Determination of 3'-azido-2',3'-dideoxyuridine in maternal plasma, amniotic fluid, fetal and placental tissues by high-performance liquid chromatography

Antiretroviral bioanalysis methods of tissues and body biofluids

Research in the many areas of HIV treatment, eradication and prevention has necessitated measurement of antiretroviral (ARV) concentrations in nontraditional specimen types. To determine the knowledgebase of critical details for accurate bioanalysis, a review of the literature was performed and summarized. Bioanalytical assays for 31 ARVs, including metabolites, were identified in 205 publications measuring various tissues and biofluids. 18 and 30% of tissue or biofluid methods, respectively, analyzed more than one specimen type; 35-37% of the tissue or biofluid methods quantitated more than one ARV. 20 and 76% of tissue or biofluid methods, respectively, were used for the analysis of human specimens. HPLC methods with UV detection predominated, but chronologically MS detection began to surpass. 40% of the assays provided complete intra- and inter-assay validation data, but only 9% of publications provided any stability data with even less for the prevalent ARV in treatments.

Simultaneous determination of abacavir and zidovudine from rat tissues using HPLC with ultraviolet detection

A simple high-performance liquid chromatography (HPLC) method has been developed and validated for the simultaneous determination of abacavir and zidovudine (AZT) in rat plasma, amniotic fluid, fetal, and placental tissues. Extraction of abacavir, AZT, and the internal standard, azidouridine (AZDU) in amniotic fluid was carried out by protein precipitation. Extraction from plasma, fetal and placental homogenates was achieved by using a salting out technique. Chromatographic separation was performed using a C8 column (150 mm x 4.6 mm, 5 microm). The mobile phase consisted of 12% acetonitrile in 25 mM sodium phosphate buffer (adjusted to pH 7 with sodium hydroxide) for the fetus, placenta, plasma and amniotic fluid samples at a flow rate of 0.8 mL/min. The method was validated over the range from 0.05 to 50 microg/mL for both abacavir and AZT in the four biological matrices. The absolute recovery of abacavir ranged from 79 to 94%, while AZT recoveries ranged from 79 to 90% in the different biological matrices. The internal standard recovery ranged from 90 to 92%. Acceptable intra- and inter-day assay precision (<10% R.S.D.) and accuracy (<10% error) were observed over 0.05-50 microg/mL for all four matrices.

Determination of lamivudine in plasma, amniotic fluid, and rat tissues by liquid chromatography

An HPLC method for the quantification of lamivudine (3TC) in rat plasma, amniotic fluid, placental and fetal tissues has been developed, validated and applied to the study of the placental transport of this drug in the pregnant rat. Placental and fetal tissues were processed using liquid-liquid extraction enhanced by salting out the sample using a saturated solution of ammonium sulfate. Plasma and amniotic fluid samples were processed by protein precipitation using 2 M perchloric acid. Reverse phase chromatography was performed using a phenyl column (5 microm, 150 mm x 2 mm i.d.) under a flow rate of 0.2 ml/min. The mobile phase consisted of 5% methanol in 20 mM dibasic phosphate buffer (pH 6). The method was validated over the range from 0.1 to 50 microg/ml for plasma and amniotic fluid and 0.2-50 microg/ml for the placental and fetal tissues.

Pharmacokinetics of intravenous acyclovir, zidovudine, and acyclovir-zidovudine in pregnant rats

The pharmacokinetics and placental transfer of acyclovir and zidovudine monotherapies and acyclovir-zidovudine combination therapy were compared in the pregnant rat. Timed-pregnancy Sprague-Dawley rats were used for the study. Doses of 60 mg of each drug/kg of body weight in monotherapy and in combination therapy were given by intravenous bolus, and samples of maternal plasma, amniotic fluid, fetal tissue, and placental tissue were collected over a period of 8 h postdose. Concentrations of each drug in the various matrices were measured by high-performance liquid chromatography. All data were analyzed by using WinNonlin. A one-compartment model with first-order elimination was used to fit the AZT plasma data from the combination therapy rats, but the plasma data from the other groups were fit to a two-compartment model. Tissue data were analyzed by noncompartmental analysis to generate area-under-the-concentration-time-curve values. Implementation of the combination therapy altered the pharmacokinetics of each drug compared to its monotherapy pharmacokinetics. The combination of these two drugs may potentiate fetal and amniotic fluid exposures to each drug.

Determination of acyclovir in maternal plasma, amniotic fluid, fetal and placental tissues by high-performance liquid chromatography

Acyclovir [9-[(2-hydroxyethoxy)-methyl]-guanosine, Zovirax, ACV] is a synthetic purine nucleoside analog active against herpes simplex virus types 1 (HSV-1), 2 (HSV-2), and varicella zoster virus. Acyclovir has frequently been used in HSV-2 seropositive mothers to prevent prenatal transmission of herpes virus to their unborn children. A fast and reproducible HPLC method for the determination of the highly polar acyclvoir in maternal rat plasma, amniotic fluid, placental tissue, and fetal tissue has been developed and validated. Plasma and amniotic fluid samples were prepared by protein precipitation using 2 M perchloric acid and syringe filtering. Tissue samples were homogenized in distilled water, centrifuged, and extracted using a C(18) solid-phase extraction method prior to analysis. Baseline resolution was achieved for acyclovir and the internal standard gancyclovir, an anti-viral of similar structure to acyclovir, using an Agilent Eclipse XDB C(8) column (150 x 2.1 mm, 5 microm). The mobile phase used for the plasma and amniotic fluid was 10 mM acetate/citrate buffer-3.7 mM aqueous octanesulfonic acid (87.5:12.5, v/v) at a flow-rate of 0.2 ml/min. The mobile phase used for the tissue samples was 30 mM acetate/citrate buffer with 5 mM octanesulfonic acid-acetonitrile (99:1, v/v). Both aqueous mobile phase portions were pH adjusted to 3.08. All separations were done using an Agilent 1100 Series HPLC system with UV detection of 254 nm. The assay was validated for each matrix over a range of 0.25-100 microg/ml over 3 days using five replicates of three spiked concentrations. The relative standard deviation and percent error for each validation data set was <15% for middle and high quality control (QC) points and <20% for all low QC points. All calibration curves showed good linearity with an R(2)>0.99. The extraction efficiency for recovery of acyclovir from all matrices was >80%.