What is Noyes and Whitney equation?

The Noyes-Whitney equation is a model that assumes that (1) the drug is dissolved uniformly from all surfaces of the particles, that (2) the particles are spherical, that (3) the thickness of the diffusion boundary layer is constantand that (4) the thickness of the diffusion boundary layer and the saturation solubility …

How do you use the Noyes-Whitney equation?

The dissolution rate of a solid in solvent is written by Noyes–Whitney equation, as follows,(1) dC dt = DS w Vh ( C s − C ) , where C and Cs represent the concentration of the dissolved substance at a given time t and the solubility concentration of the substance, respectively.

Does the Noyes-Whitney equation adequately predict the dissolution rates?

According to Noyes-Whitney equation when particle size is reduced, the total effective surface area is increased and thereby dissolution rate is enhanced. Additionally, reduction of particle size reduces the diffusion layer thickness surrounding the drug particles and thereby increases concentration gradient (4,50).

How do you calculate the rate of dissolving?

Dissolution rate can be expressed using the Noyes–Whitney equation. In this model, Cs is the saturation concentration of the solute in question in the given solvent.

What is Noyes Whitney law?

NOYES AND WHITNEY EQUATION The rate of change in concentration of dissolved material with time it directly proportional to the concentration difference between the two sides of diffusion layer i.e. = k (Cs- Cb) Where, dc/dt – Dissolution rate of drug.

Why is Noyes Whitney equation used?

The Noyes-Whitney function is used to represent how the solid material is dissolved into solution, and it is well used in study of drug dynamic.

How do you calculate drug release from dissolution?

Amount of drug released mg/ ml = Concentration × Dissolution bath volume × dilution factor/1000.

What is the relationship between solubility and dissolution rate?

Dissolution is a kinetic process, and is quantified by its rate. Solubility quantifies the dynamic equilibrium state achieved when the rate of dissolution equals the rate of precipitation.

What are 3 factors that affect the rate of dissolution?

The rate of dissolving depends on the surface area (solute in solid state), temperature and amount of stirring.

What is the difference between solubility and rate of dissolving?

Solubility is the amount of solute that can dissolve in a given amount of solvent at a given temperature. Temperature affects the solubility of solutes in all three states. Pressure also affects the solubility of gases. The rate of dissolving is the rate at which a solute dissolves in a solvent.

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