In Vivo Precipitation of Poorly Soluble Drugs from Lipid-Based Drug Delivery Systems

摘要

Precipitation of poorly water-soluble drugs from, lipid-based drug delivery systems (LbDDS) has been studied extensively during in vitro lipolysis but has never been shown in vivo. The aim of this study was therefore to investigate if drug precipitation can occur from LbDDS during transit of the gastrointestinal tract in vivo. Rats were administered 300 mu L of either of two LbIDDS (LbDDS I and LbDDS II) loaded with danazol or fenofibrate (or paracetamol to assess gastric emptying). The rats were euthanized at various time points after administration of both LbDDS Extensive drug No drug containing either drug, and the contents of the stomach and precipitation precipitation proximal part of the small intestine were harvested. The contents were analyzed for crystalline drug by X-ray powder diffraction and polarized light microscopy. No drug precipitation evident in the stomach or the intestine after administration of LbDDS I containing danazol at the tested time-points. Fenofibrate precipitation was absent in the stomach after administration of LbDDS I, but was evident in the stomach 90 min after dosing. No crystalline fenofibrate was observettin the intestine. Danazol and fenofibrate precipitation was evident in the stomach following administration of LbDDS II containing either drug, but not in the intestine at the tested time point. Drug precipitation from LbDDS was observed in the stomach, but not in the intestine, which is contrary to what in vitro lipolysis data (obtained under human GI conditions) suggests. Thus, precipitation of drugs from LbDDS in vivo in rats is much lower than might be anticipated from in vitro lipolysis data.