Albuterol delivery in an in vitro pediatric ventilator lung model: comparison of jet, ultrasonic, and mesh nebulizers.

OBJECTIVE: To determine the influence of nebulizer types and nebulization modes on bronchodilator delivery in a mechanically ventilated pediatric lung model. DESIGN: In vitro, laboratory study. SETTING: Research laboratory of a university hospital. INTERVENTIONS: Using albuterol as a marker, three nebulizer types (jet nebulizer, ultrasonic nebulizer, and vibrating-mesh nebulizer) were tested in three nebulization modes in a nonhumidified bench model mimicking the ventilatory pattern of a 10-kg infant. The amounts of albuterol deposited on the inspiratory filters (inhaled drug) at the end of the endotracheal tube, on the expiratory filters, and remaining in the nebulizers or in the ventilator circuit were determined. Particle size distribution of the nebulizers was also measured. MEASUREMENTS AND MAIN RESULTS: The inhaled drug was 2.8% ± 0.5% for the jet nebulizer, 10.5% ± 2.3% for the ultrasonic nebulizer, and 5.4% ± 2.7% for the vibrating-mesh nebulizer in intermittent nebulization during the inspiratory phase (p < 0.01). The most efficient nebulizer was the vibrating-mesh nebulizer in continuous nebulization (13.3% ± 4.6%, p < 0.01). Depending on the nebulizers, a variable but important part of albuterol was observed as remaining in the nebulizers (jet and ultrasonic nebulizers), or being expired or lost in the ventilator circuit (all nebulizers). Only small particles (range 2.39-2.70 µm) reached the end of the endotracheal tube. CONCLUSIONS: Important differences between nebulizer types and nebulization modes were seen for albuterol deposition at the end of the endotracheal tube in an in vitro pediatric ventilator-lung model. New aerosol devices, such as ultrasonic and vibrating-mesh nebulizers, were more efficient than the jet nebulizer.

Development of a generic approach for monitoring leachable compounds in hospital pharmacy-prepared prefilled plastic packaging by ultrahigh-performance liquid chromatography coupled to high-resolution mass spectrometry with postcolumn infusion.

Prefilled plastic packaging is time- and cost-effective in hospital pharmacy because it prevents waste, preparation errors, dosage errors, microbial contamination and accidents. This packaging mostly includes prefilled syringes (PFS), intravenous (IV) bags and vials intended for long-term storage that can be used for immediate treatment. There is a rising availability in the market for prefilled drug products due to their practical approach. Leachable compounds could be evaluated in hospital pharmacy-prepared prefilled drug solutions. The Pharmacy Department at the Lausanne University Hospital has developed an innovative, highly sensitive, and generic method by postcolumn infusion based on ultrahigh-performance liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS) for the analysis of plastic additives in hospital pharmacies. The postcolumn infusion solution was developed with 2% ammonium hydroxide in methanol on a representative set of 30 candidate compounds with different physical-chemical properties, such as log P and molecular structure, to represent the most important categories of additives. The LODs obtained for all compounds ranged from 0.03 to 7.91 ng/mL with linearity up to 250 ng/mL. Through this screening method, plastic additives can be rapidly identified due to the combined use of retention time, exact mass (including isotopic pattern) and MS/MS spectra. In addition, the users can screen for vast categories of plastic additives, including plasticizers, epoxy monomers, antioxidants, UV stabilizers, and others. The screening is facilitated by assessments of a complex in-house-built database for extractable and leachable trace assessment (DELTA), containing 205 compounds for unambiguous identification. Relative response factors were established for all analytes to obtain a semiquantitation of compounds. Moreover, the database also contains valuable estimative toxicology information, which was obtained through calculating their permissible dose exposure threshold; thus, estimative toxicology assessment can be performed for identified compounds in prefilled drug products. This method and the database were applied to a hospital pharmacy-prepared prefilled vancomycin syringe for paediatric use. Ultrasound-assisted dispersive liquid-liquid microextraction (UA-DLLME) was used to prepare the samples for leachable analysis. As a result, 17 plastic additives were formally identified, and their concentrations were estimated. A toxicology assessment was performed by comparing their concentrations with their theoretical PDE thresholds. In conclusion, the prefilled drug solution released a negligible amount of known leachables that appeared to be safe for use in neonates and children.

A highly sensitive LC-tandem MS assay for the measurement in plasma and in urine of salbutamol administered by nebulization during mechanical ventilation in healthy volunteers.

The new-generation nebulizers are commonly used for the administration of salbutamol in mechanically ventilated patients. The different modes of administration and new devices have not been compared. We developed a liquid chromatography-tandem mass spectrometry method for the determination of concentrations as low as 0.05 ng/mL of salbutamol, corresponding to the desired plasma concentration after inhalation. Salbutamol quantification was performed by reverse-phase HPLC. Analyte quantification was performed by electrospray ionization-triple quadrupole mass spectrometry using selected reaction monitoring detection ESI in the positive mode. The method was validated over concentrations ranging from 0.05 to 100 ng/mL in plasma and from 0.18 to 135 ng/mL in urine. The method is precise, with mean inter-day coefficient of variation (CV%) within 3.1-8.3% in plasma and 1.3-3.9% in urine, as well as accurate. The proposed method was found to reach the required sensitivity for the evaluation of different nebulizers as well as nebulization modes. The present assay was applied to examine whether salbutamol urine levels, normalized with the creatinine levels, correlated with the plasma concentrations. A suitable, convenient and noninvasive method of monitoring patients receiving salbutamol by mechanical ventilation could be implemented.

Quality and safety of parenteral nutrition for newborn and preterm infants as an on-ward preparation.

BACKGROUND: For newborn and preterm infants, standardised and individual parenteral nutrition (PN) is used. PN preparation is at risk for contamination and dosing errors. The quality of PN is crucial for infants and has a direct impact on their health status and safety. PURPOSE: The aim of this study is to evaluate the physicochemical and microbial quality of PN for newborn and preterm infants prepared on a neonatal ward. METHODS: Sampling of various individual PN prepared by nurses on a neonatal ward was performed. Formulations included maximal four electrolytes, variable dextrose and amino acid concentrations. Depending on the sample volume, up to three quality analyses were performed: (1) test for bacterial endotoxins by kinetic-chromogenic method, (2) sterility according to the European and US Pharmacopoeia, and (3) quantification of electrolytes by capillary electrophoresis and of dextrose by ultraviolet detection after enzymatic reaction of hexokinase. The concentrations obtained were evaluated based on the US and Swiss Pharmacopoeia specifications for compounded preparations and compared to the widened pharmacy specifications. RESULTS: The composition of 86% of the 110 analysed PN prepared by nurses on the neonatal ward corresponded to their medical prescription. 14% were out of the acceptable widened pharmacy ranges. We found no microbial contamination in the samples. All PN were free from endotoxins. CONCLUSION: Component concentrations of PN prepared on wards by nurses differed frequently and significantly from their medical prescription, and the deviation can be critical depending on the component and its mode of action. The sample size is too small to evaluate the microbial contamination.

The bioavailability of bromazepam, omeprazole and paracetamol given by nasogastric feeding tube.

AIMS: To characterize and compare the pharmacokinetic profiles of bromazepam, omeprazole and paracetamol when administered by the oral and nasogastric routes to the same healthy cohort of volunteers. METHODS: In a prospective, monocentric, randomized crossover study, eight healthy volunteers received the three drugs by the oral (OR) and nasogastric routes (NT). Sequential plasma samples were analyzed by high-performance liquid chromatography-UV, pharmacokinetic parameters (Cmax, AUC(0-infinity), t(1/2), k(e), tmax) were compared statistically, and Cmax, AUC(0-infinity) and t(max) were analyzed for bioequivalence. RESULTS: A statistically significant difference was seen in the AUC(0-infinity) of bromazepam, with nasogastric administration decreasing availability by about 25%: AUC(OR) = 2501 ng mL(-1) h; AUC(NT) = 1855 ng mL(-1) h (p < 0.05); ratio (geometric mean) = 0.74 [90% confidence interval (CI) 0.64-0.87]. However, this does not appear to be clinically relevant given the usual dosage range and the drug's half-life (approx. 30 h). A large interindividual variability in omeprazole parameters prevented any statistical conclusion from being drawn in terms of both modes of administration despite their similar average profile: AUC(OR) = 579 ng mL(-1) h; AUC(NT) = 587 ng mL(-1) h (p > 0.05); ratio (geometric mean) = 1.01 (90% CI 0.64-1.61). An extended study with a larger number of subjects may possibly provide clearer answers. The narrow 90% confidence limits of paracetamol indicate bioequivalence: AUC(OR) = 37 microg mL(-1) h; AUC(NT) = 41 microg mL(-1) h(p > 0.05); ratio (geometric mean) = 1.12 (90% CI 0.98-1.28). CONCLUSION: The results of this study show that the nasogastric route of administration does not appear to cause marked, clinically unsuitable alterations in the bioavailability of the tested drugs.

Stability of prostaglandin E1 solutions stored in polypropylene syringes for continuous intravenous administration to newborns.

OBJECTIVE: We aimed to monitor the physicochemical stability of prostaglandin E1 (PGE1) 1.5 and 15 µg/mL in 10% dextrose stored in polypropylene syringes. METHODS: We developed a liquid chromatography-high resolution mass spectrometry (LC-HRMS) method to detect and quantify levels of PGE1. Method selectivity was performed with a mixture of PGE1 and its degradation products. Forced degradation tests were performed to determine which degradation products were most likely to form. PGE1 injection solutions in 10% dextrose were stored in unprotected and shielded-from-light polypropylene syringes in a climatic chamber. Samples were taken immediately after preparation (T0) and after 24, 48, 72 and 168 hours for analysis. PGE1 solutions were considered stable if ≥90.0% of the initial concentration was retained. RESULTS: The LC-HRMS method was validated in the range of 0.086-0.200µg/mL PGE1 with trueness values between 98.2% and 100.3%, and repeatability and intermediate precision values of <2.2%and <4.7%, respectively. The quantification and detection limits of the method were 0.086 and 0.026µg/mL, respectively. PGE1 and its degradation products were resolved chromatographically. PGE1 injection solutions were≥90.0%stable after 48hours in unprotected from light (UPL) syringes. The solutions remained clear without precipitation, colour or pH modification and subvisible particles within the permitted levels. Prostaglandin A1 was the sole degradation product observed. CONCLUSIONS: A LC-HRMS method to evaluate PGE1 stability in a 10% dextrose was developed and validated. PGE1 1.5 and 15µg/mL in 10% dextrose solution are stable for 48hours when stored at 30ºC in UPL polypropylene syringes.

Physicochemical aspects and efficiency of albuterol nebulization: comparison of three aerosol types in an in vitro pediatric model.

BACKGROUND: Advances in nebulizer design have produced both ultrasonic nebulizers and devices based on a vibrating mesh (vibrating mesh nebulizers), which are expected to enhance the efficiency of aerosol drug therapy. The aim of this study was to compare 4 different nebulizers, of 3 different types, in an in vitro model using albuterol delivery and physical characteristics as benchmarks. METHODS: The following nebulizers were tested: Sidestream Disposable jet nebulizer, Multisonic Infra Control ultrasonic nebulizer, and the Aerogen Pro and Aerogen Solo vibrating mesh nebulizers. Aerosol duration, temperature, and drug solution osmolality were measured during nebulization. Albuterol delivery was measured by a high-performance liquid chromatography system with fluorometric detection. The droplet size distribution was analyzed with a laser granulometer. RESULTS: The ultrasonic nebulizer was the fastest device based on the duration of nebulization; the jet nebulizer was the slowest. Solution temperature decreased during nebulization when the jet nebulizer and vibrating mesh nebulizers were used, but it increased with the ultrasonic nebulizer. Osmolality was stable during nebulization with the vibrating mesh nebulizers, but increased with the jet nebulizer and ultrasonic nebulizer, indicating solvent evaporation. Albuterol delivery was 1.6 and 2.3 times higher with the ultrasonic nebulizer and vibrating mesh nebulizers devices, respectively, than with the jet nebulizer. Particle size was significantly higher with the ultrasonic nebulizer. CONCLUSIONS: The in vitro model was effective for comparing nebulizer types, demonstrating important differences between nebulizer types. The new devices, both the ultrasonic nebulizers and vibrating mesh nebulizers, delivered more aerosolized drug than traditional jet nebulizers.