A liquid chromatography method with single quadrupole mass spectrometry for quantitative determination of indomethacin in maternal plasma and urine of pregnant patients

Drug development research in pregnant and lactating women

Pregnant and lactating women are considered "therapeutic orphans" because they generally have been excluded from clinical drug research and the drug development process owing to legal, ethical, and safety concerns. Most medications prescribed for pregnant and lactating women are used "off-label" because most of the clinical approved medications do not have appropriate drug labeling information for pregnant and lactating women. Medications that lack human safety data on use during pregnancy and lactation may pose potential risks for adverse effects in pregnant and lactating women as well as risks of teratogenic effects to their unborn and newborn babies. Federal policy requiring the inclusion of women in clinical research and trials led to considerable changes in research design and practice. Despite more women being included in clinical research and trials, the inclusion of pregnant and lactating women in drug research and clinical trials remains limited. A recent revision to the "Common Rule" that removed pregnant women from the classification as a "vulnerable" population may change the culture of drug research and drug development in pregnant and lactating women. This review article provides an overview of medications studied by the Obstetric-Fetal Pharmacology Research Units Network and Centers and describes the challenges in current obstetrical pharmacology research and alternative strategies for future research in precision therapeutics in pregnant and lactating women. Implementation of the recommendations of the Task Force on Research Specific to Pregnant Women and Lactating Women can provide legislative requirements and opportunities for research focused on pregnant and lactating women.

Single- and multiple-dose pharmacokinetics and tolerability of limaprost in healthy Chinese subjects

BACKGROUND AND OBJECTIVES

Limaprost, a prostaglandin E1 analogue, is used to treat various symptoms in patients with ischemic diseases. The present study was designed to determine the pharmacokinetics and tolerability of single and multiple oral doses of limaprost 5 μg tablets in healthy Chinese subjects.

METHODS

Single and multiple doses of 5-μg limaprost were orally administered to 12 healthy Chinese subjects. There was a 2-week washout period between single and multiple dosing. Blood samples were collected at various times. Indomethacin and aspirin were added to the blood samples to inhibit the endogenous release of prostaglandins during the sample processing. Plasma limaprost was measured by a two-dimensional liquid chromatography-tandem mass spectrometry method.

RESULTS

After single dosing, limaprost was rapidly absorbed (time to reach maximum plasma concentration [t max] = 22.50 min) and eliminated (elimination half-life [t ½] = 21.70 min), with the maximum plasma concentration (C max) being 2.56 pg/mL and area under the concentration-time curve (AUC) from time 0 to the last quantifiable time point (AUC0-t) being 70.68 pg·min/mL. There were significant inter-individual variations in the AUCs for both single- and multiple-dose regimens. The values of C max, AUC, t ½ and t max were not statistically different between single and multiple dosing. The accumulation factor R was 0.609 ± 0.432 (R < 1), indicating that there was no accumulation after multiple dosing. There were no statistically significant differences in pharmacokinetic parameters for both single and multiple dosing between female and male subjects. The drug was well tolerated, with no severe adverse events being observed.

CONCLUSIONS

Limaprost is rapidly absorbed after oral administration and is rapidly eliminated, with no accumulation after multiple dosing. The drug is well tolerated and no serious adverse events occurred.

Pharmacokinetics of indomethacin in pregnancy

BACKGROUND AND OBJECTIVES

Although indomethacin has been widely used for the treatment of preterm labor over the past 40 years, there are few reports regarding its pharmacokinetics in pregnant women.

METHODS

This opportunistic study assessed the steady-state pharmacokinetics of indomethacin in pregnant subjects to whom an oral dose of 25 mg every 6 h was prescribed. Indomethacin concentrations in plasma and urine were analyzed by a validated high-performance liquid chromatography method with mass spectrometric detection.

RESULTS

The mean area under the plasma concentration versus time curve at steady state (AUCss) was 1.91 ± 0.53 μg·h/mL, mean peak plasma concentration (C max) was 1.02 ± 0.49 μg/mL, and mean time to reach C max (t max) was 1.3 ± 0.7 h. The mean apparent clearance at steady state was 14.5 ± 5.5 L/h, which is higher than the apparent clearance reported in the literature for non-pregnant subjects. Indomethacin crosses the placenta; the mean fetal/maternal ratio from five sets of cord blood samples collected at delivery was 4.0 ± 1.1.

CONCLUSIONS

Further studies are needed to determine whether any dose adjustments are necessary as a result of the increased clearance of indomethacin during pregnancy.