11 Questions
How does the surface area of a drug particle change as the particle size decreases?
The surface area increases
Which equation is used to estimate the decrease in particle size required to increase in solubility?
Log (S/S0) = [2γ V/2.303 + RTr ]
What does the Noyes Whitney equation dC/dt = KS(CS-CF) represent?
Rate of dissolution
According to the Noyes Whitney equation, what happens if there is an increase in the total surface area of drug in contact with gastrointestinal fluid (GIF)?
Increase in dissolution rate
What is the main effect of increasing the surface area exhibited by a drug particle?
Increase in solubility
Which parameter is important for drug absorption, dissolution, solubility, and bioavailability?
Surface area
What is the main factor affecting actual solubility of a drug particle when exposed to a medium?
Particle size
What does the term 'Log (S/S0)' represent in the context of drug particle size and solubility?
Solubility ratio between small and large particles
What does the term 'Y' represent in the equation Log (S/S0) = [2γ V/2.303 + RTr ]?
Surface tension
What does the term 'R' represent in the equation Log (S/S0) = [2γ V/2.303 + RTr ]?
Gas volume
What does the term 'r' represent in the equation Log (S/S0) = [2γ V/2.303 + RTr ]?
Radius of small particle
Study Notes
- The properties of a drug that can be affected by particle size and particle size distribution include surface area, density, porosity and compressibility, angle of repose and flow property, bulkiness and packaging criteria, hygroscopicity, and electrostatic charge.
- Surface area is crucial for drug absorption, dissolution, solubility, and bioavailability.
- As the particle size decreases, the surface area of the particle increases, which can affect the actual solubility of the drug.
- The equation Log (S/S0) = [2γ V/2.303 + RTr ] can be used to estimate the decrease in particle size required to increase solubility.
- According to the Noyes-Whitney equation, an increase in the total surface area of the drug in contact with a dissolution medium will result in an increase in the dissolution rate due to the particles initially wetted by the medium.
- The effective surface area exhibited by the drug is directly proportional to the particle size.
- The dissolution rate constant, K, is a key factor in the Noyes-Whitney equation, which determines the rate at which the drug dissolves.
- The surface tension, molar volume, gas volume, absolute temperature, and radius of the small particle are also factors in the equation.
- The surface area is essential for drug dissolution because it increases the contact between the drug and the dissolution medium.
- The angle of repose and flow property, bulkiness, and packaging criteria are other related properties that can be influenced by particle size.
- Hygroscopicity refers to the ability of a substance to absorb moisture from the environment, while electrostatic charge relates to the presence of static electricity on the particle surface.
Explore the influence of particle size on pharmaceutical properties such as surface area, density, porosity, compressibility, and more. Understand how particle size affects drug absorption, dissolution, solubility, and bioavailability.
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