PROPERTY OF SOLIDS (PART 1) PDF

PROPERTY OF SOLIDS (PART 1) – DR. YANG 1. What are the three states of matter? A : Solid, liquid, and gas. 2. What is the energy of a typical single covalent bond? A : ~330 kJ/mol. 3. What happens to kinetic energy as temperature increases? A : Kinetic energy increases (KE ∝ T). 4. What is Bo...

PROPERTY OF SOLIDS (PART 1) – DR. YANG 1. What are the three states of matter? A : Solid, liquid, and gas. 2. What is the energy of a typical single covalent bond? A : ~330 kJ/mol. 3. What happens to kinetic energy as temperature increases? A : Kinetic energy increases (KE ∝ T). 4. What is Boyle’s Gas Law? A : Pressure is inversely proportional to volume (PV = constant) at constant temperature. 5. What is the role of pharmaceutical aerosols? A : They contain a liquefied gas as a dispersion medium or propellant, utilizing phase transitions between gas and liquid. 6. What is a crystalline solid? A : A solid where molecules are packed in a regularly ordered, repeating pattern. 7. What is an amorphous solid? A : A solid where molecules are not arranged in a regular pattern. 8. What are polymorphs? A : Different crystalline forms of the same chemical substance. 9. Why are polymorphs important in pharmaceuticals? A : They affect properties like solubility, dissolution rate, bioavailability, and stability. 10. What is the issue with chloramphenicol palmitate’s anhydrous form? A : It is not bioavailable. 11. What solid-state form of enalapril maleate is toxic? A : Form I produces a toxic degradation product. 12. What is a pharmaceutical salt? A : A crystalline salt formed by combining an acidic or basic drug with a counterion. 13. Why are salts used in pharmaceuticals? A : For improved bioavailability, developability, purification, and patent advantages. 14. What are cocrystals? A : Crystalline complexes of two or more neutral molecules that are solid at ambient conditions. 15. What is the heat of fusion? A : The heat required to convert a solid into a liquid by increasing intermolecular distances. 16. What is the definition of a powder in pharmaceutics? A : A dry substance composed of finely divided particles. 17. What is micromeritics? A : The science of small particles. 18. What are some micromeritic properties? A : Particle size, size distribution, shape, angle of repose, porosity, and bulk density. 19. How does particle size affect pharmaceutical formulations? A : It influences mixing, blending, dose uniformity, powder flow, dissolution, and suspendability. 20. What is the angle of repose? A : It is the angle formed when a powder is allowed to fall freely, used to estimate flow properties. 21. What is the relationship between particle size and dissolution rate? A : Smaller particles dissolve faster. 22. What are the two main methods of particle size measurement? A : Ensemble methods (e.g., sieving, light scattering) and number counting methods (e.g., microscopy). 23. What is the USP classification of particle size for "very coarse" particles? A : Particles pass through a #8 sieve (2,360 µm). 24. What microscopy technique is used for nanoparticles? A : Transmission Electron Microscopy (TEM). 25. How is porosity defined in powders? A : Porosity is the ratio of void space to the bulk volume, expressed as a percentage. 26. What is bulkiness in powders? A : Bulkiness is the reciprocal of the apparent density, expressed in mL/g. 27. How is true density different from bulk density? A : True density refers to the density of the particles themselves, while bulk density includes the voids between particles. 28. What is the formula for porosity? A : Porosity = (V_bulk – V_true) / V_bulk × 100. 29. What is the contact angle a measure of? A : Wettability of a powder surface by a liquid. 30. How does the Young’s equation relate to wettability? A : It relates surface free energy to the contact angle of a liquid on a solid. 31. Why is good wetting important in pharmaceutical formulations? A : It ensures proper dispersion of powders in liquids and penetration of liquid into tablets. 32. How can wetting problems be solved in pharmaceutical formulations? A : By including surfactants in the formulation. 33. What does "true volume" refer to in powders? A : The volume occupied by the powder particles themselves, excluding voids. 34. What is "bulk volume" in powders? A : The total volume occupied by a powder, including the void spaces. 35. What is void in micromeritics? A : The ratio of the space (void) to the volume of the powder. 36. What is the significance of equivalent sphere diameter in particle size? A : It is used to describe the size of irregular particles based on volume, surface area, or mass. 37. How does particle size affect powder flow? A : Smaller particles tend to have worse flow properties. 38. What is the angle of repose formula? A : tan θ = h / r, where h is the height of the powder cone and r is the radius. 39. What is the relevance of particle size in aerosolization? A : Smaller particles are more effective for dry powder inhalers. 40. What does "true volume" of magnesium carbonate powder measure? A : The actual space occupied by the particles, calculated using true density and mass. 41. What is the bulk density of magnesium carbonate powder? A : Bulk density is the weight of the sample divided by the bulk volume. 42. How is bulkiness calculated? A : Bulkiness = 1 / apparent density. 43. What is the bulkiness of magnesium carbonate powder with a bulk density of 0.07 g/mL? A : 14.28 mL/g. 44. What is an example of a fine particle size classification in the USP? A : All particles pass through a #60 sieve (250 µm), with not more than 40% passing through a #100 sieve. 45. What microscopy method is used for particles larger than 1 µm? A : Optical Microscopy. 46. How does particle size influence dose uniformity in formulations? A : Smaller particles allow for more uniform doses. 47. What happens to powder flow when particle size decreases? A : Powder flow becomes worse. 48. How does wettability affect the dispersion of powders in liquids? A : Good wettability ensures better dispersion. 49. What forces influence the contact angle of a liquid droplet on a solid? A : The surface tension of the solid, the solid-liquid interfacial tension, and the liquid's surface tension. 50. What is the pharmaceutical implication of surface free energy in powder adhesion? A : Surface free energy affects the mechanical properties of tablets and the adhesion of powders.