Podcast
Questions and Answers
What is the term for the transition that takes place in one direction only?
What is the term for the transition that takes place in one direction only?
How many polymorphic forms of cocoa butter are mentioned in the text?
How many polymorphic forms of cocoa butter are mentioned in the text?
What is the term for a substance that forms crystalline structures incorporating solvent molecules into the crystal lattice?
What is the term for a substance that forms crystalline structures incorporating solvent molecules into the crystal lattice?
Why do different solvates of the same drug produce different blood concentrations?
Why do different solvates of the same drug produce different blood concentrations?
Signup and view all the answers
Which form of cocoa butter is best suited for use as a suppository base?
Which form of cocoa butter is best suited for use as a suppository base?
Signup and view all the answers
What is the primary difference between solvates and polymorphs?
What is the primary difference between solvates and polymorphs?
Signup and view all the answers
What is a characteristic of polymorphism in crystalline solids?
What is a characteristic of polymorphism in crystalline solids?
Signup and view all the answers
What is a factor that influences the formation of polymorphs?
What is a factor that influences the formation of polymorphs?
Signup and view all the answers
Which of the following polymorphic forms has the highest energy state?
Which of the following polymorphic forms has the highest energy state?
Signup and view all the answers
What is enantiotropic transition?
What is enantiotropic transition?
Signup and view all the answers
What is the characteristic of a stable polymorph?
What is the characteristic of a stable polymorph?
Signup and view all the answers
What is an example of polymorphism in a natural substance?
What is an example of polymorphism in a natural substance?
Signup and view all the answers
What is the primary difference between hydrates and true polymorphs?
What is the primary difference between hydrates and true polymorphs?
Signup and view all the answers
What is the purpose of X-ray diffraction in pharmaceutical analysis?
What is the purpose of X-ray diffraction in pharmaceutical analysis?
Signup and view all the answers
What is the primary application of thermal analysis in pharmaceuticals?
What is the primary application of thermal analysis in pharmaceuticals?
Signup and view all the answers
What is the primary advantage of using TGA in pharmaceutical analysis?
What is the primary advantage of using TGA in pharmaceutical analysis?
Signup and view all the answers
What is the primary difference between amorphous and crystalline compounds in terms of X-ray diffraction?
What is the primary difference between amorphous and crystalline compounds in terms of X-ray diffraction?
Signup and view all the answers
What is the primary purpose of DSC and TGA in pharmaceutical analysis?
What is the primary purpose of DSC and TGA in pharmaceutical analysis?
Signup and view all the answers
Study Notes
Polymorphism
- Polymorphism is a property of crystalline solids, where molecules arrange or orient themselves in two or more different ways.
- Polymorphs have different physical properties, such as melting point, solubility, and X-ray diffraction.
- Formation of polymorphs depends on the conditions of crystallization, solvent used, rate of crystallization, impurities, supersaturation, and temperature.
Types of Polymorphic Transitions
- Monotropic transition: a transition that takes place in one direction only, for example, from a metastable to a stable form.
- Enantiotropic transition: a reversible change of the polymorphic forms from one to another.
Properties of Polymorphs
- Stable polymorph represents the lowest energy state and has the highest melting point and the least aqueous solubility.
- Metastable form represents the higher energy state and has a lower melting point and high aqueous solubility.
- Metastable form converts to the stable form due to their higher energy state.
Cocoa Butter
- Cocoa butter has 4 polymorphic forms: meta-stable gamma (18°C), alpha form (22°C), beta prime form (28°C), and stable beta form (34.5°C).
- The stable beta form is best suited for use as a suppository base.
Pseudo-Polymorphism
- Pseudo-polymorphism is caused by changes in the crystallization process, which results in the inclusion of solvent molecules in the crystal, producing solvates or hydrates.
- Solvates or hydrates differ in properties from the non-solvated sample, just like different polymorphic forms.
- Different solvates of the same drug can produce different blood concentrations from the administered solid oral dosage form.
Solvates and Hydrates
- Solvates: crystalline structures in which solvent molecules are incorporated into the crystal lattice, exhibiting different physical properties compared to the anhydrous form.
- Hydrates: crystalline forms of a substance in which water molecules are incorporated into the crystal lattice, affecting properties such as solubility and stability.
X-Ray Diffraction
- X-ray diffraction method is used to differentiate between solvates and true polymorphs by changing the temperature.
- Amorphous compounds have no definite peak in X-ray spectra.
Thermal Analysis
- Thermal analysis methods are used to characterize the physical and chemical changes of materials upon heating or cooling.
- Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) are commonly used methods.
- Thermal analysis is important for the determination of purity, polymorphism, moisture content, amorphous content, and stability.
TGA (Thermogravimetric Analysis)
- TGA is used to measure residual solvents and moisture, and can also be used to determine solubility of pharmaceutical materials in solvents.
- Analysis of pharmaceutical materials is a large area of application for thermal analysis.
- Three types of thermogravimetry are used.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
This quiz covers the physicochemical characteristics of drugs, focusing on polymorphism in crystalline solids. Learn about the different physical properties of polymorphs, including melting point, solubility, and X-ray diffraction. Test your knowledge on the formation of polymorphs and their conditions.