<qa>  What is the RAL?HIV-1 is shed in genital secretions which increase the risk of transmission between sexual partners and from mother to infant. Antiretroviral medication taken prior to exposure to HIV-1 can prevent viral transmission from a mother to her infant. Raltegravir RAL, by blocking integration of viral cDNA into the hosts genome, makes an excellent candidate for preventing HIV-1 infection. RAL is licensed for treatment with twice-daily dosing based on plasma trough concentrations; however, intracellular concentrations of RAL which are relevant to blocking infection of cells have not been previously studied. P-glycoprotein pumps, which are involved in regulating drug absorption and metabolism, can influence intracellular drug concentrations. P-glycoprotein concentrations appear to vary with menstrual cycle suggesting it may affect intracellular drug concentration of RAL in women. 