Noyes-Whitney equation and drug dissolution

The Noyes-Whitney equation was developed from careful observation of the dissolution behavior of solids in a solvent system (Fig. 8.3). The equation, in many aspects, is similar to Pick s law of diffusion (Ch. 5). 

The specific dissolution rate constant (iCi) is a constant for a specific set of conditions, although it is dependent on temperature, viscosity, agitation or stirring (which alters the thickness of diffusion layer) and volume of the solvent. 

The Noyes-Whitney equation tells us that the dissolution rate (dC/dt) of a drug in the GI tract 

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