Simultaneous determination of zidovudine and lamivudine from rat plasma, amniotic fluid and tissues by HPLC

A sensitive HPLC method has been developed and validated for the simultaneous quantification of zidovudine (AZT) and lamivudine (3TC) in rat plasma, amniotic fluid and placental and fetal tissues. Samples were processed by solid-phase extraction using C2 cartridges. Chromatography was performed using a phenyl column (5 microm, 150 x 2 mm i.d.) under a flow rate of 0.2 mL/min. The mobile phase consisted of 8% acetonitrile in 5 mM 1-heptane sulfonic acid dissolved in 30 mM ammonium formate buffer (pH 3.3). The method was validated in the range 0.25-50 microg/mL for both 3TC and AZT in the four biological matrices. Finally, the method was applied to a study involving fetal transport of co-administration of these compounds in a pregnant rat.