Nanoparticle structure development in the gastro‐intestinal model fluid FaSSIFₘₒd₆.₅ from several phospholipids at various water content relevant for oral drug administration

The characteristics of intestinal model fluids were investigated at conditions, which simulate the passage from the middle to the end of the duodenum. The formation and decay of liposomes and micelles in model bile fluids were studied, because of their role as an intermediate host for the resolution and uptake of hydrophobic drugs (BCS classes II, IV). The conditions, which may influence the formation of these nanoparticulate intermediates were studied, i.e., the lipid composition of the bile, the preparation method, the time of the passage through the modelled duodenum segment and the concentration, which results from the variable dilution of the bile by mixing with the transfer medium representing the fluid arriving from the stomach. The variation of the lecithin entity revealed an equivalence of Egg–lecithin of a high purity (99%) with its main component 1‐palmitoyl‐2‐oleoyl‐sn‐glycero‐3‐phosphocholine POPC, while 1,2‐di‐oleoyl‐sn‐glycero‐3‐phosphocholine DOPC resulted in a slight delay of the micelle‐liposome conversion. The FeSSIF preparation method was best with the sequential‐film method, while the bile‐film method yielded comparable results; the shake method showed a slightly different kinetics of the nanoparticle conversion. The time and concentration dependence of the formation and decay of lipidic nanoparticles indicates that these strongly depend on the passage time (speed) and bile dilution rate. The corresponding physiological conditions at healthy persons may vary in vivo individually and due to diseases. The studied conditions cover typical physiological conditions, which should be taken into consideration in the exploration of in vitro tests of formulations of hydrophobic drugs. Formation and decay of liposomes and micelles from bile in the duodenum was studied, due to their role as an intermediate for resolution and uptake of hydrophobic drugs (BCS II, IV). The physiological conditions studied may vary individually and due to diseases.