# Impact of clinical preparation steps and use of sex-specific reference for accurate antibiotic monitoring in body fluids

## TL;DR

This study shows that sample preparation steps and using sex-specific urine references improve the accuracy of measuring antibiotics in urine, helping personalize drug dosing for critically ill patients.

## Contribution

The study demonstrates that sex-specific urine references and careful sample handling improve antibiotic quantification accuracy using Raman spectroscopy.

## Key findings

- Freezing, centrifugation, and filtration reduce piperacillin concentration in urine samples.
- Sex-specific urine pools provide more accurate quantification than mixed-sex pools.
- Resonance Raman spectroscopy is effective for measuring piperacillin in clinical urine samples.

## Abstract

Effective antibiotic therapy in critically ill patients requires precise dosing tailored to individual conditions. However, physiological changes in these patients can complicate drug exposure prediction, leading to treatment failure or toxicity. Therapeutic drug monitoring (TDM) is crucial in optimizing antibiotic therapy, with Raman spectroscopy emerging as a promising method due to its speed and sensitivity.

The utility of resonance Raman spectroscopy in analyzing clinical urine samples was investigated, specifically focusing on piperacillin concentrations. Samples subjected to various preparation techniques, including freezing, centrifugation, and filtration, were analyzed using deep UV resonance Raman spectroscopy. Data analysis involved preprocessing and chemometric modeling to assess concentration changes and the influence of sample matrix.

Sample preparation steps induce concentration changes in piperacillin, with freezing having the highest impact. Chemometric modeling reveals that freezing, filtration, and centrifugation, especially when combined, reduce drug concentration. Furthermore, the choice of urine reference for quantification impacts results, with sex-specific urine pools showing better accuracy compared to mixed pools.

Resonance Raman spectroscopy effectively quantifies piperacillin concentrations in urine. Freezing, centrifugation, and filtration during sample preparation influence drug concentration. Using sex-specific urine pools as references yields more accurate quantification results. These findings underscore the importance of considering sample processing effects and reference selection in TDM studies, offering insights for optimizing antibiotic dosing in critically ill patients. Further validation on a larger scale is warranted to confirm these observations.

Domes et al. use enhanced Raman spectroscopy to quantify drugs within body fluids. Freezing, centrifugation, and filtration result in additive loss of piperacillin from human urine, while using a reference urine pool from same-sex donors yield superior results to a mixed-sex urine pool.

It is important to dose people with an appropriate amount of a drug to ensure the drug can work effectively while minimizing side effects. By measuring the amount of antibiotic present in their urine, it is possible to determine whether the correct amount of an antibiotic drug has been given to a patient. The amount of antibiotics present in human urine was compared after various processing steps, such as filtering or freezing, which are often undertaken in hospital laboratories. The processing steps reduced the amounts of antibiotic present. It was also found that more accurate measurements of drugs in urine were made when body fluids from people of the same, rather than the opposite, sex were used as reference. In the future, this method could enable optimal, personalized treatment for various patient populations.