| Technique | What Property Does It Measure? | What Is The Information Used For? |
Physicochemical Properties | Inverse Gas Chromatography (iGC) | Surface energy | • Determination of surface interactions within formulations • Studying effects of processing techniques e.g. blending, milling • Assessing manufacturability, processability, aging, dissolution kinetics • Studying drug-carrier interactions • Optimization of formulation design |
Dynamic Vapor Sorption (DVS) | Solvent interaction, hygroscopicity | • Formulation and packaging design • Determining manufacture conditions • Determining storage and transportation conditions • Studying stoichiometry |
Fourier Transform Infrared (FT-IR) Spectroscopy | Chemical structure and identity | • Material identity confirmation • Molecular structure and functional group determination • Drug-excipient interaction determination • Identification of impurities or contamination |
Others | Viscosity, pH, Karl Fisher | Flowability, homogeneity, stability, solubility, dissolution rate, moisture content |
Size & Shape | Light Microscopy | Particle size, shape and morphology | • Choosing optimal parameters for other techniques, e.g. laser diffraction • Identifying particle behavior (e.g. agglomeration), and defects (e.g. contamination) • Determining birefringence, crystallinity |
Scanning Electron Microscopy (SEM) | Particle size, shape, morphology, behavior and interactions | • Nano- and micro-scale size and shape assessment • Visualization of agglomeration and defects • Identification of interactions between drug substance and excipients • Choosing optimal parameters for other techniques, e.g. laser diffraction • Studying the distribution of elements within drug particles (when combined with Energy Dispersive X-ray (EDX) spectroscopy) • Identification of defects e.g. contamination |
Laser Diffraction | Particle size distribution (PSD) | • Studying the effects of processing e.g. milling • Developing new materials and products with desired PSD for optimal bioavailability, dissolution, absorption • Optimizing manufacturing process |
Dynamic Image Analysis (QICPIC) | Particle size and shape | • Better description of size and shape of non-spherical particles • Identification of unusual particles, e.g. contamination, fibers • Ensuring quality and batch consistency |
Light Obscuration (HIAC) | Particle size | • Performing visible and sub-visible particulate matter testing |
Surface | Gas Adsorption Analysis | Specific surface area and porosity | • Understanding dissolution rate, processing, useful shelf-life and bioavailability • Stability of the API / excipient • Selection of appropriate formulation and processing methods • Optimization of drug release rate and targeting |
Density | Gas pycnometry | True density and volume | • Ensuring quality and consistency of materials • Supporting other characterization such as gas adsorption and modelling |
Bulk & Tap Density | Density, packing properties | • Determine flowability, compressibility, compactability • Determine packing and filling properties of materials |
Solid Form Characterization | Powder X-ray Diffraction (PXRD) | Crystallinity, crystal structure, polymorphism, amorphous content, purity, phase identity | • Phase identification and purity • Quantitative phase analysis • Polymorphism screening and identification of optimal crystalline form • Determination of crystallinity and amorphous content • Determination of batch consistency • Identification of contaminants • Amorphous characterization |
Differential Scanning Calorimetry (DSC) | Solvates, Hydrates, Glass Transition, Melting Point, Thermal Stability | • Determining compatibility and interactions between formulation components • Assessing purity • Amorphous content determination • Glass transition point determination • Support polymorph screening |
Thermogravimetric Analysis (TGA) | Thermal stability, volatiles content (e.g. moisture, solvent), purity | • Determining hydration / solvation levels • Determining degradation pathways • Developing and optimizing manufacturing processes • Designing packaging and storage conditions |
Hot Stage Microscopy | Melting/boiling point, thermal stability, desolvation, phase transitions, miscibility | • Supporting formulation development • Visualizing crystallization process, desolvation, polymorphism, phase transitions, melting/boiling points, glass transitions • Troubleshooting problems • Supplementing DSC and TGA data • Supporting thermal analysis method development • Cocrystal screening |
Fourier Transform Infrared (FT-IR) Spectroscopy | Chemical structure and identity | • Material identity confirmation • Molecular structure and functional group determination • Drug-excipient interaction determination • Identification of impurities and contamination |