Pharmacokinetic (PK) and Pharmacodynamic (PD) Modeling of Ampicillin and Gentamicin in Peripartum Patients

Pregnant women who present to Labor and Delivery will be identified as potential participants based on Inclusion/Exclusion criteria and their need to receive Ampicillin and/or Gentamicin therapy. The additional group of 20 non-pregnant women will also be identified based on Inclusion/Exclusion criteria and their need to receive Ampicillin and/or Gentamicin therapy.

Once identified, interested candidates will be fully informed of the study procedures, have all questions answered, and informed consent obtained.

Pregnant participants will receive Ampicillin 2g IV loading dose followed by 1g IV every 4 hrs until delivery; or Ampicillin 2g IV every 6hrs along with Gentamicin 5mg/kg IV every 24 hrs. Dose times will be recorded.

Non-pregnant participants will receive similar doses of either Ampicillin and/or Gentamicin, if not the same dose(s).

Fingerstick blood collection will be drawn from both populations at the following timepoints:

• before the administration of Ampicillin, and/or
• before the administration of Gentamicin
• after the full initial dose of the antibiotic has infused, at 5 min, 15 min, 30 min, 2-3hr, 4-6hr, immediately prior to the next dose of drug, and at DELIVERY (a 5 minute window for each timepoint will be permitted) If delivery occurs prior to the 3 or 6 hr timepoints, fingerstick blood collection should continue

Samples will be obtained on filter paper via the Dry Blood Spot (DBS) method, which is clinically appropriate for the purposes of this study.

Umbilical venous and arterial blood will also be drawn for sampling from the placenta after delivery, and cutting of the umbilical cord.

Inclusion criteria

• Generally healthy, pregnant woman (28-42 weeks)
• Generally healthy, non-pregnant female
• Scheduled to receive Ampicillin and/or Gentamicin IV
• Ages 18-55 years old
• Relatively normal Comprehensive Metabolic Panel (if available), as evidenced by recent blood work
• Able and willing to sign consent

Exclusion criteria

• Women with known renal or hepatic impairment; preeclampsia; Diabetes, including Gestational; any medical condition that, in the opinion of the Investigator or research team member, could potentially interfere with the study objectives
• Women who are participating in another study
• Pregnant with multiples
• BMI > 40