Stability and assessment of amino acids in parenteral nutrition solutions

Discovery of Glycation Products: Unraveling the Unknown Glycation Space Using a Mass Spectral Library from In Vitro Model Systems

The nonenzymatic reaction between amino acids (AAs) and reducing sugars, also known as the Maillard reaction, is the primary source of free glycation products (GPs) in vivo and in vitro. The limited number of MS/MS records for GPs in public libraries hinders the annotation and investigation of nonenzymatic glycation. To address this issue, we present a mass spectral library containing the experimental MS/MS spectra of diverse GPs from model systems. Based on the conceptional reaction processes and structural characteristics of products, we classified GPs into common GPs (CGPs) and modified AAs (MAAs). A workflow for annotating GPs was established based on the structural and fragmentation patterns of each GP type. The final spectral library contains 157 CGPs, 499 MAAs, and 2426 GP spectra with synthetic model system information, retention time, precursor m/z, MS/MS, and annotations. As a proof-of-concept, we demonstrated the use of the library for screening GPs in unidentified spectra of human plasma and urine. The AAs with the C6H10O5 modification, fructosylation from Amadori rearrangement, were the most found GPs. With the help of the model system, we confirmed the existence of C6H10O5-modified Valine in human plasma by matching both retention time, MS1, and MS/MS without reference standards. In summary, our GP library can serve as an online resource to quickly screen possible GPs in an untargeted metabolomics workflow, furthermore with the model system as a practical synthesis method to confirm their identity.

Y-Site Compatibility Studies of Parenteral Nutrition and Other Intravenous Medications in Neonatal and Pediatric Patients: A Review of the Literature Evidence

BACKGROUND

Polytherapy in neonatal and pediatric patients requiring parenteral nutrition (PN) administration is a challenging task. Due to limited intravenous access, the Y-site administration of medication with PN admixtures is sometimes inevitable.

AIM

This review aims to summarize the evidence on the compatibility of the Y-site of intravenous medications and PN admixtures in neonatal and pediatric settings.

METHODS

A literature review of the PubMed database was conducted. Articles published between January 1995 and November 2023 concerning the compatibility of intravenous medications in pediatric-dose PN admixtures or with intravenous lipid emulsions only were included. Studies concerning the compatibility/stability of the ingredients of PN admixtures and those concerning unapproved medications were excluded. Based on the methodology used, the quality of the research was assessed.

RESULTS

A total of fifteen studies were explored. Among fifty-five different drug substances assessed in the research reviewed, 56% (31/55) were found to be compatible, 13% (7/55) were assigned as incompatible, and for 31% (17/55), the data were ambiguous. None of the studies demonstrated an "A" grade (very high quality), and the grades "B", "C", and "D" were assigned to four, six, and five studies, respectively. The compatibility data are presented in two tables, the first concerning the simultaneous administration of medications with 2-in-1 PN formulations (without lipids) and the second, with 3-in-1 formulations (with lipids) and lipid emulsions.

CONCLUSIONS

This review presents data on compatibilities between intravenously administered medications and PN mixtures intended for neonates and pediatric patients found in the PubMed database. It should be highlighted, however, that this work has some limitations. The clinical decisions on the simultaneous administration of intravenous medication with PN admixtures should be based not only on this review (including assessment of the quality of evidence) but also on manufacturer data, available electronic databases, and incompatibility data for PN admixtures dedicated to adult patients.

Use of Total Parenteral Nutrition (TPN) as a Vehicle for Drug Delivery

Total Parenteral Nutrition (TPN) is a method of providing nutrients directly into the bloodstream for individuals who are unable to meet their nutritional needs through the normal digestive process or gastrointestinal system. It provides macronutrients and micronutrients in a single container, reducing handling and contamination risks and making it more cost-effective. TPN has the potential to be used as a drug delivery system, with applications in combination therapies, personalized medicine, and integrating advanced technologies. It can enhance drug dosage precision and provide nutritional assistance, potentially reducing hospitalization and improving patient outcomes. However, implementing new applications requires thorough testing and regulatory approval. TPN could be particularly useful in pediatric and geriatric care and could also contribute to global health by combating malnutrition in areas with limited medical resources. Healthcare professionals prepare a sterile solution tailored to each patient's nutritional needs, and administration involves a central venous catheter. However, the simultaneous administration of medications with PN admixtures can result in pharmacological incompatibility, which can impact the stability of the oil-in-water system. The European Society for Clinical Nutrition and Metabolism and the American Society for Parenteral and Enteral Nutrition recommendations advise against including non-nutrient drugs in PN admixtures due to safety concerns. This review focuses on the utilization of Total Parenteral Nutrition (TPN) as a method for delivering drugs. It discusses the benefits and difficulties associated with its commercial application and offers suggestions for future research endeavors.

A Narrative Review: Analysis of Supplemental Parenteral Nutrition in Adults at the End of Life

"End of life" is a stage defined by the existence of an irreversible prognosis that ends with a person's death. One of the aspects of interest regarding end of life focuses on parenteral nutrition, which is usually administered in order to avoid malnutrition and associated complications. However, parenteral nutrition can be adapted to specific circumstances and evolve in its functionality through supplementation with certain nutrients that can have a beneficial effect. This narrative review aims to carry out a situation analysis of the role that could be adopted by supplemental parenteral nutrition in attenuating alterations typical of end of life and potential improvement in quality of life.

Stability and compatibility of parenteral nutrition solutions; a review of influencing factors

Both stability and compatibility of parenteral nutrition solutions (PNS) with drug products are major concerns for clinicians and clinical pharmacists, especially when concurrent administration of PNS with intravenous medications (IVM) is unavoidable. Since the same physicochemical principles apply to both adult's and paediatrics' PNS, concerns about stability and compatibility may still apply to both. However, these concerns are relatively more common in paediatrics and neonatal clinical settings, where limited vascular access can be problematic and the coadministration of PNS and drugs is more common. In neonatal and paediatric populations, there have been few experimental studies and comprehensive evaluations looking at medication compatibility with frequently used PNS. This work is part of a larger research project concerned for compatibility of PNS with commonly used intravenous medication in paediatric and neonates. This paper captures and reviews published data on factors influencing stability and compatibility of parenteral nutrition solutions. This information will help clinicians and clinical pharmacists to understand the principals of the stability and compatibility of PNS, furthermore, it will inform better design of future compatibility studies, as it highlights the complexity of PNS and the multiple factors influencing the stability of PNS, and hence its compatibility with IVM. When preparing, prescribing, and administering the PNS, especially when co-administration with IVM is unavoidable, it is important to take into account the physicochemical properties of the PNS components and IVM as well as administration conditions and environmental factors. These factors should also be considered in the design of the compatibility studies of the PNS with the IVM.

Fluorescent-Dye-Labeled Amino Acids for Real-Time Imaging in Arabidopsis thaliana

Amino acid is the main transport form of reduced nitrogen in plants. To investigate the uptake and source–sink translocation process of plants to help understand their physiological roles and transport mechanisms, we designed and synthesized three fluorescent-dye-labeled amino acids as tools to visualize amino acid transportation in Arabidopsis thaliana; these amino acids consist of amino acids linked to the fluorophore nitrobenzoxadiazole (NBD) with excellent optical properties. Furthermore, we incubated Arabidopsis thaliana with these NBD fluorescent-dye-labeled amino acids for real-time imaging along with fluorescence enhancement for 24 h. The results showed that Arabidopsis thaliana could absorb them directly from the roots to the leaves. Therefore, our fluorescent-dye-labeled amino acids provide a de novo tool and strategy for visualizing amino acid absorption and transportation in plants.

One-chamber and two-chamber parenteral nutrition admixtures for pediatric and adult patients: An evaluation of physico-chemical stability at room and cold temperature

OBJECTIVES

The aim of this study was to evaluate the physico-chemical stability of compounded total parenteral nutrition admixtures through peroxidation assay and ultraviolet-visible spectroscopy, high-performance liquid chromatography analysis, nuclear magnetic resonance spectrometry, pH meter, and dynamic light scattering.

METHODS

The present study considered parenteral nutrition (PN) admixtures for pediatric and adult patients. The admixtures were characterized by a high content of vitamins and trace elements. They were prepared in one- or two-chamber bags in the hospital pharmacy using an automatic compounding system in a sterile room with laminar airflow at different temperature conditions and light exposure. The experiment setup comprised fat emulsions, lipid-free PN solutions, and single-chamber bags before and after adding vitamins and trace elements. The stability at room temperature (+25°C) and cold temperature (+2-8°C) was assessed by various means.

RESULTS

Two-compartment admixtures, single-chamber bags, and all-in-one PN supplemented with vitamins and trace elements are stable up until 35, 9, and 7 d, respectively, when protected from light and stored at +2 to 8°C. Also, the supplemented single-chamber PN was found to be stable up to 48 h when stored at +25°C with light exposure.

CONCLUSIONS

The results obtained will help improve PN management at the compounding center and in hospital wards, because they allow for the extension of the validity time frame provided so far by the different formulations and, therefore, therapy scheduling over several days.

Encapsulation of amino acids in water-in-oil-in-water emulsions stabilized by gum arabic and xanthan gum

In this study, several kinds of amino acids were successfully encapsulated in a W₁/O/W₂ emulsion produced using a two-step emulsification process. Polyglycerol polyricinoleate (PGPR) was used as a hydrophobic emulsifier in the oil phase, while gum arabic (GA) and xanthan gum (XA) were used as an emulsifier and stabilizer in the outer water (W₂) phase, respectively. The stability and encapsulation efficiency of the W₁/O/W₂ emulsions depended on the ratio of W₁/O emulsion to W₂ phase, as well as the concentration of GA and XA within the outer W₂ phase. A W₁/O/W₂ emulsion prepared using 2 % (w/w) GA and 0.3 % (w/w) XA in the W₂ phase exhibited good stability and a high encapsulation efficiency (>80 %) for several amino acids. As the hydrophobicity of amino acids and storage temperature increased, the leakage from the W₁ to W₂ phases increased, which can be attributed to increasing solubility in the oil phase. The encapsulation efficiency of lysine encapsulated in GA-XA-stabilized W₁/O/W₂ double emulsion was over 84 % after 28 days storage at 4 °C. These results indicate that double emulsions may be useful for the encapsulation of amino acids, which may be useful to protect them from their environment and mask bitter flavors.

Underivatized Amino Acid Chromatographic Separation: Optimized Conditions for HPLC-UV Simultaneous Quantification of Isoleucine, Leucine, Lysine, Threonine, Histidine, Valine, Methionine, Phenylalanine, Tryptophan, and Tyrosine in Dietary Supplements

Amino acids (AAs) are considered as the building blocks of life. Unlike nonessential AAs, the human body cannot synthesize essential AAs and should be supplied in food or dietary supplements. The aim of the work is simultaneous HPLC-UV determination of 10 structurally related AAs without pre- or postderivatization in powdered dietary supplements (PDSs). This was challenging, especially because PDS has no standardized procedures for its quality control. HPLC-UV chromatograms of the 10 AAs were recorded using a gradient elution of the mobile phase on a CLC-C18 column at 225 nm. The elution started with 100% of phosphate buffer (pH 7.4, 10 mM) for 10 min; then, the concentration of acetonitrile increased linearly to reach 50% for another 15 min at room temperature. Good separation was achieved within a 25 min run time without pre- or postderivatization. The method was carefully validated according to the ICH guidelines over the linearity range of 100-200, 50-200, 20-150, 50-400, 20-250, 75-175, 50-250, 50-250, 50-300, and 5-100 μg/mL for l-lysine, l-threonine, l-histidine, l-valine, l-methionine, l-isoleucine, l-leucine, l-tyrosine, l-phenylalanine, and l-tryptophan, respectively, with mean recoveries ranges between 98.91 and 100.77. The method was found to be precise, and the relative standard deviation (RSD) was found to be between 0.28 and 1.92 with recoveries between 97.91 and 101.11. The method was found to be robust that resists deliberate changes in pH, flow rate, and mobile-phase percentages. It was successfully applied for the analysis of PDSs. The proposed method could be very useful for the quality control of the 10 structurally related AAs during their synthesis and for testing raw materials and pharmaceutical preparations.

Long time stability of 35 small endogenous biomolecules in dried urine spotted on various surfaces and environmental conditions

Analysis of endogenous biomolecules is an important aspect of many forensic investigations especially with focus on DNA analysis for perpetrator/victim identification and protein analysis for body fluid identification. Recently, small endogenous biomolecules have been used for differentiation of synthetic "fake" urine from authentic urine and might be also useful for biofluid identification. Therefore, the aim of this study was to adapt and optimize a method for analysis of small EBs and to investigate long time stability of 35 small endogenous biomolecules (including acylcarnitines with their isomers and metabolites as well as amino acids with their metabolites) in spotted urine samples. Urine samples were spotted on seven different surfaces (Whatman 903 Protein Saver Cards, cotton swabs, cotton glove, denim, underwear, and smooth and rough flagstone) and stored under six environmental conditions (reference condition, sunlight, LED light, 4 °C, 37 °C, humidity of 95%). At certain time points (d0, d7, d28 and d56) samples were analyzed in triplicates by an optimized extraction and LC-HRMS approach. In addition, the urine marker Tamm-Horsfall-Protein was determined on cotton swabs at the same time points using a commercial lateral flow test. Twenty-one of 35 small endogenous biomolecules were stable on most materials/surfaces and under most storage conditions. Significant lower endogenous biomolecule peak areas were found for rough flagstone and underwear as well as for high humidity storage. Kynurenic acid proved to be photo labile. While high long time stabilities were found for 19 of 28 acylcarnitines, nine acylcarnitines showed aberrant stability patterns without evident structural reason. For Tamm-Horsfall-Protein degradation within 28 days was observed even under reference conditions. The presented study demonstrated the value of sensitive LC-HRMS analysis for small endogenous biomolecules / pattern. However, further studies will be indispensable for unambiguous body fluid identification by small endogenous biomolecules.

Parenteral nutrition compatibility and stability: A comprehensive review

Several guidance documents support best practices across the stages of the parenteral nutrition (PN)-use process to optimize patient safety. The critical step of PN order verification and review by the pharmacist requires a contextual assessment of the compatibility and stability implications of the ordered PN prescription. This article will provide working definitions, describe PN component characteristics, and present a wide-ranging representation of compatibility and stability concerns that need to be considered prior to preparing a PN admixture. This paper has been approved by the ASPEN Board of Directors. This article is protected by copyright. All rights reserved.

Lichtschutz für Lösungen zur parenteralen Ernährung von Säuglingen und Kindern bis zum Alter von 2 Jahren

Das Bundesinstitut für Arzneimittel und Medizinprodukte (BfArM) empfahl im Rote-Hand-Brief vom 02.09.2019: „Während der Verabreichung an Neugeborene und Kinder unter 2 Jahren sollen entsprechend zugelassene Arzneimittel zur parenteralen Ernährung (PE), die Aminosäuren und/oder Fettemulsionen enthalten, vor Licht geschützt werden (Behältnisse und Infusionsbestecke)“.

Ziel dieser Stellungnahme ist es, evidenzbasierte Empfehlungen zum Lichtschutz für Lösungen zu parenteraler und heimparenteraler Ernährung bei Säuglingen und Kindern bis zum Alter von 2 Jahren zu geben.

Der Bundesverband Deutscher Krankenhausapotheker, die Ernährungskommission der Deutschen Gesellschaft für Kinder- und Jugendmedizin, die Ernährungskommission der Österreichischen Gesellschaft für Kinder und Jugendheilkunde und die Arbeitsgemeinschaft Chronisches Darmversagen der Gesellschaft für Pädiatrische Gastroenterologie und Ernährung empfehlen in Übereinstimmung mit den internationalen Empfehlungen zur pädiatrischen parenteralen Ernährung der Fachgesellschaften ESPGHAN, ESPEN, ESPR und CSPEN: 1. Parenterale Nährlösungen, die Fette und/oder Vitamine enthalten, sind während der Applikation durch geeignete Maßnahmen vor Licht zu schützen. 2. Parenterale Nährlösungen, die keine Fette und/oder Vitamine enthalten (z. B. Lösungen mit Aminosäuren, Glucose, Elektrolyten oder Spurenelementen) bedürfen keines speziellen Lichtschutzes. 3. Bei heimparenteraler Ernährung können im Hinblick auf die kindlichen Bedürfnisse normale Spiralleitungen verwendet werden, solange lichtschützende Spiralleitungen nicht verfügbar sind.

Impurity profiling of Compound Amino Acid Injection (6AA) using ion-pair high performance liquid chromatography coupled with corona-charged aerosol detection and high resolution mass spectrometry

The complex industrial production process of amino acids (AAs) leads to the existence of a certain amount of impurities in Compound Amino Acid Injection (6AA). It is difficult to obtain its comprehensive and systematic impurity profile using conventional ultraviolet (UV) detectors due to lack of a suitable chromophore in the structures of AAs and their impurities. In our study, a universal ion-pair high performance liquid chromatography (HPLC) method combined with high resolution mass spectrometer (HRMS) and charged aerosol detection (CAD) was developed to identify and determine the content of impurities in Compound Amino Acid Injection (6AA), respectively. After optimizing the content of trifluoroacetic acid (TFA) and heptafluorobutyric acid (HFBA) in the mobile phase on a C18 AQ column, HPLC-CAD method was developed and nine unknown impurities were detected. These impurities were successfully identified using HPLC coupled with orbitrap mass spectrometry and confirmed with their reference substances. The CAD parameters setting was optimized to improve the sensitivity and linearity of the methods before the developed method was validated. The results of validation reflected that the limit of detection (LOD) was approximately 2 ng (corresponding to approximately 0.02 % of L-isoleucine in injection). Under the optimized power function value (PFV) of CAD, the linear range of each impurity was 1 ∼ 200 μg mL^-1 (the linear range of one of the impurities with higher content was 2 ∼ 400 μg mL^-1) with coefficients of determination (R²) greater than 0.998. The recovery rates for nine impurities were 93.37 % ∼ 110.23 %. This study made full use of the qualitative functions of HRMS and the versatility of CAD, revealing possible impurities in the 6AA injection, which could provide reference for the safety research of it.

Release of amino acids encapsulated in PGPR-stabilized W/O/W emulsions is affected by temperature and hydrophobicity

Double or multiple emulsions have been under study for several decades, due to the possibility of encapsulation and controlled release of various bioactive compounds. This contribution focuses on the decisive parameters for encapsulation and release in double emulsions by considering different amino acids at different environmental conditions. Laser diffraction analysis showed that the double emulsion average droplet size increased from 50 up to 90 µm after 32 days of storage. The emulsions at 4 °C showed a higher increase compared to 37 °C. Dilution in SDS solution revealed that this droplet size increase was due to aggregation rather than coalescence. The results showed that there was no significant change in the entrapped water volume fraction of the double emulsions during 2 weeks of storage. Amino acids were encapsulated within the internal aqueous phase with an efficiency of at least 80%. Regarding the release of the entrapped amino acids, it was found that both the temperature and the hydrophobicity of the amino acid had a significant effect. Fastest release was found at the highest temperature studied (i.e. 37 °C), which was thought to be due to the higher solubility and faster diffusion rate of the amino acid in the oil phase. As hydrophobicity increased, the released amino acid concentration also increased. The pH, on the other hand, did not have a significant effect on the release within the pH range considered (i.e. 7-10). The constant internal water volume fraction, together with the significant effect of temperature and hydrophobicity, indicated that the main release mechanism of amino acids in double emulsions is by direct diffusion from the internal to the external aqueous phase.

Investigation of tryptophan-related yellowing in parenteral amino acid solution: Development of a stability-indicating method and assessment of degradation products in pharmaceutical formulations

Parenteral amino acid solutions containing tryptophan tend to develop a yellow colouration upon storage. Hence, the aim of the present study was to find out whether tryptophan degradation products are the reason for the yellowing. The degree of discolouration and tryptophan degradation was examined by visual examination and UV/Vis measurements with respect to oxygen presence, pH value, and duration of steam sterilization. LC-UV analyses of autoclaved tryptophan solutions indicated eight degradation products, namely R,R/R,S 2-amino-3-(oxoindolin-3-yl)propanoic acid, R,R/R,S 2-amino-3-hydroxy-2-oxoindolin-3-yl)propanoic acids, cis/trans 3a-hydroxy-1,2,3,3a,8,8a-hexahydropyrrolo[2,3-b]indole-2-carboxylic acid, N´-formylkynurenine, and kynurenine. The proposed degradation products were confirmed by spiking of synthesized degradation products and LC-UV/MS analyses. The LC-UV analysis method was optimized and validated according to the ICH guideline Q2 (R1). Tryptophan stability in commercially available parenteral amino acid formulations was evaluated over a storing period of 12 months in two common types of primary packaging after autoclave procedure.

Development of a Stability Indicating Method for Simultaneous Analysis of Five Water-Soluble Vitamins by Liquid Chromatography

Background

Water-soluble vitamins are often included simultaneously in pharmaceutical formulations as food complements or in parenteral nutrition mixtures. Given their sensitivity to heat, light or pH variations, it is important to study their stability using validated stability indicating methods. We thus aimed to validate a liquid chromatography (LC) stability-indicating method for the simultaneous quantification of 5 water-soluble vitamins.

Methods

We analyzed four water-soluble B vitamins (nicotinamide, pyridoxine, folic acid, cyanocobalamin) and ascorbic acid using a LC method with diode array detector. They were separated on a C18 stationary phase under gradient elution of solvent A [0.2 % of metaphosphoric acid in water and acetonitrile 98:2] and solvent B (100 % acetonitrile). All vitamins were subjected to forced degradation conditions and we showed that the obtained degradation products didn’t interfere with the vitamins.

Results

The method allows the separation of the 5 water-soluble vitamins in a 30 minute run without any interference from the breakdown products obtained with acid/alkaline solutions, hydrogen peroxide, temperature and light. It meets all the qualitative and quantitative criteria for validation with an acceptable accuracy and good linearity.

Conclusions

This stability-indicating method can be used for carrying out stability studies of water-soluble vitamins in pharmaceutical preparations.

Do carnitine and extra trace elements change stability of paediatric parenteral nutrition admixtures?

INTRODUCTION

High concentrations of trace elements (TE), in particular zinc and selenium, along with carnitine, are often added to parenteral admixtures in paediatric patients on long-term Parenteral Nutrition (PN). We aim to evaluate whether lipid droplet diameters of these admixtures maintain the recommended range of 0.4-1.0 μm.

MATERIALS AND METHODS

Stability studies were carried out on six parenteral admixtures with carnitine, trace elements and electrolytes added in different amounts. Each admixture was formulated with five different lipid emulsions with or without fish oil. Analyses were performed at time 0 (t = 0) and 24, 48, 72, 96 (t = 96) hours after compounding. Droplet diameters were determined by Light Scattering-Reverse Fourier Optics Technique. Samples, stored at 4 °C, were triple tested for a total of 450 analyses. Regression analyses were performed using panel-data techniques.

RESULTS

During the 4 days, lipid droplet diameters were in the expected range of 0.4-1.0 μm regardless of trace element and carnitine amounts in all admixtures apart from those containing fish-oil based emulsions and calcium concentrations equal to 4.5 mmol/L. In these latter admixtures, 12% of droplet diameters were larger than 1.0 μm and 2% exceeded 5.0 μm immediately after compounding.

CONCLUSION

Carnitine and high concentrations of trace elements do not affect PN admixtures stability and can be safely infused in long-term home-PN paediatric patients and prematures. Only high calcium concentrations in compresence with fish oil based lipid emulsions seem to change PN stability.

Quantitative analysis of amino acids in human and bovine colostrum milk samples through iTRAQ labeling

BACKGROUND

The types and quantity of proteins vary widely between bovine and human milk, with corresponding differences in free and hydrolytic amino acids. In this study, the free and hydrolytic amino acids of bovine and human colostrum were for the first time qualitatively and quantitatively determined using isobaric tags for relative and absolute quantification technology combined with liquid chromatography tandem mass spectrometry detection.

RESULTS

Total free amino acid content was 0.32 g L^-1 and 0.63 g L^-1 in bovine and human colostrum respectively, with free amino acid content in human colostrum twice that of bovine colostrum. However, total hydrolytic amino acid content was 4.2 g L^-1 and 2.2 g L^-1 in bovine and human colostrum respectively. We found that the hydrolytic amino acid content in bovine colostrum was higher than that in human colostrum; however, the amount of free amino acids and the overall amino acid content in human colostrum were respectively substantially higher and more varied than in bovine colostrum.

CONCLUSION

Our findings revealed differences between bovine and human colostrum, with these data providing the basis for further research into amino acid metabolomics and infant formula. © 2018 Society of Chemical Industry.