Concentration profile of tobramycin in exhaled breath condensate after inhalation of a single dose: A pilot study

Implementation of green-assessed nanotechnology and quality by design approach for development of optical sensor for determination of tobramycin in ophthalmic formulations and spiked human plasma

A fast eco-friendly colorimetric method was developed for the determination of Tobramycin in drug substance, ophthalmic formulations, and spiked human plasma using silver nanoparticles optical sensor. Even though tobramycin is non-UV-visible absorbing, the developed method is based on measuring the absorbance quenching of silver nanoparticles resulting from the interaction with tobramycin. Different factors affecting the absorbance intensity were studied as; silver nanoparticle concentration, pH, buffer type, and reaction time using quality by design approach. Validation of the proposed method was performed according to ICH guidelines and was found to be accurate, precise, and sensitive. The linearity range of tobramycin was 0.35-4.0 μg/mL. The optical sensor was successfully applied for the determination of Tobramycin in ophthalmic formulations and spiked human plasma without pre-treatment. Additionally, the binding between Tobramycin and PVP- capped silver nanoparticles was studied using molecular docking software. The method was assessed and compared to colorimetric reported methods for the green character using Green Analytical Procedure Index (GAPI) and Analytical GREEnness calculator (AGREE) tools and found to be greener.

Beta-Lactam Antibiotics Can Be Measured in the Exhaled Breath Condensate in Mechanically Ventilated Patients: A Pilot Study

Different techniques have been proposed to measure antibiotic levels within the lung parenchyma; however, their use is limited because they are invasive and associated with adverse effects. We explore whether beta-lactam antibiotics could be measured in exhaled breath condensate collected from heat and moisture exchange filters (HMEFs) and correlated with the concentration of antibiotics measured from bronchoalveolar lavage (BAL). We designed an observational study in patients undergoing mechanical ventilation, which required a BAL to confirm or discard the diagnosis of pneumonia. We measured and correlated the concentration of beta-lactam antibiotics in plasma, epithelial lining fluid (ELF), and exhaled breath condensate collected from HMEFs. We studied 12 patients, and we detected the presence of antibiotics in plasma, ELF, and HMEFs from every patient studied. The concentrations of antibiotics were very heterogeneous over the population studied. The mean antibiotic concentration was 293.5 (715) ng/mL in plasma, 12.3 (31) ng/mL in ELF, and 0.5 (0.9) ng/mL in HMEF. We found no significant correlation between the concentration of antibiotics in plasma and ELF (R² = 0.02, p = 0.64), between plasma and HMEF (R² = 0.02, p = 0.63), or between ELF and HMEF (R² = 0.02, p = 0.66). We conclude that beta-lactam antibiotics can be detected and measured from the exhaled breath condensate accumulated in the HMEF from mechanically ventilated patients. However, no correlations were observed between the antibiotic concentrations in HMEF with either plasma or ELF.

A new method for investigating bioequivalence of inhaled formulations: A pilot study on salbutamol

Purpose: An efficient, cost-effective and non-invasive test is required to overcome the challenges faced in the process of bioequivalence (BE) studies of various orally inhaled drug formulations. Two different types of pressurized meter dose inhalers (MDI-1 and MDI-2) were used in this study to test the practical applicability of a previously proposed hypothesis on the BE of inhaled salbutamol formulations. Methods: Salbutamol concentration profiles of the exhaled breath condensate (EBC) samples collected from volunteers receiving two inhaled formulations were compared employing BE criteria. In addition, the aerodynamic particle size distribution of the inhalers was determined by employing next generation impactor. Salbutamol concentrations in the samples were determined using liquid and gas chromatographic methods. Results: The MDI-1 inhaler induced slightly higher EBC concentrations of salbutamol when compared with MDI-2. The geometric MDI-2/MDI-1 mean ratios (confidence intervals) were 0.937 (0.721-1.22) for maximum concentration and 0.841 (0.592-1.20) for area under the EBC-time profile, indicating a lack of BE between the two formulations. In agreement with the in vivo data, the in vitro data indicated that the fine particle dose (FPD) of MDI-1 was slightly higher than that for the MDI-2 formulation. However, the FPD differences between the two formulations were not statistically significant. Conclusion: EBC data of the present work may be considered as a reliable source for assessment of the BE studies of orally inhaled drug formulations. However, more detailed investigations employing larger sample sizes and more formulations are required to provide more evidence for the proposed method of BE assay.

Understanding the suitability of established antibiotics for oral inhalation from a pharmacokinetic perspective: an integrated model-based investigation based on rifampicin, ciprofloxacin and tigecycline in vivo data

BACKGROUND

Treating pulmonary infections by administering drugs via oral inhalation represents an attractive alternative to usual routes of administration. However, the local concentrations after inhalation are typically not known and the presumed benefits are derived from experiences with drugs specifically optimized for inhaled administration.

OBJECTIVES

A physiologically based pharmacokinetic/pharmacodynamic (PBPK/PD) model was developed to elucidate the pulmonary PK for ciprofloxacin, rifampicin and tigecycline and link it to bacterial PK/PD models. An exemplary sensitivity analysis was performed to potentially guide drug optimization regarding local efficacy for inhaled antibiotics.

METHODS

Detailed pulmonary tissue, endothelial lining fluid and systemic in vivo drug concentration-time profiles were simultaneously measured for all drugs in rats after intravenous infusion. Using this data, a PBPK/PD model was developed, translated to humans and adapted for inhalation. Simulations were performed comparing potential benefits of oral inhalation for treating bronchial infections, covering intracellular pathogens and bacteria residing in the bronchial epithelial lining fluid.

RESULTS

The PBPK/PD model was able to describe pulmonary PK in rats. Often applied optimization parameters for orally inhaled drugs (e.g. high systemic clearance and low oral bioavailability) showed little influence on efficacy and instead mainly increased pulmonary selectivity. Instead, low permeability, a high epithelial efflux ratio and a pronounced post-antibiotic effect represented the most impactful parameters to suggest a benefit of inhalation over systemic administration for locally acting antibiotics.

CONCLUSIONS

The present work might help to develop antibiotics for oral inhalation providing high pulmonary concentrations and fast onset of exposure coupled with lower systemic drug concentrations.

Exhaled breath condensate efficacy to identify mutations in patients with lung cancer: A pilot study

Exhaled breath condensate (EBC) is used to investigate the efficacy of EBC to detect the genetic mutations in patients with lung cancer. Samples of 5 patients and 5 healthy volunteers were collected. DNA was extracted and used for amplification of hotspot regions of TP53 and KRAS genes by using PCR. We performed the mutation analysis by direct sequencing in all subjects. Detected mutations in EBC samples were compared with those of corresponding tumor tissues and there was complete agreement within the detected mutations in EBC and tumorous tissue. EBC can be used as an efficient and noninvasive source for the assessment of gene mutations in patients with lung cancer.

Biosensor-Enabled Multiplexed On-Site Therapeutic Drug Monitoring of Antibiotics

Personalized antibiotherapy ensures that the antibiotic concentration remains in the optimal therapeutic window to maximize efficacy, minimize side effects, and avoid the emergence of drug resistance due to insufficient dosing. However, such individualized schemes need frequent sampling to tailor the blood antibiotic concentrations. To optimally integrate therapeutic drug monitoring (TDM) into the clinical workflow, antibiotic levels can either be measured in blood using point-of-care testing (POCT), or can rely on noninvasive sampling. Here, a versatile biosensor with an antibody-free assay for on-site TDM is presented. The platform is evaluated with an animal study, where antibiotic concentrations are quantified in different matrices including whole blood, plasma, urine, saliva, and exhaled breath condensate (EBC). The clearance and the temporal evaluation of antibiotic levels in EBC and plasma are demonstrated. Influence of matrix effects on measured drug concentrations is determined by comparing the plasma levels with those in noninvasive samples. The system's potential for blood-based POCT is further illustrated by tracking ß-lactam concentrations in untreated blood samples. Finally, multiplexing capabilities are explored successfully for multianalyte/sample analysis. By enabling a rapid, low-cost, sample-independent, and multiplexed on-site TDM, this system can shift the paradigm of "one-size-fits-all" strategy.