Polymorphic Forms 29
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Questions and Answers

Which polymorphic form of testosterone has the highest melting point?

  • Form I (correct)
  • Form IV
  • Form II
  • Form III

    • What is the advantage of having metastable polymorphic forms in drug delivery?

  • They are more stable
  • They have lower melting points
  • They have better solubility (correct)
  • They have higher bioavailability

    • What differentiates crystal hydrates from anhydrates in terms of solubility?

  • Crystal hydrates are more soluble (correct)
  • Both have equal solubility
  • Solubility is not affected by hydration state
  • Anhydrates are more soluble

    • How do crystal hydrates and anhydrates of a drug differ in terms of stability?

    <p>Hydrates are less stable</p> Signup and view all the answers

    What type of crystal lattice defect can influence the physical properties of crystals by missing an atom?

    <p>Vacancy defect</p> Signup and view all the answers

    What knowledge is important for understanding crystal habit and polymorphism in the context of drug manufacturing?

    <p>Ability to differentiate between crystal hydrates and anhydrates</p> Signup and view all the answers

    What is one of the effects of different polymorphs on molecules?

    <p>Alter the thermodynamic stability</p> Signup and view all the answers

    Which physical property can be significantly impacted by polymorphism?

    <p>Melting point</p> Signup and view all the answers

    What type of transition involves a change from a metastable form to a stable form?

    <p>Monotropic transition</p> Signup and view all the answers

    How can polymorphism impact the manufacture of dosage forms?

    <p>By affecting dissolution rate</p> Signup and view all the answers

    Which form of a polymorph typically has the lowest free energy?

    <p>Stable form</p> Signup and view all the answers

    How does polymorphism influence the bioavailability of drugs?

    <p>By altering the drug's release rate</p> Signup and view all the answers

    How does the presence of surfactants in the crystallisation solution impact crystal habit modification?

    <p>Results in thin long needles</p> Signup and view all the answers

    What is the primary impact of polymorphism on a substance?

    <p>Alters the crystal lattice structure</p> Signup and view all the answers

    How do crystals with the same combinations of crystallographic forms but different crystal habits differ?

    <p>In their overall shapes</p> Signup and view all the answers

    What effect does anionic surfactants have on crystal habit?

    <p>Results in thin long needles</p> Signup and view all the answers

    How does polymorphism affect the physical properties of a substance?

    <p>It alters mechanical strength</p> Signup and view all the answers

    What is the role of impurities in modifying crystal habit?

    <p>Alters the crystal shape by adsorbing onto crystal faces</p> Signup and view all the answers

    What is the key difference between crystalline and amorphous materials based on the text?

    <p>Crystalline materials have a high degree of order in their arrangement of atoms and molecules, while amorphous materials have atoms and molecules arranged randomly.</p> Signup and view all the answers

    How does the text describe the crystallographic structure of crystals?

    <p>As a three-dimensional lattice with periodic reoccurrence of atoms and molecules in all three dimensions in space.</p> Signup and view all the answers

    What is the role of the unit cell in crystallography?

    <p>The unit cell is the repeating unit that forms the crystal lattice in crystalline materials.</p> Signup and view all the answers

    Which type of material shows a sharp transition from solid to liquid state upon heating?

    <p>Crystalline materials</p> Signup and view all the answers

    What are some examples of crystalline materials mentioned in the text?

    <p>Ibuprofen and sodium chloride</p> Signup and view all the answers

    How do amorphous substances differ from crystalline substances upon heating?

    <p>Amorphous substances experience a sharp transition from solid to liquid state, while crystalline substances soften.</p> Signup and view all the answers

    What are the three dimensions used to describe a unit cell?

    <p>a, b, c</p> Signup and view all the answers

    How many different basic crystal systems exist based on geometric descriptions?

    <p>Seven</p> Signup and view all the answers

    What term is used to describe the possibility of the presence of center atoms inside the unit cell or at edges of faces of the unit cell?

    <p>Bravais-lattices</p> Signup and view all the answers

    Which angles are used to describe a unit cell in crystallography?

    <p>α, β, γ</p> Signup and view all the answers

    How many degrees of order do the seven basic crystal systems cover for atoms and molecules?

    <p>All possible degrees</p> Signup and view all the answers

    What role does a unit cell play in determining crystallinity?

    <p>Geometric descriptor</p> Signup and view all the answers

    What term is used to describe crystal forms with different order of molecules or atoms but the same type of crystal lattice?

    <p>Polymorphic forms</p> Signup and view all the answers

    How can crystal habit be modified in the context of polymorphic forms?

    <p>Adding impurities, such as surfactants, to the crystallization solution</p> Signup and view all the answers

    What is the impact of anionic surfactants on crystal habit modification?

    <p>Thin long needle-like crystals</p> Signup and view all the answers

    What is the result of cationic surfactants on crystal habit modification?

    <p>Thin flaky plate-like crystals</p> Signup and view all the answers

    How do crystals with the same habit but different combinations of faces differ?

    <p>They may have different combinations of crystallographic forms</p> Signup and view all the answers

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