Can the USP paddle method be used to represent in-vivo hydrodynamics?

Experiments in-vitro and in dogs were conducted to find in-vitro hydrodynamic conditions that can be used to represent gastrointestinal motility patterns. Specifically, the dissolution performance of micronised and coarse-grade felodipine (a poorly soluble, neutral, lipophilic drug) was studied in a biorelevant medium in the USP paddle apparatus at various paddle speeds. Ratios of percentage dissolved (slower:faster rev min(-1)) were calculated pairwise.

Influence of hydrodynamics and particle size on the absorption of felodipine in labradors.

Purpose: To study the influence of GI hydrodynamics and drug particle size on felodipine absorption in the dog.

Methods: Labradors fistulated at midjejunum were used to selectively study the influence of hydrodynamics and particle size on the in vivo dissolution and absorption of the poorly soluble, lipophilic drug felodipine. A combination of infusion and oral administration of either normal saline or a 5% glucose solution was used to maintain "fasted" and establish "fed" state motility patterns, respectively.