2.5 Drug parameters
Raltegravir (RAL) was included in this study as a probe substrate for the activity of UGT1A1 in pregnancy. RAL is solely metabolised by UGT1A1 and can be used to validate the ontogeny pf UGT1A1 in both pregnant and non-pregnant populations. Similarly, clinical PK data of RAL in both populations are available. Unlike CAB, clinical PK data for oral RPV in pregnancy are available [20, 21, 41]. However, there are no available PK data for LAI RPV in pregnancy. Physicochemical properties and in vitro data for the drugs modelled in this study (RPV, RAL and CAB) are listed in Table 1. Renal drug clearance was not implemented in the model as all three drugs are mainly cleared by the liver.