Sex-related differences in drug pharmacokinetics, especially regarding absorption and metabolism, are in part caused by a differential expression and/or activity of membrane transporters between males and females (Soldin and Mattison, 2009, Morris et al., 2013). Certain transporters are known to be influenced by formerly considered “inert” pharmaceutical excipients with which drugs are co-formulated. Indeed, excipients have shown a sex-specific influence on drug bioavailability via their interaction with transporters. A study on the influence of polyethylene glycol 400 (PEG 400) on the bioavailability of ranitidine in men and women showed that PEG 400 increased ranitidine absorption in men but not in women (Ashiru et al., 2008).

More