[Amputation and prosthesis attachment of the lower extremities].

Approximately 61,000 amputations are performed in Germany per year. In most cases the lower limbs are affected. The reasons for amputations are arteriosclerosis, diabetes mellitus, severe infections, tumors and complex trauma to the extremities.

[Mucus models for investigation of intestinal absorption mechanisms. 4. Comparison of mucus models with absorption models in vivo and in situ for prediction of intestinal drug absorption].

Intestinal absorption with an in vitro model using pig intestinal mucus was examined by means of in vivo and in situ experiments in the rat. With 10 compounds of different structure, in vitro, in situ, and in vivo models were tested. The in vitro model in the present form can only simulate the first step of intestinal absorption, namely diffusion through the mucus layer.

[Mucus models for investigation of intestinal absorption mechanisms. 3. A mathematical simulation model of drug diffusion through enteral mucus].

The diffusion of drug substance in a closed three-compartment model through a mucus layer to equilibrium is simulated by available pharmacokinetic programs. The obtained curves conform very well to the values experimentally found. If mucus is replaced by buffer solution an explicit equation from the literature, the method used and the experimental findings give the same results.

[Mucus models for investigation of intestinal absorption mechanisms. 2. Mechanisms of drug interactions with intestinal mucus].

Using in vitro models previously described [1] mucus retention and mucus diffusion of polar and non-polar drugs were measured. It could be shown that drug interaction with pig intestinal mucus was based on non-specific binding. The pH-dependence of retention by mucus does not confirm electrostatic interaction of drugs with mucus but favour drug distribution to hydrophobic areas within the mucus.