Poor Wetting and Solubility of Powders in Pharmacology

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What does the melting point of a crystalline solid indicate?

The density of the solid material

The strength of interactions between molecules in a solid (correct)

The external pressure applied to the solid

The color of the solid material

How does the heat of fusion relate to the strength of intermolecular forces?

Strong forces result in high heat of fusion and high melting point (correct)

Strong forces result in low heat of fusion and low melting point

Weak forces result in high heat of fusion and high melting point

Weak forces result in low heat of fusion and low melting point

How does the energy requirement for disrupting interactions within a solid relate to its melting point?

Higher melting point requires less energy

Lower melting point requires less energy (correct)

Higher melting point requires more energy

Lower melting point requires more energy

Why do polymorphic forms have different melting points?

Because they have different molecular forces Signup and view all the answers

What is the heat of fusion?

The energy required to bring about a state change from solid to liquid Signup and view all the answers

How does a crystal bound by weak forces differ from one bound by strong forces?

It has lower heat of fusion and low melting point Signup and view all the answers

What is the process in which a substance forms a solution called?

Dissolution Signup and view all the answers

What property is crucial for a drug to be absorbed at the site of absorption?

Solubility in the fluid Signup and view all the answers

What does the dissolution rate constant 'k' represent in the Noyes-Whitney equation?

Characteristics of each solid drug compound Signup and view all the answers

Which equation defines the rate of solution of solids?

Noyes-Whitney equation Signup and view all the answers

What determines the surface area 'A' of the dissolving solid in the Noyes-Whitney equation?

Particle size Signup and view all the answers

What is crucial for dissolved drug molecules to pass throughout the dissolving fluid to be absorbed?

Contact with absorbing mucosa Signup and view all the answers

What does a contact angle greater than 90° suggest?

Problems are likely during dispersion Signup and view all the answers

How is wettability of powders measured?

By the contact angle of the substance with water Signup and view all the answers

In terms of wetting tendency, what does a smaller contact angle indicate?

Larger wetting tendency Signup and view all the answers

What is solubility defined as?

The amount of drug dissolved in a given volume of a solvent Signup and view all the answers

What enhances solubility of a drug?

Decreased particle size Signup and view all the answers

Why are wetting agents (surfactants) included to improve wettability?

To help in dispersion of hydrophobic drugs Signup and view all the answers