Freeze-Drying

This completely updated and enlarged third edition of the classic text adopts a practical approach to describe the fundamentals of freeze-drying, backed by many explanatory examples.
Following an introduction to the fundamentals, the book goes on to discuss process and plant automation as well as methods to transfer pilot plant qualifications and process data to production. An entire section is devoted to a large range of different pharmaceutical, biological, and medical products. New to this edition are chapters on antibodies, freeze-dry microscopy, TEMPRIS, microwave freeze-drying, spray freeze-drying, and PAT.
Their many years of experience in freeze-drying enable the authors to supply valuable criteria for the selection of laboratory, pilot and production plants, discussing the advantages, drawbacks and limitations of different plant designs. Alongside guidelines for the evaluation and qualification of plants and processes, the author also includes a troubleshooting section.


Table of Contents:

Contents

Preface to Third Edition and Acknowledgment ix

Preface to the Second Edition xi

1 Foundations and Process Engineering 1

1.1 Freezing 2

1.1.1 Amount of Heat, Heat Conductivity, Heat Transfer, and Cooling Rate 3

1.1.2 Structure of Ice, Solutions, and Dispersions 14

1.1.3 Influence of Excipients 22

1.1.4 Freezing of Cells and Bacteria 32

1.1.5 Methods of Structure Analysis 34

1.1.5.1 Measurements of Electrical Resistance (ER) 34

1.1.5.2 Differential Thermal Analysis (DTA) 45

1.1.5.3 Cryomicroscopy 51

1.1.5.4 Freeze-Dry Microscopy 59

1.1.5.5 Differential Scanning Calorimetry (DSC) 60

1.1.5.6 Nuclear Magnetic Resonance 68

1.1.5.7 Thermomechanical Analysis (TMA) 74

1.1.5.8 Dielectric Analysis (DEA) 76

1.1.5.9 XRPD Diffractometer–Raman Spectroscopy 77

1.1.6 Changes of Structure in Freezing or Frozen Products 78

1.2 Drying 79

1.2.1 Main Drying (Sublimation Drying) 82

1.2.2 Secondary Drying (Desorption Drying) 101

1.2.3 Temperature and Pressure Measurement 113

1.2.3.1 Wireless Temperature Measurement 135

1.2.4 Water Vapor Transport during Drying 136

1.2.4.1 Endpoint Determination of Main and Secondary Drying 144

1.2.5 Collapse and Recrystallization 145

1.2.6 Drying Processes without Vacuum 148

1.2.7 Microwave Freeze-Drying 149

1.2.8 Spray Freeze-Drying 150

1.3 Storage 150

1.3.1 Measurement of the Residual Moisture Content (RM) 151

1.3.1.1 Gravimetric Method 151

1.3.1.2 Karl Fischer (KF) Method 151

1.3.1.3 Thermogravimetry (TG, TG/MS) 153

1.3.1.4 Infrared Spectroscopy 154

1.3.2 Influence of Vial Stoppers on the Residual Moisture Content 156

1.3.3 Qualities of the Dry Substances and Their Changes 162

References 165

2 Installation and Equipment Technique 177

2.1 Freezing Installation 177

2.1.1 Cooling by Liquids: Shell-Freezing and Spin-Freezing 177

2.1.2 Cooled Surfaces 178

2.1.3 Product in the Flow of Cold Air, Foaming, and Freezing of Extracts and Pulps 179

2.1.4 Droplet Freezing in Cold Liquids 181

2.1.5 Freezing by Evaporation of Product Water 184

2.1.6 Nucleation-on-Demand Technology – ControLyoTM 184

2.2 Components of a Freeze-Drying Plant 185

2.2.1 Installations for Flasks and Manifolds 185

2.2.2 Drying Chambers and Forms of Trays 186

2.2.3 Shelves and Their Cooling and Heating 192

2.2.4 Water Vapor Condensers 192

2.2.5 Refrigerating Systems and Refrigerants 201

2.2.6 Vacuum Pumps 215

2.2.7 Inlet Venting Filters 221

2.2.8 Vacuum Measuring Systems 224

2.2.9 Leak Rate Detection 229

2.2.10 Process Control Systems 232

2.2.11 Problems, Failures, and Deviations 235

2.3 Installations Up to 10 kg Ice Capacity 238

2.3.1 Universal Laboratory Plants 238

2.3.2 Pilot Plants 240

2.3.3 Manipulators and Stoppering Systems for Vials 244

2.3.4 Cleaning Installations, Sterilization by Steam, and Vaporized Hydrogen Peroxide (VHP®) 248

2.4 Production Plants 264

2.4.1 Loading and Unloading Systems 269

2.4.2 What Is an Isolator? 274

2.4.3 Isolators: Validation of Decontamination Processes 280

2.5 Production Plants for Food 283

2.5.1 Discontinuous Plants 283

2.5.2 Continuous Plants with Tray Transport 284

2.5.3 Continuous Plants with Product Transport by Wipers or by Vibration 285

2.6 Process Automation 287

2.6.1 Prerequisites for Process and Related Plant Automation 287

2.6.2 Control of the Process and Related Plant Data by Thermodynamic Data Measured during the Process: Thermodynamic Lyophilization Control (TLC) 289

2.6.2.1 Control of the Process without Temperature Sensors in the Product 289

2.6.2.2 Measurement of the Ice Temperature at the Sublimation Front and the Desorption Rate as Process Guides 292

2.6.2.3 Measurement of the Residual Moisture Content (RM) during the Process 302

2.6.2.4 The Transfer of a Freeze-Drying Process from a Pilot to a Production Plant 304

2.6.2.5 Summary of Prerequisites, Limits, and Suggestions for Automated Thermodynamic Lyophilization Control 308

References 309

Further Reading 310

3 Pharmaceutical, Biological, and Medical Products 313

3.1 Proteins and Hormones 313

3.2 Viruses, Vaccines, Bacteria, and Yeasts 330

3.3 Antibiotics, Cytostatics, Ibuprofen 341

3.4 Liposomes and Nanoparticles 342

3.5 Antibody 350

3.6 Transplants, Collagen 351

3.7 Freeze-Drying Subject Terms – Overview and Summary 358

References 360

4 Metal Oxides, Ceramic Powders 367

References 372

5 Trouble Shooting 375

5.1 Prolonged Evacuation Time 375

5.2 Sublimation Front Temperature Too High 376

5.3 Sublimation Front Temperature Irregular 376

5.4 Slow Pressure Increase in the Chamber during Main Drying 376

5.5 Stoppers ›Pop Out‹ or Slide into the Vials 377

5.6 Traces of Highly Volatile Solvents (Acetone, Ethanol) 377

5.7 Different Structures of the Dried Product in the Center and Border of a Shelf 378

6 Regulatory Issues 379

Qualification and Validation of Processes and Installations 379

6.1 PAT (Practical Analytical Technology) 385

6.2 Quality of the Product 388

6.3 Description of the Process Developed for Manufacturing of the Product 389

6.4 Description of Production Installations and Their Handling 391

6.5 Equipment Performance Tests 392

6.6 Quality of Installation to Document the Ability of Equipment to Operate Processes (Described in Section 6.3) 395

6.7 Documentation of the Quality of the Products Manufactured (in Comparison with Section 6.2) 396

References 396

Appendix: Abbreviations, Symbols, and Unit of Measure 399

Index 405