Nanoemulsions : Formulation, Applications, and Characterization

Nanoemulsions: Formulation, Applications, and Characterization provides detailed information on the production, application and characterization of food nanoemulsion as presented by experts who share a wealth of experience. Those involved in the nutraceutical, pharmaceutical and cosmetic industries will find this a useful reference as it addresses findings related to different preparation and formulation methods of nanoemulsions and their application in different fields and products. As the last decade has seen a major shift from conventional emulsification processes towards nanoemulsions that both increase the efficiency and stability of emulsions and improve targeted drug and nutraceutical delivery, this book is a timely resource. Summarizes general aspects of food nanoemulsions and their formulation Provides detailed information on the production, application, and characterization of food nanoemulsion Reveals the potential of nanoemulsions, as well as their novel applications in functional foods, nutraceutical products, delivery systems, and cosmetic formulations Explains preparation of nanoemulsions by both low- and high-energy methods Front Cover Inside Front Cover Nanoemulsions: Formulation, Applications, and Characterization Copyright Contents Contributors Preface Part I: Nanoemulsion Basics Chapter 1: General Aspects of Nanoemulsions and Their Formulation 1.1. Introduction 1.2. Structure of Nanoemulsions 1.3. Nanoemulsion Fabrication 1.4. Nanoemulsion Particle Properties 1.5. Nanoemulsion Stability 1.6. Nanoemulsion Ingredients 1.7. Physicochemical Properties of Nanoemulsions 1.8. Nanoemulsion Characterization 1.9. Applications of Nanoemulsions 1.10. Conclusion References Chapter 2: Overview of Nanoemulsion Properties: Stability, Rheology, and Appearance 2.1. Introduction 2.2. Importance of Physicochemical Properties 2.2.1. General Physicochemical Properties of Nanoemulsions 2.2.2. Importance of Physicochemical Properties 2.2.2.1. Stability 2.2.2.2. Appearance 2.2.2.3. Rheology 2.2.2.4. Release Characteristics 2.2.3. Structure-Function Relationships 2.2.3.1. Droplet Composition 2.2.3.2. Droplet Concentration 2.2.3.3. Droplet Size 2.2.3.4. Droplet Charge 2.2.3.5. Physical State of the Droplets 2.3. Stability 2.3.1. Gravitational Separation 2.3.2. Droplet Aggregation 2.3.3. Ostwald Ripening 2.3.4. Chemical Stability 2.4. Rheological Properties 2.4.1. Dilute Systems 2.4.2. Concentrated Systems 2.4.2.1. No Long-Range Colloidal Interactions 2.4.2.2. Repulsive Interactions 2.4.2.3. Attractive Interactions 2.5. Appearance 2.5.1. Measurements of Optical Properties 2.5.2. Major Factors Influencing Nanoemulsion Color 2.5.2.1. Droplet Size and Concentration 2.5.2.2. Refractive Index Contrast 2.5.2.3. Absorption Spectrum 2.6. Conclusions References Part II: Preparation of Nanoemulsions by Low-Energy Methods Chapter 3: Catastrophic Phase Inversion Techniques for Nanoemulsification 3.1. Introduction 3.2. The Role of Self-Assembly and Interfacial Properties in CPI 3.3. Describing CPI Using Phase Diagrams and Emulsification Maps 3.3.1. Phase Behavior and Its Role in Phase Inversion 3.3.2. Emulsification Maps Representing CPI 3.4. CPI Using Solid Particles 3.5. The Effect of Hydrodynamic Processing and Physicochemical Variables 3.6. Conclusions References Chapter 4: Transitional Nanoemulsification Methods 4.1. Introduction 4.2. The Role of PEGylated Nonionic Surfactants on Transitional Emulsification Methods 4.3. Transitional Emulsification Methods, Emulsion Phase Inversion, Spontaneous Emulsification, and Universality of the P ... 4.3.1. PIT Method 4.3.2. Spontaneous Emulsification and the Universality of Transitional Emulsification 4.3.3. Critical Difference Between Spontaneous Nanoemulsions and Microemulsions 4.4. Applications of Transitional Nanoemulsions for Encapsulation of Active Principle Ingredients 4.5. Conclusion References Further Reading Part III: Production of Nanoemulsions by Mechanical Methods Chapter 5: General Principles of Nanoemulsion Formation by High-Energy Mechanical Methods 5.1. Introduction 5.1.1. The Thermodynamics of Nanoemulsion Formation 5.2. Mechanical Basis for Making and Breaking Droplets 5.2.1. Drop Breakup and the Stress Balance 5.2.2. Flow Regimes: Laminar and Turbulent Flow 5.2.3. Laminar Drop Breakup—The Laminar Viscous Mechanism 5.2.4. Turbulent Drop Breakup—The Turbulent Viscous Mechanism 5.2.5. Turbulent Drop Breakup—The Turbulent Inertial Mechanism 5.2.6. The Influence of Viscosity on Turbulent Drop Breakup 5.2.7. Drop Break-Up Due to Cavitation 5.3. Dynamics of Droplet Formation and Stabilization 5.3.1. From Possible to Probable—Population Balance Modelling 5.3.2. The Rate of Fragmentation 5.3.3. The Importance of Coalescence 5.3.4. Some Additional Complications Related to Hydrodynamics 5.4. Introducing the High Energy Methods 5.4.1. Rotor-Stator Emulsification 5.4.2. High Pressure Valve Homogenization 5.4.3. Microfluidization 5.4.4. Ultrasonication 5.4.5. Membrane Emulsification 5.4.6. Comparing the High-Energy Methods 5.5. Summary and Notes on the Particularities of Nanoemulsion Formation References Further Reading Chapter 6: Fabrication of Nanoemulsions by Rotor-Stator Emulsification 6.1. Introduction 6.2. Classification of Rotor-Stator Emulsification Devices 6.2.1. Batch Devices 6.2.1.1. High-Shear Mixers 6.2.1.2. Disperser Discs 6.2.2. Continuous Devices 6.2.2.1. Gear-Rim Dispersing Units 6.2.2.2. Colloid Mills 6.3. Modes of Operation of Rotor-Stator Devices 6.4. Engineering Description of Rotor-Stator Emulsification 6.4.1. The Power Density Concept as a Tool to Scale Batch Processes 6.4.2. The Energy Density Concept as a Tool to Compare Continuous Processes 6.5. Strategies to Minimize Emulsion Droplet Sizes 6.5.1. Influence of Process Parameters 6.5.1.1. Rotational Speed 6.5.1.2. Rotor Size and Size Ratio 6.5.1.3. Rotor Design 6.5.1.4. Emulsification Time in Batch Devices 6.5.2. Influence of Formulation Parameters 6.5.2.1. Viscosity of the Continuous Phase 6.5.2.2. Viscosity of Disperse Phase 6.5.2.3. Viscosity Ratio 6.5.2.4. Disperse Phase Ratio 6.5.2.5. Emulsifier Concentration and Adsorption Kinetics 6.6. Examples of the Successful Production of Nanoemulsions in Rotor-Stator Processes 6.7. Conclusion References Chapter 7: Fabrication of Nanoemulsions by High-Pressure Valve Homogenization 7.1. Introduction 7.2. Design and Principles of Operation 7.2.1. HPH Valve Design 7.2.2. Geometry, Flowrate and Homogenizing Pressure 7.2.3. Thermodynamic Efficiency 7.2.4. One-Stage or Two-Stage Design 7.3. Drop Fragmentation and Coalescence Mechanisms 7.3.1. Three Approaches for Studying HPH Emulsification 7.3.2. Laminar Shear and the Inlet Chamber 7.3.3. Shear and Turbulence in the Gap 7.3.4. Turbulence in the Outlet Chamber 7.3.5. Cavitation 7.3.6. Coalescence During Emulsification 7.3.7. The Role of Disperse Phase Volume Fraction 7.3.8. The Role of Surfactants and Emulsifiers 7.4. Scale-up and Scale-down 7.4.1. Experimental Insights on the Effect of HPH Scale 7.4.2. Scaling, Fluid Velocity and Pressure Distribution 7.4.3. Fragmentation Mechanisms and Scale 7.4.4. Implications for Scale-up of Nanoemulsion Formation 7.5. Heat Generation and Temperature Rise 7.5.1. Local Increase in Temperature 7.5.2. Product Quality and HPH Temperature Increase 7.6. Suitability for Nanoemulsion Formation 7.6.1. Applications and Required Homogenizing Pressure 7.6.2. HPH Passages 7.6.3. Overprocessing 7.6.4. Future Perspectives on of HPH Nanoemulsion Research and Development 7.7. Conclusions and Final Remarks References Chapter 8: Fabrication of Nanoemulsions by Microfluidization 8.1. Introduction 8.2. Microfluidizer Elements 8.3. EDS Reduction by Microfluidization 8.4. Factors Influencing the Properties of Nanoemulsions Produced by Microfluidization 8.4.1. Type of Interaction Chamber 8.4.2. Single-Channel to Dual-Channel Microfluidization Method 8.4.3. Rheological Properties of Microfluidized Nanoemulsions 8.4.4. Type of Surfactant or Emulsifier 8.4.5. Recoalescence of Emulsion Droplets During Microfluidization 8.4.6. Residence Time Distributions and Energy Density 8.5. Applications and Recent Developments in Nanoemulsions Produced by Microfluidization 8.5.1. Pharmaceuticals 8.5.2. Cosmetics 8.5.3. Food 8.6. A Case Study on Production of β-Carotene Nanoemulsions by Microfluidization for Encapsulation Purposes 8.7. Conclusions References Further Reading Chapter 9: Fabrication of Nanoemulsions by Ultrasonication 9.1. Introduction 9.2. A Historical Prospective of UAE 9.3. Advantages and Disadvantages of Ultrasound Emulsification 9.4. Principles of Ultrasonic Homogenization 9.5. Recent Advances in Ultrasound Equipment Design for Nanoemulsification 9.6. Factors Affecting the Efficiency of UAE Process 9.6.1. Effect of Formulation Parameters 9.6.1.1. Type of the Dispersed Phase (Oil) 9.6.1.2. Volume Fraction of the Dispersed Phase 9.6.1.3. Type and Concentration of Surfactants and Other Stabilizers 9.6.2. Effect of Operating Parameters 9.6.2.1. Preparation Method of Coarse Emulsions 9.6.2.2. Sonication Time 9.6.2.3. Ultrasonic Applied Power 9.6.2.4. Ultrasonic Amplitude 9.6.2.5. Ultrasonic Frequency 9.6.2.6. Ultrasonic Temperature 9.7. Storage Stability and Functionality of Ultrasound-Mediated NEs 9.7.1. Physical Storage Stability 9.7.2. Chemical Storage Stability 9.7.3. Functionality of Ultrasound-Mediated NEs 9.8. Conclusion and Further Remarks References Chapter 10: Fabrication of Nanoemulsions by Membrane Emulsification 10.1. Introduction 10.2. Direct ME vs. Premix ME 10.3. Comparison Between Membrane Emulsification and Microfluidic Emulsification 10.4. Comparison Between Membrane and Conventional Homogenization 10.5. Microporous Membranes for Emulsification 10.5.1. SPG Membrane 10.5.1.1. Fabrication of SPG Membrane 10.5.1.2. Properties of SPG Membrane 10.5.1.3. Surface Modification of SPG Membrane 10.5.2. Polymeric Membranes 10.5.3. Microengineered or Microsieve Membranes 10.6. Equipment for Membrane Emulsification 10.6.1. Batch Cross-Flow Membrane Emulsification 10.6.2. Batch SPG Micro Kits 10.6.3. Membrane Extruders 10.6.4. Rotating Membrane Emulsification Systems 10.6.5. Oscillating Membrane Emulsification Systems 10.7. Prediction of Mean Drop Size in Direct ME 10.7.1. Effects of Transmembrane Pressure and Flux 10.7.2. Effects of Pore Size and Shear Stress 10.7.3. Effect of Surfactant 10.8. Factors Affecting Droplet Size in Premix ME 10.9. Microemulsions vs. Nanoemulsions 10.10. Factors Affecting Formation of Micro/Nanoemulsions via Membrane Emulsification 10.10.1. Direct Membrane Emulsification 10.10.2. Premix Membrane Emulsification 10.11. Preparation of Micro/Nanoemulsions Using Direct ME 10.12. Preparation of Nanoemulsions Using Premix ME 10.13. Production of Nanoparticles from Nanoemulsions Prepared by ME 10.13.1. Hydrogel Nanoparticles 10.13.2. Solid Lipid Nanoparticles 10.13.3. Biodegradable Polymeric Nanoparticles 10.14. Conclusions References Further Reading Part IV: Application of Nanoemulsions Chapter 11: Applications of Nanoemulsions in Foods 11.1. Introduction 11.2. Nanoemulsion Formulation for Food Applications 11.2.1. Nanoemulsion Properties on Different Length Scales 11.2.2. Formulation 11.2.3. In Product and In Body Behavior 11.3. Delivery of Bioactive Compounds 11.4. Delivery of Micronutritive Compounds 11.5. Delivery of Flavors and Colors 11.6. Product Structuring 11.7. Antimicrobial Agents 11.8. Conclusions and Perspectives References Chapter 12: Application of Nanoemulsions in Formulation of Pesticides 12.1. Introduction 12.1.1. Background of Pesticides 12.1.2. Current Problems in Application of Pesticides 12.2. Traditional Pesticide Formulations 12.2.1. Emulsifiable Concentrates 12.2.2. Microemulsions 12.2.3. Emulsions 12.3. Developments of Pesticide Nanoemulsions 12.3.1. Composition of Pesticide Nanoemulsions 12.3.2. Advantages and Disadvantages of Pesticide Nanoemulsions 12.3.3. Production of Pesticide Nanoemulsions 12.3.3.1. High-Energy Processing Method 12.3.3.2. Low-Energy Processing Method 12.4. Influencing Factors for Formation and Stability of Pesticide Nanoemulsions 12.4.1. pH Stability 12.4.2. Ionic Strength 12.4.3. Temperature 12.4.4. Oil-Water Ratio 12.4.5. Dilution Ratio 12.5. Application Performance of Pesticide Nanoemulsions 12.5.1. Deposition, Diffusion, and Pervaporation of Pesticide Nanoemulsions 12.5.1.1. Bedewing 12.5.1.2. Soaking Spreading 12.5.2. Bioactivity of Pesticide Nanoemulsions 12.6. Conclusion and Further Remarks References Chapter 13: Application of Nanoemulsions in Drug Delivery 13.1. Introduction 13.2. Drug Delivery Applications 13.2.1. Oral Delivery 13.2.2. Parenteral Delivery 13.2.3. Transdermal and Topical Delivery 13.2.4. Intranasal Delivery 13.2.5. Ocular Delivery 13.3. Nanoemulsions for Vaccine Delivery 13.4. Nanoemulsions for Gene Delivery 13.5. Conclusion and Future Prospects References Further Reading Chapter 14: Application of Nanoemulsions in Cosmetics 14.1. Introduction 14.1.1. Generalities on Nanoemulsions 14.1.2. How Nanoemulsions Meet Cosmetics Needs 14.2. Challenges for Cosmetics Nanoemulsions 14.3. Formulation Processes 14.3.1. High-Energy Process 14.3.1.1. Devices and Processes 14.3.1.2. Formulation Parameters 14.3.2. Low Energy Process 14.4. Controlling Nanoemulsion Stability and Texture 14.4.1. Stability Control 14.4.2. Textures: From Lotions to Gels 14.5. Examples of Cosmetic Applications 14.5.1. Skin Care 14.5.2. Hair Fiber and Scalp 14.5.3. Preservative System for Cosmetic Nanoemulsions 14.6. Conclusions References Further Reading Chapter 15: Application of Nanoemulsions in the Synthesis of Nanoparticles 15.1. Introduction 15.1.1. Definitions and Naming Problems 15.2. Polymer Nanoparticles From Nanoemulsions 15.2.1. Polymers and Copolymers by Miniemulsion (Co)Polymerization 15.2.2. Surface-Functionalized Nanoparticles 15.2.3. Polymer Nanoparticles by Emulsion-Solvent Evaporation and by Ouzo Effect 15.2.4. Polymer Nanocapsules From Nanoemulsions 15.3. Inorganic Nanoparticles From Nanoemulsions 15.3.1. Nanodroplets as Templates for Inorganic Synthesis 15.3.2. Interfacial Precipitation and Crystallization in Nanoemulsions: Formation of Capsules 15.4. Polymer/Inorganic Hybrid Nanoparticles From Nanoemulsions 15.4.1. Encapsulation or Integration of Inorganic Components Within Polymer Particles Prepared in Nanoemulsions 15.4.1.1. Miniemulsion Polymerization 15.4.1.2. Emulsion-Solvent Evaporation 15.4.1.3. Pickering Nanoemulsions 15.4.1.4. Role of Functionalization in Structure Control 15.4.2. Polymer Nanoparticles Formed in Nanoemulsions as Templates for Inorganic Synthesis 15.4.3. Polymer/Inorganic Hybrid Capsules 15.5. Further Applications in Synthetic Processes of Nanoparticles Prepared in Nanoemulsions 15.6. Summary and Perspectives Acknowledgments References Part V: Characterization and Analysis of Nanoemulsions Chapter 16: Characterization of Particle Properties in Nanoemulsions 16.1. Introduction 16.2. Particle Size 16.2.1. Microscopy 16.2.2. Light Scattering 16.2.2.1. Static Light Scattering 16.2.2.2. Dynamic Light Scattering 16.2.3. Electric Pulse Counting 16.2.4. Sedimentation 16.2.5. Ultrasonic Spectrometry 16.2.6. Nuclear Magnetic Resonance 16.3. Particle Concentration 16.3.1. Proximate Analysis 16.3.2. Electrical Conductivity 16.3.3. Density Measurements 16.4. Particle Charge 16.4.1. Electroosmosis 16.4.2. Electrophoresis 16.4.3. Streaming Current 16.4.4. Sedimentation Potential 16.5. Particle Physical State 16.5.1. Thermal Analysis 16.5.1.1. Differential Scanning Calorimetry 16.5.1.2. Differential Thermal Analysis 16.5.1.3. Ultrasonic Spectrometry 16.5.1.4. X-Ray Diffraction 16.5.1.5. Dilatometry 16.5.1.6. Nuclear Magnetic Resonance 16.6. Interfacial Characteristics 16.7. Conclusions Acknowledgments References Chapter 17: Characterization of Physicochemical Properties of Nanoemulsions: Appearance, Stability, and Rheology 17.1. Introduction 17.2. Appearance 17.2.1. Optical Properties of Nanoemulsions 17.2.1.1. Transmission and Reflectance of Light 17.2.1.2. Absorption of Light 17.2.1.3. Scattering of Light 17.2.2. Quantitative Characterization of Appearance (Instrumental Analysis) 17.2.2.1. Spectrophotometric Colorimeters Transmission Spectrophotometry Reflectance Spectrophotometry 17.2.2.2. Trichromatic Colorimeters 17.2.2.3. Impact of Measurement Cells 17.2.2.4. Image Analysis of Color 17.2.3. Qualitative Characterization of Appearance (Sensory Analysis) 17.3. Stability 17.3.1. Gravitational Separation 17.3.1.1. Principles 17.3.1.2. Characterization 17.3.2. Droplet Aggregation 17.3.2.1. Principles 17.3.2.2. Characterization Flocculation Coalescence 17.3.3. Ostwald Ripening 17.3.3.1. Principles 17.3.3.2. Characterization 17.3.4. Chemical Destabilization 17.4. Rheology 17.4.1. Rheological Properties of Nanoemulsions 17.4.2. Measurement of Rheological Properties 17.4.2.1. Shear Rheology Measurements Small Deformation Large Deformation Experimental Errors 17.4.2.2. Advanced Measurement Methods 17.4.2.3. Empirical Measurement Methods 17.5. Conclusion References Chapter 18: Characterization of Gastrointestinal Fate of Nanoemulsions 18.1. Introduction 18.2. Overview of Gastrointestinal Fate of Nanoemulsions 18.2.1. Mouth 18.2.2. Stomach 18.2.3. Small Intestine 18.2.4. Colon 18.3. Changes in Nanoemulsion Properties During GIT Travel 18.3.1. Particle Composition and Structure 18.3.2. Particle Dimensions 18.3.3. Interfacial Properties 18.3.4. Physical State 18.4. In Vitro and In Vivo GIT Models for Nanoemulsions 18.4.1. Static In Vitro Gastrointestinal Model 18.4.2. Characterization of Changes in Nanoemulsion Properties in GIT 18.4.3. Bioaccessibility and Absorption of Nutrients and Bioactive Agents in GIT 18.4.4. Animal and Human Studies for GIT Fate of Nanoemulsions 18.4.4.1. In Vivo Approaches 18.4.4.2. In Vitro-In Vivo Correlations 18.5. Conclusions References Chapter 19: Safety of Nanoemulsions and Their Regulatory Status 19.1. Introduction 19.2. Safety of Nanoemulsions 19.2.1. Nanoemulsion Composition 19.2.2. Nanoemulsion Structure 19.2.3. Interaction of Nanoemulsions With the Biological Systems 19.2.4. Administration Route of Nanoemulsions 19.3. Regulatory Status of Nanoemulsions 19.3.1. Definitions and Current Status 19.3.2. Scientific Suggestions for Nano-Regulations 19.4. Conclusion and Perspectives Acknowledgments References Index Back Cover __Nanoemulsions: Formulation, Applications, and Characterization__ provides detailed information on the production, application and characterization of food nanoemulsion as presented by experts who share a wealth of experience. Those involved in the nutraceutical, pharmaceutical and cosmetic industries will find this a useful reference as it addresses findings related to different preparation and formulation methods of nanoemulsions and their application in different fields and products. As the last decade has seen a major shift from conventional emulsification processes towards nanoemulsions that both increase the efficiency and stability of emulsions and improve targeted drug and nutraceutical delivery, this book is a timely resource.