Nernst-Brunner model

With very few exceptions, dissolution of the drug substance in the GI tract milieu is a prerequisite for drug absorption following oral administration. For Class II compounds, the rate-limiting factor in their intestinal absorption is dissolution /solubility [23-25]. Hence, in-depth understanding of this process is essential in the oral delivery of low-solubility compounds. Factors governing the dissolution process can be directly identified from the following equation, based on the Nernst-Brunner and Levich modifications of the Noyes-Whitney model [26-28] ... 

Figure 5.2 Model of stationary diffusion in a stirred electrolyte. The Nernst-Brunner diffusion layer forms on an electrode surface of thickness because the viscosity of the electrolyte creates a gradient of convection between the bulk electrolyte and the electrode surface.

The studies in Ref 22 and 29 presented an analytical method for modeling the dissolution kinetics under the transient condition. The dissolution rate may be modeled with the Nernst-Brunner relationship (Ref 30), which gives the following time dependence of substrate metal concentration in a solder system ... 

A more general theoretical approach for dissolution modeling called the Film-Model Theory was postulated by Nernst (1904) and expanded upon by Brunner (1904) in an effort to deconvo-lute the components of the dissolution constinIBoth Nernst and Brunner made the following assumptions ... 

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