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Questions and Answers
What is a material, according to the text?
What is the significance of understanding the 'character' of a material for its application?
What are some common terms related to pharmaceutical materials mentioned in the text?
How are crystalline solids defined in the text?
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What property results from the long-range orderliness in crystalline solids?
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How many possible geometries for the unit cell are mentioned in the text?
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What is the purpose of Dynamic Vapour Sorption (DVS) in the pharmaceutical industry?
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Which technique is best suited for determining crystal structure in crystalline solids?
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What does Infrared Spectroscopy primarily identify within a molecular structure?
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What is a key indicator of the stability of colloidal dispersions?
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Which technique is used for measuring the change in sample mass as a function of temperature and/or time?
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Which parameter does Particle Size influence in pharmaceuticals?
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What characterizes Amorphous solids in thermal analysis techniques?
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Which technique is NOT commonly used for particle size measurements in the pharmaceutical industry?
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What is the main application of Vibrational Spectroscopy techniques such as Infrared Spectroscopy and Raman Spectroscopy in pharmaceutical analysis?
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What type of polymorphs does Nifedipine exhibit?
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Which type of solid has an ability to exist in two or more crystalline forms?
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Why is inattention to polymorphic forms of an Active Pharmaceutical Ingredient (API) considered harmful and expensive for pharmaceutical companies?
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Which pharmaceutical industry form usually exhibits a random molecular arrangement with a high degree of disorder?
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Why does the amorphous form of a drug usually have higher solubility than the crystalline form?
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Which technique would be most appropriate for evaluating the crystal form of a pharmaceutical substance?
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Which property is usually higher in the amorphous form compared to the crystalline form?
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Which type of polymer is formed from bi-functional and tri-functional monomers and contains strong covalent bonds between various linear polymer chains?
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What is the melting point of the most stable form of a certain polymer discovered in 1998?
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Which of the following is a semi-synthetic polymer?
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Which type of polymerisation reaction results in the elimination of small molecules such as water, alcohol, hydrogen chloride, etc.?
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Which natural polymer is a polyaminosaccharide derived from the N-deacetylation of chitin?
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Which type of polymer is known for its strong intramolecular H-bonding between hydroxyl and amino groups, making it thermo-stable?
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Which type of polymer is formed by linking together a large number of small molecules (monomers)?
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Which type of polymer is not classified based on its source?
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Which type of polymer is used for developing smart delivery systems?
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Which natural polymer is composed of glucose monomers joined in α 1,4 linkages and is typically derived from corn or potato?
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Study Notes
Temperature and Heat Flow
- Endothermic and exothermic processes occur in chemical reactions, involving heat absorption or release
- DSC (Differential Scanning Calorimetry) measures heat flow vs. temperature, providing information on melting points, crystallization, and phase transitions
DSC Applications
- Conversion of a monohydrated form of a drug compound to its anhydrous form
- Quantitative determination of the monohydrate and anhydrous forms in a mixture
- Calibration curve for quantitative determination of the monohydrate and anhydrous forms
Amorphous Solids
- Lack of a clear melt peak in DSC
- Presence of a Tg (glass transition temperature), indicating an endothermic process
- Amorphous solids have no long-range ordering of molecules, resulting in a high degree of disorder
Thermogravimetric Analysis (TGA)
- Measures the change in sample mass as a function of temperature and/or time
- Applications:
- Changes in mass due to decomposition, oxidation, evaporation, or combustion
- Absorbed moisture content
- Volatilization rate of materials
- Determination of processing or storage conditions
Dynamic Vapour Sorption (DVS)
- Interacts pharmaceutical solids with moisture, influencing material properties, processability, and stability
- Applications:
- Characterization of amorphous content
- Characterization of hydrate formation
- Characterization of glass transition and crystallization behavior
Vibrational Spectroscopy
- Infrared spectroscopy (IR) and Raman spectroscopy
- Fingerprinting identification of known scans
- Identifies functional groups within the molecular structure
- Determines protein secondary structure
- Identifies resins and opaque/coloured materials using photoacoustic scans
Polymorphs
- Nifedipine exists as three polymorphic forms: α, β, and γ
- Degree of polymorphism is produced by the degree of conformational rotations within the large flexible Nifedipine molecule
- IR spectra can show differences between polymorphic forms
Powder X-ray Diffraction (PXRD)
- An array of X-ray diffraction techniques exist for characterizing structural and chemical properties of crystalline solids
- Applications:
- Crystal structure determination
- Compound identification
- Determination of crystallographic orientation
- Particle size analysis
- Crystal strain measurement
- Degree of crystallinity/crystal quality
- Defect density and characterization
Particle Sizing
- Particle size influences physical and chemical properties
- Applications:
- Solubility
- Dissolution rate
- Bioavailability
- Common techniques for particle size measurements include:
- Sieving
- Microscopy (with or without image analysis)
- Electric stream sensing zone method (Coulter counter)
- Laser diffraction
- Sedimentation (by gravity or centrifugal)
- Ultrasonic attenuation
Particle Size and Zeta Potential
- Dynamic light scattering (DLS) measures particle size and zeta potential
- Applications:
- Analysing wet emulsion, suspension, and bulk dry dispersion
- Diverse sample types: abrasive, fragile, cohesive, or agglomerated
Other Analysis Techniques
- UV/VIS spectroscopy:
- Determines characteristic absorption patterns
- Used for qualitative detection, quantitative calculation, and kinetic analysis
- NMR spectroscopy:
- Solid-state characterization: crystal polymorphism, testing, and measuring polymorphic state
- Impurity analysis
- Mass spectrometry:
- Quantitative elemental analysis
- Molecular weight/formula evaluation
- Unknown purity evaluation
Polymorphism
- The ability of a solid to exist in two or more crystalline forms
- >50% of APIs in the pharmaceutical industry have polymorphs
- Chemically identical but with significant differences in physical properties (solubility, dissolution rate, Tm, hygroscopicity, etc.)
- Differences in bioavailability: low or high solubility
- Inattention to polymorphic forms of an API can be harmful and expensive for pharmaceutical companies
Multi-Tier Evaluation of API Candidates
- Tier 1: Crystallinity, optical microscopy, and powder X-ray diffraction (XRD)
- Tier 2: Thermal properties, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and dynamic vapour sorption (DVS)
- Tier 3: Polymorph and hydrate screening, XRD, Raman microscopy, and DSC
- Tier 4: Humidity/temperature-induced changes in crystal form, powder XRD, DSC, and DVS
Pharmaceutical Analysis
- Molecular level: Fourier Transform Infrared (FT-IR), Nuclear Magnetic Resonance (NMR) spectroscopy, and mass spectrometry
- Physical/Particulate/Morphology: thermal analyses, X-ray diffraction (XRD), and other techniques
- Quantitative: HPLC, UV/VIS spectroscopy, and other spectrophotometry methods
Solid Phase Transitions
- Knowledge of solid form transitions is important for pharmaceutical product preparation
- Processes may cause polymorph or amorphous form conversions
- Multi-tier evaluation of API candidates is necessary for thorough characterization
Polymer Classifications
- Based on source: natural, semi-synthetic, and synthetic polymers
- Based on structure: linear, branched, and cross-linked polymers
- Based on pharmaceutical applications: polymers in conventional dosage forms, controlled release dosage forms, and drug packaging
- Based on solubility: water-soluble and water-insoluble polymers
Polymer Properties
- Molecular weight
- Composition
- Mechanical/thermal properties
- Rheology
Pharmaceutical Applications of Polymers
- Natural polymers: starch, chitosan, and others
- Synthetic polymers: polythene, polyvinyl chloride, and others
- Applications: tablet and capsule diluents, disintegrants, glidants, binders, and others
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Description
This quiz covers the fundamentals of material science and its importance in the pharmaceutical industry, including the review of material science, solids and their properties, and pharmaceutical analysis. Topics include the application of materials in pharmaceuticals and understanding the characteristics required for specific applications.