and response times. Utilizing the CA checklist to compile and proactively update the DMFs improves the chance for the DMFs to pass the CA in the first cycle. However, given that the majority of DMFs require at least two cycles of CA before being deemed complete, it is recommended that DMF fees are paid 6 months in advance of the ANDA submissions in order to avoid negatively impacting the filling status of the ANDAs.