Aikaterini Avzoti, National and Kapodistrian University of Athens, Greece

Abdulwahab Barakat, PHAST Development GmbH & Co. KG, Konstanz, Germany

Jennifer Dressman, Goethe University, Frankfurt/Main, Germany

Susan D´Souza, Sunovion Pharmaceuticals Inc., Marlborough, MA, USA

Nikoletta Fotaki, Department of Pharmacy and Pharmacology, University of Bath, Bath, UK

Jayachandar Gajendran, PHAST Development GmbH & Co. KG, Konstanz, Germany

Vivian A. Gray, V. A. Gray Consulting, Inc., Hockessin, DE, USA

Alexis Guillot, PHAST Development GmbH & Co. KG, Konstanz, Germany

Murat Kilic, Goethe University, Frankfurt/Main, Germany

Sandra Klein, University of Greifswald, Germany

Johannes Krämer, DISSO GmbH, Homburg, Germany

Annalisa Mercuri, Aptuit, Evotec Company, Verona, Italy

Christos Reppas, National and Kapodistrian University of Athens, Greece

Anne Seidlitz, University of Greifswald, Germany

Christian Simroth‐Loch, University of Greifswald, Germany

Kailas Thakker, Tergus Pharma LLC, Durham NC, USA

Katharina Tietz, University of Greifswald, Greifswald, Germany

Werner Weitschies, University of Greifswald, Greifswald, Germany

Clive G. Wilson, University of Strathclyde, Glasgow, UK

The series Advances in Pharmaceutical Technology covers the principles, methods and technologies that the pharmaceutical industry uses to turn a candidate molecule or new chemical entity into a final drug form and hence a new medicine. The series will explore means of optimizing the therapeutic performance of a drug molecule by designing and manufacturing the best and most innovative new formulations. The processes associated with the testing of new drugs, the key steps involved in the clinical trials process and the most recent approaches utilized in the manufacture of new medicinal products will all be reported. The focus of the series will very much be on new and emerging technologies and the latest methods used in the drug development process.

The topics covered by the series include the following:

Formulation: The manufacture of tablets in all forms (caplets, dispersible, fast‐melting) will be described, as will capsules, suppositories, solutions, suspensions and emulsions, aerosols and sprays, injections, powders, ointments and creams, sustained release and the latest transdermal products. The developments in engineering associated with fluid, powder and solids handling, solubility enhancement, colloidal systems including the stability of emulsions and suspensions will also be reported within the series. The influence of formulation design on the bioavailability of a drug will be discussed and the importance of formulation with respect to the development of an optimal final new medicinal product will be clearly illustrated.

Drug Delivery: The use of various excipients and their role in drug delivery will be reviewed. Among the topics to be reported and discussed will be a critical appraisal of the current range of modified‐release dosage forms currently in use and also those under development. The design and mechanism(s) of controlled release systems including macromolecular drug delivery, microparticulate controlled drug delivery, the delivery of biopharmaceuticals, delivery vehicles created for gastrointestinal tract targeted delivery, transdermal delivery and systems designed specifically for drug delivery to the lung will all be reviewed and critically appraised. Further site‐specific systems used for the delivery of drugs across the blood–brain barrier including dendrimers, hydrogels and new innovative biomaterials will be reported.

Manufacturing: The key elements of the manufacturing steps involved in the production of new medicines will be explored in this series. The importance of crystallization; batch and continuous processing, seeding; and mixing including a description of the key engineering principles relevant to the manufacture of new medicines will all be reviewed and reported. The fundamental processes of quality control including good laboratory practice, good manufacturing practice, Quality by Design, the Deming Cycle, regulatory requirements and the design of appropriate robust statistical sampling procedures for the control of raw materials will all be an integral part of this book series.

An evaluation of the current analytical methods used to determine drug stability, drug dissolution and release, the quantitative identification of impurities, contaminants and adulterants in pharmaceutical materials will be described, as will the production of therapeutic bio‐macromolecules, bacteria, viruses, yeasts, molds, prions and toxins through chemical synthesis and emerging synthetic/molecular biology techniques. The importance of packaging including the compatibility of materials in contact with drug products and their barrier properties will also be explored.

Advances in Pharmaceutical Technology is intended as a comprehensive one‐stop shop for those interested in the development and manufacture of new medicines. The series will appeal to those working in the pharmaceutical and related industries, both large and small, and will also be valuable to those who are studying and learning about the drug development process and the translation of those drugs into new life‐saving and life‐enriching medicines.

In the mid‐1960s people realized that drug dissolution/release has a significant impact on the therapeutic effect of orally administered drugs. Both the United States Food and Drug Administration (FDA) and United States Pharmacopeia introduced dissolution requirements for oral drug products and the first dissolution tests became a quality control (QC) tool to ensure batch‐to‐batch consistency. As a consequence, from the 1970s on, several dissolution test methods were adopted as official QC methods for solid oral dosage forms. In the late 1990s, the increasing number of official dissolution apparatus and dissolution methods in the USP was complemented by the release of various FDA guidances pertaining to in vitro dissolution testing of solid oral dosage forms and its application from a regulatory point of view. Since then, dissolution/drug release testing has expanded considerably, with a variety of apparatus and methods in international pharmacopoeias and numerous international guidances, and nowadays not only addresses questions of QC but also plays an important role in screening of formulations and is also an important tool in proving bioequivalence of different drug products.

In the last decade application of drug release testing has widened to a variety of novel or special dosage forms where it is used for the same purposes. Because of the complexity of specialized dosage forms, a “one fits all” approach is not possible. Moreover, particularly in order to predict the in vivo behavior of such dosage forms, the design of the test methods need to take into account various aspects, including the dosage form design and the conditions at the site of application and/or the site of drug release. Even though a number of special dosage forms are on the market, there is less known about how to design an adequate test method.

In Vitro Drug Release Testing of Special Dosage Forms focuses on the description and discussion of state‐of‐the‐art drug release methodologies to evaluate the key performance of special dosage forms. The book consists of two sections that address both the design and development of compendial and biorelevant dissolution methods. It begins with two chapters devoted to special types of orally administered dosage forms that may require in vitro test setups other than those applied for solid oral dosage forms with immediate or modified release in the gastrointestinal tract. Chapters 3–9 set the focus on compendial and biorelevant performance testing of non‐oral dosage forms and provide a detailed discussion of what is the status of dissolution/drug release methods for this quite heterogenous group of dosage forms, what would be typical requirements for a QC test and what should be the essential features of an in vitro test that can be applied to predict the in vivo performance of these special dosage forms. The last chapter of the book is devoted to regulatory aspects and summarizes the regulatory and compendial documents that relate to in vitro dissolution/drug release testing and discusses the role of method development in setting clinically relevant specifications for novel/special dosage forms.

This book should be the first point of call for anyone starting in the field of in vitro release testing of special dosage forms, as well as those already familiar with this topic, by providing the most recent updates on the field.

We would like to thank all authors for taking the time to share their experiences and contributing a chapter to this book, which allowed us to produce a book that reflects the current status and state‐of‐the‐art thinking in in vitro drug release testing of novel/special dosage forms. Further, we would like to thank the editors at John Wiley & Sons Limited for their continuous support.

Finally, we hope that the information in this book can contribute to efforts in designing and optimizing in vitro methods for determining drug release from special dosage forms.