Decreased placental and transcellular permeation of cefuroxime in pregnant women with diabetes

Maternal-Fetal Exposure to Antibiotics: Levels, Mother-to-Child Transmission, and Potential Health Risks

Due to its widespread applications in various fields, antibiotics are continuously released into the environment and ultimately enter the human body through diverse routes. Meanwhile, the unreasonable use of antibiotics can also lead to a series of adverse outcomes. Pregnant women and developing fetuses are more susceptible to the influence of external chemicals than adults. The evaluation of antibiotic exposure levels through questionnaire surveys or prescriptions in medical records and biomonitoring-based data shows that antibiotics are frequently prescribed and used by pregnant women around the world. Antibiotics may be transmitted from mothers to their offspring through different pathways, which then adversely affect the health of offspring. However, there has been no comprehensive review on antibiotic exposure and mother-to-child transmission in pregnant women so far. Herein, we summarized the exposure levels of antibiotics in pregnant women and fetuses, the exposure routes of antibiotics to pregnant women, and related influencing factors. In addition, we scrutinized the potential mechanisms and factors influencing the transfer of antibiotics from mother to fetus through placental transmission, and explored the adverse effects of maternal antibiotic exposure on fetal growth and development, neonatal gut microbiota, and subsequent childhood health. Given the widespread use of antibiotics and the health threats posed by their exposure, it is necessary to comprehensively track antibiotics in pregnant women and fetuses in the future, and more in-depth biological studies are needed to reveal and verify the mechanisms of mother-to-child transmission, which is crucial for accurately quantifying and evaluating fetal health status.

Application of a Physiologically Based Pharmacokinetic Model to Predict Cefazolin and Cefuroxime Disposition in Obese Pregnant Women Undergoing Caesarean Section

Intravenous (IV) cefuroxime and cefazolin are used prophylactically in caesarean sections (CS). Currently, there are concerns regarding sub-optimal dosing in obese pregnant women compared to lean pregnant women prior to CS. The current study used a physiologically based pharmacokinetic (PBPK) approach to predict cefazolin and cefuroxime pharmacokinetics in obese pregnant women at the time of CS as well as the duration that these drug concentrations remain above a target concentration (2, 4 or 8 µg/mL or µg/g) in plasma or adipose tissue. Cefazolin and cefuroxime PBPK models were first built using clinical data in lean and in obese non–pregnant populations. Models were then used to predict cefazolin and cefuroxime pharmacokinetics data in lean and obese pregnant populations. Both cefazolin and cefuroxime models sufficiently described their total and free levels in the plasma and in the adipose interstitial fluid (ISF) in non–pregnant and pregnant populations. The obese pregnant cefazolin model predicted adipose exposure adequately at different reference time points and indicated that an IV dose of 2000 mg can maintain unbound plasma and adipose ISF concentration above 8 µg/mL for 3.5 h post dose. Predictions indicated that an IV 1500 mg cefuroxime dose can achieve unbound plasma and unbound ISF cefuroxime concentration of ≥8 µg/mL up to 2 h post dose in obese pregnant women. Re-dosing should be considered if CS was not completed within 2 h post cefuroxime administration for both lean or obese pregnant if cefuroxime concentrations of ≥8 µg/mL is required. A clinical study to measure cefuroxime adipose concentration in pregnant and obese pregnant women is warranted.

Prediction of Maternal and Fetoplacental Concentrations of Cefazolin, Cefuroxime, and Amoxicillin during Pregnancy Using Bottom-Up Physiologically Based Pharmacokinetic Models

Concerns over maternal and fetal drug exposures highlight the need for a better understanding of drug distribution into the fetus through the placental barrier. This study aimed to predict maternal and fetal drug disposition using physiologically based pharmacokinetic (PBPK) modeling. The detailed maternal-placental-fetal PBPK model within the Simcyp Simulator V20 was used to predict the maternal and fetoplacental exposure of cefazolin, cefuroxime, and amoxicillin during pregnancy and at delivery. The mechanistic dynamic model includes physiologic changes of the maternal, fetal, and placental parameters over the course of pregnancy. Placental kinetics were parametrized using permeability parameters determined from the physicochemical properties of these compounds. Then, the PBPK predictions were compared with the observed data. Fully bottom-up fetoplacental PBPK models were developed for cefuroxime, cefazolin, and amoxicillin without any parameter fitting. Predictions in nonpregnant subjects and in pregnant subjects fall within 2-fold of the observed values. Predictions matched observed pharmacokinetic data reported in nine maternal (five fetoplacental) studies for cefuroxime, 10 maternal (five fetoplacental) studies for cefazolin, and six maternal (two fetoplacental) studies for amoxicillin. Integration of the fetal and maternal system parameters within PBPK models, together with compound-related parameters used to calculate placental permeability, facilitates and extends the applications of the maternal-placental-fetal PBPK model. The developed model can also be used for designing clinical trials and prospectively used for maternal-fetal risk assessment after maternally administered drugs or unintended exposure to environmental toxicants. SIGNIFICANCE STATEMENT: This study investigates the performance of an integrated maternal-placental-fetal PBPK model to predict maternal and fetal tissue exposure of renally eliminated antibiotics that cross the placenta through a passive diffusion mechanism. The transplacental permeability clearance was predicted from the drug physicochemical properties. Results demonstrate that the PBPK approach can facilitate the prediction of maternal and fetal drug exposure simultaneously at any gestational age to support its use in the maternal-fetal exposure assessments.

Preliminary physiologically based pharmacokinetic modeling of renally cleared drugs in Chinese pregnant women

AIM

The aim of this study was to build and verify a preliminary physiologically based pharmacokinetic (PBPK) model of Chinese pregnant women. The model was used to predict maternal pharmacokinetics (PK) of 6 predominantly renally cleared drugs.

METHOD

Based on SimCYP Caucasian pregnancy population dataset, the preliminary Chinese pregnant population was built by updating several key parameters and equations according to physiological parameters of Chinese (or Japanese) pregnant women. Drug-specific parameters of 6 renally cleared drugs were validated through PBPK modeling of Caucasian non-pregnant, Caucasian pregnant and Chinese non-pregnant population. The preliminary PBPK model of Chinese pregnant population was then developed by integrating the preliminary Chinese pregnant population and the drug-specific parameters. This model was verified by comparing the predicted maternal PK of these 6 drugs with the observed in vivo data from the literature.

RESULTS

The preliminary Chinese pregnant population PBPK model successfully predicted the PK of 6 target drugs for different pregnancy stages. The predicted plasma concentrations time profiles fitted the observed data well, and most predicted PK parameters were within 2-fold of observed data.

CONCLUSIONS

The preliminary Chinese pregnant population PBPK model provided a useful tool to predict the maternal PK of 6 predominantly renally cleared drugs in Chinese pregnant women.

Intrapartum beta-lactam antibiotics for preventing group B streptococcal early-onset disease: can we abandon the concept of 'inadequate' intrapartum antibiotic prophylaxis?

Introduction: Neonatal sepsis remains a serious and potentially fatal illness. Intrapartum antibiotic prophylaxis (IAP) prevents group B streptococcal (GBS) early-onset sepsis. The optimal duration of IAP (adequate IAP) to reduce vertical transmission of GBS has been debated. Understanding the mechanism of action of IAP may help in minimizing neonatal evaluation and unnecessary antibiotic use.Areas covered: In recent years, several studies on pharmacokinetics and clinical use of IAP have been published. Although penicillin and ampicillin are the most preferred antibiotics, the clinical efficacy of non-beta-lactam antibiotics, including clindamycin and vancomycin, used in cases of penicillin anaphylaxis-associated allergy, remains debatable. This is a narrative review of the literature regarding the impact of 'inadequate' IAP on the clinical management of women and newborns.Expert opinion: Recent evidence suggests that 'inadequate' IAP with beta-lactams is more effective in preventing vertical transmission of GBS than previously thought. Newborns exposed to intrapartum beta-lactams and who are asymptomatic at birth are likely uninfected, irrespective of IAP duration before delivery. Hence, we may abandon the concept of 'inadequate' IAP with beta-lactams in early-onset GBS sepsis, relying primarily on clinical signs observed at birth for managing IAP-exposed neonates.

Efficacy of perioperative cefuroxime as a prophylactic antibiotic in women requiring caesarean section: A systematic review

Intravenous (IV) Cefuroxime (CFX) is widely used in Caesarean Section (CS) as a prophylactic antibiotic. The objective of this systematic review to compare CFX concentration in maternal blood and adipose tissue with the incidence of surgical site infection (SSI) following IV CFX in non-obese and obese women undergoing CS. A search in Medline, EMBASE, Cochrane, Web of Science, CINHAL Plus, Scopus and Google Scholar was conducted without language or date restrictions. Published articles or abstracts reporting CFX concentration or rates of SSI following CFX IV administration in adult women requiring CS were included. Studies were screened by title and abstract. Quality of studies was assessed via the ClinPK Statement checklist (Pharmacokinetics studies), or Joanna Briggs Institute Critical Appraisal Tools (SSI studies). The Cochrane Effective Practice and Organisation of Care checklist evaluated the risk of bias (SSI studies). There were no studies evaluating CFX concentrations in obese women undergoing CS. For non-obese women, CFX plasma concentrations ranged from 9.85 to 95.25 mg/L within 30-60 min of administration (1500 mg dose; 4 articles, n = 108 women). Plasma CFX concentrations were above the minimum inhibitory concentration (8 mg/L) for up to 3 h post-dose. No studies reported on CFX concentration in adipose tissue. Reported rates of SSI were 4.7% and 6.8% after administration of a single 1500 mg dose of CFX administrated after cord clamping (n = 144 women). There is limited data on pharmacokinetics of CFX for CS. There were no studies that reported CFX concentrations or SSI in obese women.

The transplacental passage of commonly used intrapartum antibiotics and its impact on the newborn management: A narrative review

Neonates exposed to intra-amniotic infection are at increased risk of early-onset sepsis. Administration of antibiotics to the mother may offer some protection, however a comprehensive description of the determinants influencing their transplacental passage and delivery to the fetus has not been performed. While penicillin G, ampicillin, cefazolin and gentamicin reach therapeutic levels in the fetal serum rapidly following maternal administration, the transfer of second-line intrapartum antimicrobials, such as vancomycin and clindamycin, is slower and less predictable. Erythromycin, used in the context of preterm premature rupture of the membranes, has suboptimal influx into the fetal compartment. This evidence is predominantly drawn from term pregnancies and situations of low infectious risk; however, prematurity may negatively influence fetal exposure to intrapartum antibiotics. Optimal fetal antimicrobial concentrations to target are poorly defined and the extent to which our review findings apply to preterm early-onset neonatal sepsis prevention is unclear. Interpretation of blood cultures drawn in neonates with expected circulating levels of maternal antimicrobials above the minimal inhibitory concentration for Group B Streptococcus is challenging despite the use of contemporary optimized blood culture media.

The Effect of Diabetes and Hypertension on the Placental Permeation of the Hydrophilic Drug, Ranitidine

INTRODUCTION

Ranitidine is a hydrophilic weak base and an H₂-receptor antagonist which is commonly used for gastroesophageal reflux, including during pregnancy. It has limited placental permeation and can be used as a pre-anesthetic antacid to prevent aspiration of acidic stomach contents. Recent studies suggest that diabetes and hypertension may influence placental permeation of hydrophilic drugs. Thus, this study aimed to investigate the influence of diabetes and hypertension on ranitidine's placental permeation in pregnant women.

METHODS

Forty one pregnant women all scheduled for elective cesarean section entered the study: healthy control (n = 15), with hypertension (n = 16) and with gestational diabetes (n = 10). All women received 50 mg of ranitidine intravenously. Three samples of maternal plasma (after ranitidine application, at delivery and after delivery), and two umbilical cord samples (arterial and venous blood) were collected and analyzed for ranitidine concentrations. Maternal pharmacokinetic parameter were calculated as well as feto:maternal and umbilical cord arterial to venous concentration ratios.

RESULTS

Ranitidine maternal and umbilical cord (arterial and venous) concentrations were similar in all three groups and there were no difference between feto:maternal ratios nor volume of distribution, clearance and half life between the groups.

DISCUSSION

Fetal concentrations are dependent on maternal concentrations in healthy and hypertensive women but not in diabetic women. Hypertension and diabetes did not affect fetal handling of ranitidine. Though hypertension and diabetes did not influence ranitidine placental permeation, it appears they altered time needed to achieve unity between maternal and fetal plasma.