Colloid formation by drugs in simulated intestinal fluid.
Many organic molecules form colloidal aggregates in aqueous solution at micromolar concentrations. These aggregates promiscuously inhibit soluble proteins and are a major source of false positives in high-throughput screening. Several drugs also form colloidal aggregates, and there has been speculation that this may affect the absorption and distribution of at least one drug in vivo. Here we investigate the ability of drugs to form aggregates in simulated intestinal fluid. Thirty-three Biopharmaceutics Classification System (BCS) class II and class IV drugs, spanning multiple pharmacological activities, were tested for promiscuous aggregation in biochemical buffers. The 22 that behaved as aggregators were then tested for colloid formation in simulated intestinal fluid, a buffer mimicking conditions in the small intestine. Six formed colloids at concentrations equal to or lower than the concentrations reached in the gut, suggesting that aggregation may have an effect on the absorption and distribution of these drugs, and potentially others, in vivo.
Doak
Allison K
AK
Department of Pharmaceutical Chemistry, University of California-San Francisco, San Francisco, California 94158-2550, USA.
Wille
Holger
H
Prusiner
Stanley B
SB
Shoichet
Brian K
BK
D002021:Buffers; D011232:Chemical Precipitation; D003102:Colloids; D007421:Intestine, Small; D008027:Light; D046529:Microscopy, Electron, Transmission; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D012542:Scattering, Radiation; D012995:Solubility
D002021:Buffers; D003102:Colloids; D004364:Pharmaceutical Preparations