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Questions and Answers
What defines a crystalline solid?
What does Boyle’s Gas Law describe?
Why are polymorphs important in pharmaceuticals?
What is the definition of a pharmaceutical salt?
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What is the relationship between particle size and dissolution rate?
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What issue is associated with the anhydrous form of chloramphenicol palmitate?
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What is the angle of repose related to in pharmaceutics?
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What is defined as the heat required to convert a solid into a liquid?
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Which of the following is NOT an example of micromeritics properties?
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What happens to kinetic energy as temperature increases?
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What is the USP classification of particle size for 'very coarse' particles?
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What microscopy technique is primarily used for analyzing nanoparticles?
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How is porosity expressed in powders?
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What does the term 'bulkiness' refer to in the context of powders?
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What is the key difference between true density and bulk density?
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What does wettability measure with respect to a powder surface?
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What does 'true volume' of a powder refer to?
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What is the angle of repose formula used to calculate?
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How does smaller particle size influence powder flow?
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What is a potential solution for wetting problems in pharmaceutical formulations?
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Study Notes
States of Matter
- Solids, liquids, and gases are the three states of matter.
- Kinetic energy increases with temperature (KE ∝ T).
- Single covalent bonds typically have an energy of ~330 kJ/mol.
Boyle’s Gas Law
- Boyle’s gas law states that pressure is inversely proportional to volume (PV = constant) at a constant temperature.
Pharmaceutical Aerosols
- Pharmaceutical aerosols utilize phase transitions between gas and liquid.
- They contain a liquefied gas as a dispersion medium or propellant.
Crystalline Solids
- Crystalline solids have molecules arranged in a regularly ordered, repeating pattern.
- Different crystalline forms of the same substance are called polymorphs.
- Polymorphs can affect a drug's solubility, dissolution rate, bioavailability, and stability.
Amorphous Solids
- Amorphous solids lack a regular arrangement of molecules.
Pharmaceutical Salts
- Pharmaceutical salts are crystalline salts formed by combining an acidic or basic drug with a counterion.
- They are used for improved bioavailability, developability, purification, and patent advantages.
Cocrystals
- Cocrystals are crystalline complexes of two or more neutral molecules that are solid at ambient conditions.
Heat of Fusion
- The heat required to convert a solid into a liquid by increasing intermolecular distances is called the heat of fusion.
Powder Properties
- A powder is a dry substance composed of finely divided particles.
- The science of small particles is called micromeritics.
- Micromeritic properties include:
- Particle size
- Size distribution
- Shape
- Angle of repose
- Porosity
- Bulk density
Particle Size
- Particle size affects pharmaceutical formulations by influencing:
- Mixing
- Blending
- Dose uniformity
- Powder flow
- Dissolution
- Suspendability
- Smaller particles dissolve faster than larger particles.
- Particle size can be measured using ensemble methods (e.g., sieving, light scattering) and number counting methods (e.g., microscopy).
USP Classification
- The USP classifies particle size for "very coarse" particles as those that pass through a #8 sieve (2,360 µm).
Microscopy Techniques
- Transmission Electron Microscopy (TEM) is used for analyzing nanoparticles.
Porosity
- Porosity is the ratio of void space to the bulk volume, expressed as a percentage.
Bulkiness
- Bulkiness is the reciprocal of the apparent density, expressed in mL/g.
- Bulkiness is measured by the volume of the powder divided by the weight.
Density
- True density refers to the density of the particles themselves, while bulk density includes the voids between particles.
Porosity Formula
- The formula for porosity is: Porosity = (V_bulk – V_true) / V_bulk × 100.
Wettability
- Contact angle is a measure of a powder surface's wettability by a liquid.
- Young’s equation relates surface free energy to the contact angle of a liquid on a solid.
- Wettability is important for ensuring the proper dispersion of powders in liquids and penetration of liquid into tablets.
- Surfactants can be added to formulations to address wetting problems.
Volumes
- True volume refers to the volume occupied by the powder particles themselves, excluding voids.
- Bulk volume is the total volume occupied by a powder, including the void spaces.
Void in Micromeritics
- Void is the ratio of the space (void) to the volume of the powder.
Equivalent Sphere Diameter
- The equivalent sphere diameter is used to describe the size of irregular particles based on volume, surface area, or mass.
Powder Flow
- Smaller particles tend to have worse flow properties.
Angle of Repose Formula
- The angle of repose formula is: tan θ = h / r, where h is the height of the powder cone and r is the radius.
Particle Size and Aerosolization
- Smaller particles are more effective for dry powder inhalers.
Magnesium Carbonate
- True volume of magnesium carbonate powder measures the actual space occupied by the particles, calculated using true density and mass.
- Bulk density of magnesium carbonate powder is the weight of the sample divided by the bulk volume.
- Bulkiness is calculated by the bulk volume divided by the weight of the sample.
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Description
Explore the fundamental concepts of states of matter, including solids, liquids, and gases. This quiz covers important laws, such as Boyle’s gas law, and delves into the characteristics of crystalline and amorphous solids, as well as pharmaceutical applications. Test your knowledge on how these principles apply to real-world situations.