For the non-ionizable compounds, different plasma concentration curves were obtained when ethanol was included as compared to the fasted state. The absorption of griseofulvin and progesterone was slightly increased
with around 15% higher values for the Fabs, Cmax, and AUC for both compounds. The moderate increase in absorption of griseofulvin is surprising because this compound has been shown to exhibit strong food effects ( Ogunbona et al., 1985). Furthermore it is only slightly solubilized by lipid aggregates ( Persson et al., 2005) compared to the effect ethanol has on its Sapp in gastric and intestinal media ( Fagerberg et al., 2012). One explanation for this is that the mixed lipid aggregates are present much longer in the intestinal fluid compared to the transiently elevated GS-1101 price levels of the rapidly absorbed ethanol. The increased absorption of both progesterone and griseofulvin is also absent when ethanol is only present in the gastric compartment. Felodipine however, which is strongly affected by ethanol in both gastric and intestinal simulated media, maintained the increased absorption when ethanol was
only present in the gastric compartment. There are two possible explanations for this result. First, the drug is effectively solubilized by the mixed lipid aggregates found in FaSSIF that help maintain the Etoposide high amount of dissolved substance during the gastrointestinal transit time. Second, the
equilibrium between the substance in solution and that solubilized in aggregates is rapid, which helps to push permeation through the gut wall. Ethanol has previously been shown to increase the absorption or at least plasma concentration of drugs taken concomitantly with it. In humans, the plasma concentration of diazepam almost doubles due to enhanced absorption in the presence of even a small amount of hard liquor (Hayes et al., 1977). Although this is a soluble BCS class I compound, it is lipophilic and neutral in intestinal media and may thus potentially dissolve quicker and be absorbed faster in the presence of alcohol with a higher plasma concentration peak as a result. The effects of ethanol on ADP ribosylation factor the in vivo absorption of acetylsalicylic acid (a soluble weak acid with pKa of ∼3.5 and low permeability) are ambiguous and range from negative ( Melander et al., 1995) to absent ( Hollander et al., 1981) in humans and even positive ( Kato et al., 2010) in mice. A very high dose were given to the mice (0.5 g/kg) making the cosolvent effect of ethanol on acetylsalicylic acid solubility ( Roberts et al., 2007) a possible reason for the enhanced absorption. The now withdrawn drug propoxyphene also obtained increased bioavailability when administered with ethanol in both humans ( Girre et al., 1991) and dogs ( Olsen et al.