A versatile, quantitative analytical method for pharmaceutical relevant lipids in drug delivery systems

Detection of aldehydes from degradation of lipid nanoparticle formulations using a hierarchically-organized nanopore electrochemical biosensor

Degradation of ionizable lipids in mRNA-based vaccines was recently found to deactivate the payload, demanding rigorous monitoring of impurities in lipid nanoparticle (LNP) formulations. However, parallel screening for lipid degradation in customized delivery systems for next-generation therapeutics maintains a challenging and unsolved problem. Here, we describe a nanopore electrochemical sensor to detect ppb-levels of aldehydes arising from lipid degradation in LNP formulations that can be deployed in massively parallel fashion. Specifically, we combine nanopore electrodes with a block copolymer (BCP) membrane capable of hydrophobic gating of analyte transport between the bulk solution and the nanopore volume. By incorporating aldehyde dehydrogenase (ALDH), enzymatic oxidation of aldehydes generates NADH to enable ultrasensitive voltammetric detection with limits-of-detection (LOD) down to 1.2 ppb. Sensor utility was demonstrated by detecting degradation of N-oxidized SM-102, the ionizable lipid in Moderna's SpikeVax™ vaccine, in mRNA-1273 LNP formulation. This work should be of significant use in the pharmaceutical industry, paving the way for automated on-line quality assessments of next-generation therapeutics.

Phospholipidomics in Clinical Trials for Brain Disorders: Advancing our Understanding and Therapeutic Potentials

Phospholipidomics is a specialized branch of lipidomics that focuses on the characterization and quantification of phospholipids. By using sensitive analytical techniques, phospholipidomics enables researchers to better understand the metabolism and activities of phospholipids in brain disorders such as Alzheimer's and Parkinson's diseases. In the brain, identifying specific phospholipid biomarkers can offer valuable insights into the underlying molecular features and biochemistry of these diseases through a variety of sensitive analytical techniques. Phospholipidomics has emerged as a promising tool in clinical studies, with immense potential to advance our knowledge of neurological diseases and enhance diagnosis and treatment options for patients. In the present review paper, we discussed numerous applications of phospholipidomics tools in clinical studies, with a particular focus on the neurological field. By exploring phospholipids' functions in neurological diseases and the potential of phospholipidomics in clinical research, we provided valuable insights that could aid researchers and clinicians in harnessing the full prospective of this innovative practice and improve patient outcomes by providing more potent treatments for neurological diseases.

The Chemical Reactivity of Membrane Lipids

It is well-known that aqueous dispersions of phospholipids spontaneously assemble into bilayer structures. These structures have numerous applications across chemistry and materials science and form the fundamental structural unit of the biological membrane. The particular environment of the lipid bilayer, with a water-poor low dielectric core surrounded by a more polar and better hydrated interfacial region, gives the membrane particular biophysical and physicochemical properties and presents a unique environment for chemical reactions to occur. Many different types of molecule spanning a range of sizes, from dissolved gases through small organics to proteins, are able to interact with membranes and promote chemical changes to lipids that subsequently affect the physicochemical properties of the bilayer. This Review describes the chemical reactivity exhibited by lipids in their membrane form, with an emphasis on conditions where the lipids are well hydrated in the form of bilayers. Key topics include the following: lytic reactions of glyceryl esters, including hydrolysis, aminolysis, and transesterification; oxidation reactions of alkenes in unsaturated fatty acids and sterols, including autoxidation and oxidation by singlet oxygen; reactivity of headgroups, particularly with reactive carbonyl species; and E/Z isomerization of alkenes. The consequences of reactivity for biological activity and biophysical properties are also discussed.

Monitoring stability indicating impurities and aldehyde content in lipid nanoparticle raw material and formulated drugs

Lipid nanoparticles (LNPs) are designed to protect and transport sensitive payloads or active pharmaceutical ingredients as part of new therapeutic modalities. As a multi-component particle, a high degree of quality control is necessary to ensure raw materials are free of critical impurities that could adversely impact the drug product. In this study, we demonstrate a reversed phase liquid chromatography method hyphenated with a single quadrupole mass spectrometer (RPLC-MS) as an alternative platform to methods that incorporate evaporative light scattering or charged aerosol detectors in the detection and quantitation of critical impurities associated with LNPs. The proposed RPLC-MS method offers an increase of up to 2 orders of magnitude in dynamic range and 3 orders of magnitude in sensitivity in the analysis of impurities associated with LNPs compared to conventional detectors. Access to complementary mass data enabled the detection and identification of stability indicating impurities as part of stress studies carried out on an ionizable lipid. In addition to confirmation of peak identity, complementary mass data was also used to assess residual aldehydes in raw material and formulated LNPs in accordance with regulatory guidance. Following derivatization using 2,4-dinitrophenylhydrazine, aldehyde content in the ionizable lipid raw material was determined to exceed the reporting threshold of 0.05% in 30% of the test cases. The experimental findings observed in this study demonstrate the utility of the proposed RPLC-MS method in the identification and monitoring of stability-indicating attributes associated with LNPs as part of current Good Manufacturing Practices for improved consumer safety in drug products.

Magnetic iron oxide nanoparticles@lecithin/poly (l-lactic acid) microspheres for targeted drug release in cancer therapy

The use of targeted chemotherapy is a promising solution to mitigate the side effects and dosage of drugs. This research focuses on the development of magnetic microspheres (MMS) based drug carriers for targeted chemotherapy, formulated with iron oxide nanoparticles (Fe3O4 NPs) and poly (l-lactic acid) (PLA) loaded with the antibiotic drug Ciprofloxacin (CIF). In this study, Fe3O4 NPs were synthesized using pomegranate peel extract as a natural reducing and stabilizing agent. The double emulsification method (W1/O/W2) was employed to produce Fe3O4@LEC-CIF-PLA-MMS, which were characterized using various spectral and microscopic techniques. The drug encapsulation efficiency for Fe3O4@LEC-CIF-PLA-MMS was found to be 80.7 %. The in vitro drug release of CIF from Fe3O4@LEC-CIF-PLA-MMS induced by H2O2 and GSH- stimuli was found to be 87.55 % and 82.32 %, respectively in acidic pH 4.5. Notably, the magnetically triggered drug release behaviour of Fe3O4@LEC-CIF-PLA-MMS (93.56 %) was assessed in acidic pH environment upon exposure to low-frequency alternating magnetic field (LF-AMF). Fe3O4@LEC-CIF-PLA-MMS demonstrated significantly enhanced in vitro cytotoxicity (IC50 = 0.8 ± 0.03 μg/mL) against the HeLa-S3 cancer cell lines. Nevertheless, these research findings highlight the potential of Fe3O4@LEC-CIF-PLA-MMS for further development as a chemotherapeutic agent and hold promise for the future of targeted cancer treatment.

Liposomes characterization for market approval as pharmaceutical products: Analytical methods, guidelines and standardized protocols

Liposomes are nano-sized lipid-based vesicles widely studied for their drug delivery capabilities. Compared to standard carries they exhibit better properties such as improved site-targeting and drug release, protection of drugs from degradation and clearance, and lower toxic side effects. At present, scientific literature is rich of studies regarding liposomes-based systems, while 14 types of liposomal products have been authorized to the market by EMA and FDA and many others have been approved by national agencies. Although the interest in nanodevices and nanomedicine has steadily increased in the last two decades the development of documentation regulating and standardizing all the phases of their development and quality control still suffers from major inadequacy due to the intrinsic complexity of nano-systems characterization. Many generic documents (Type 1) discussing guidelines for the study of nano-systems (lipidic and not) have been proposed while there is a lack of robust and standardized methods (Type 2 documents). As a result, a widespread of different techniques, approaches and methodologies are being used, generating results of variable quality and hard to compare with each other. Additionally, such documents are often subject to updates and rewriting further complicating the topic. Within this context the aim of this work is focused on bridging the gap in liposome characterization: the most recent standardized methodologies suitable for liposomes characterization are here reported (with the corresponding Type 2 documents) and revised in a short and pragmatical way focused on providing the reader with a practical background of the state of the art. In particular, this paper will put the accent on the methodologies developed to evaluate the main critical quality attributes (CQAs) necessary for liposomes market approval.

High-Performance Liquid Chromatography Coupled with Tandem Mass Spectrometry Method for the Identification and Quantification of Lipids in Liposomes

Liposomes are spherical, closed vesicles consisting of at least one lipid bilayer with a water chamber and are widely used to encapsulate bioactive molecules. Lipid membranes, composed of different types of lipids or lipophilic components, determine whether liposomes can achieve the desired purpose and determine the overall quality of liposomes. Thus, the quantification of lipid components and encapsulated molecules is essential to characterize and control the quality of liposomes. Moreover, multicomponent simultaneous determination is the preferred method for lipid component analysis in liposomes. Therefore, the present work describes an analytical methodology for the simultaneous determination of commonly used lipids in liposome formulations, using h igh-performance liquid chromatography coupled with a tandem mass spectrometry (MS) detector (HPLC-MS/MS). HPLC-MS/MS consists of a rapid and highly efficient chromatographic separation of the liposomal components with a C18 column and the subsequent detection of the ingredients through an MS detector, along with an accurate mass fragmentation pattern. The analytical process mainly includes lipid extraction, solution preparation, the optimization of chromatographic conditions, and method validation. We hope this analytical methodology is valuable and efficient and can be applied to the analysis of multiple types of lipids in liposomes, such as raw material quality analysis, formulation study, overall quality control, etc.

Challenges and emerging trends in liquid chromatography-based analyses of mRNA pharmaceuticals

Lipid encapsulated messenger RNA (LNP mRNA) has garnered a significant amount of interest from the pharmaceutical industry and general public alike. This attention has been catalyzed by the clinical success of LNP mRNA for SARS-CoV-2 vaccination as well as future promises that might be fulfilled by the biotechnology pipeline, such as the in vivo delivery of a CRISPR/Cas9 complex that can edit patient cells to reduce levels of low-density lipoprotein. LNP mRNAs are comprised of various chemically diverse molecules brought together in a sophisticated intermolecular complex. This can make it challenging to achieve thorough analytical characterization. Nevertheless, liquid chromatography is becoming an increasingly relied upon technique for LNP mRNA analyses. Although there have been significant advances in all types of LNP mRNA analyses, this review focuses on recent developments and the possibilities of applying anion exchange (AEX) and ion pairing reversed phase (IP-RP) liquid chromatography for intact mRNAs as well as techniques for oligo mapping analysis, 5' endcap testing and lipid compositional assays.

A rapid and quantitative reversed-phase HPLC-DAD/ELSD method for lipids involved in nanoparticle formulations

Lipid nanoparticles (LNPs) have shown great success as drug delivery systems, especially for mRNA vaccines, as those developed during the Covid-19 pandemics. Lipid analysis is critical to monitor the formulation process and control the quality of LNPs. The present study is focused on the development and validation of a high-performance liquid chromatography – diode array detector –evaporative light scattering detector (HPLC-DAD/ELSD) based method for the simultaneous quantification of 7 lipids, illustrating the main components of LNPs: ionizable lipids, the neutral co-lipid cholesterol, phospholipids, hydrophilic polymer-lipids for colloidal stability (e.g., a PEGylated lipid). In particular, this study focuses on two innovative synthetic lipids: a switchable cationic lipid (CSL3) which has demonstrated in vitro and in vivo siRNA transfection abilities, and the palmitic acid-grafted-poly(ethyloxazoline)₅₀₀₀ (PolyEtOx), used as an alternative polymer to address allergic reactions attributed to PEGylated lipids. The HPLC separation was achieved on a Poroshell C18 column at 50 °C using a step gradient of a mobile phase composed of water/methanol mixtures with 0.1% (v/v) trifluoroacetic acid (TFA). This method was validated following ICH Q2(R1) & (R2) guidelines in terms of linearity (R² ≥ 0.997), precision (relative standard deviation on peak areas < 5% for intermediate repeatability), accuracy (recoveries between 92.9% and 108.5%), and sensitivity. Indeed, low detection and quantitation limits were determined (between 0.02 and 0.04 µg and between 0.04 and 0.10 µg, respectively). Due to its high selectivity, this method allowed the analysis of lipid degradation products produced through degradation studies in basic, acidic, and oxidative conditions. Moreover, the method was successfully applied to the analysis of several liposome formulations at two key steps of the development process. Consequently, the reported HPLC method offers fast, versatile, selective and quantitative analysis of lipids, essential for development optimization, chemical characterization, and stability testing of LNP formulations.

Simultaneous Chromatographic Quantitation of Drug Substance and Excipients in Nanoformulations Using a Combination of Evaporative Light Scattering and Absorbance Detectors

Nanomedicines including lipid- and polymer-based nanoparticles and polymer-drug conjugates enable targeted drug delivery for the treatment of numerous diseases. Quantitative analysis of components in nanomedicines is routinely performed to characterize the products to ensure quality and property consistency but has been mainly focused on the active pharmaceutical ingredients (APIs) in academic publications. It has been increasingly recognized that excipients in nanomedicines are critical in determining the product quality, stability, consistency, and safety. APIs are often analyzed by high-performance liquid chromatography (HPLC), and it would be convenient if the same method can be applied to excipients to robustly quantify all components in nanomedicines. Here, we report the development of a HPLC method that combined an evaporative light scattering (ELS) detector with an UV-vis detector to simultaneously analyze drugs and excipients in nanomedicines. This method was tested on diverse nanodrug delivery systems, including a niosomal nanoparticle encapsulating a phytotherapeutic, a liposome encapsulating an immune boosting agent, and a PEGylated peptide. This method can be utilized for a variety of applications, such as monitoring drug loading, studying drug release, and storage stability. The information obtained from the analyses is of importance for nanomedicine formulation development.

Analysis of verteporfin liposomal formulations for phospholipids and phospholipid degradation products by liquid chromatography-mass spectrometry (LC-MS)

Lipid composition and lipid degradation are critical to the stability of liposomal formulations which can impact the safety and efficacy of the drug. Herein we developed and validated an ultrahigh performance liquid chromatography coupled with quadrupole time of flight mass spectrometry (UPLC-QTOF-MS) method for determining phospholipid composition and phospholipid degradation products in a verteporfin liposomal formulation (Visudyne). The high mass accuracy (<5 ppm) of the QTOF method coupled with database searching (SimLipid) and comparison with known standards accurately identified and quantified the phospholipid compositions and lipid degradation products. The analysis of Visudyne indicated that more than 50% (w/w) of the total phospholipids are composed of phosphatidylcholine (PC) 14:0-14:0 and major phosphatidylglycerol (PG) species found are PG 16:0-18:2, PG 16:0-18:1, PG 18:0-18:2, and PG 18:0-18:1. The LC-MS method developed is capable of separating structural isomers such as PG 18:1-18:1 versus PG 18:0-18:2 and the separation of PG stereoisomers, such as PG 18:1-18:1 cis and PG 18:1-18:1 trans. The major lipid degradation products in Visudyne includes lysophosphatidylcholine and a few saturated and unsaturated lysophosphatidylglycerols, and free fatty acids (FFA). Each degradation product is less than 1% of the total phospholipids (w/w). In addition, the lipid profiles of naturally sourced egg PG from six different vendors were compared with the PG composition in Visudyne. Differences in lipid composition in egg PGs from different vendors were observed and the PG composition in Visudyne is matched with the lipid profile of the some of the egg PGs from different vendors. Drug developers can utilize this method to assess raw materials and lipid-based drug product quality and regulatory scientists can monitor the quality of the drug available in the market using this validated method.

Analytical characterization of liposomes and other lipid nanoparticles for drug delivery

Lipid nanoparticles, especially liposomes and lipid/nucleic acid complexed nanoparticles have shown great success in the pharmaceutical industry. Their success is attributed to stable drug loading, extended pharmacokinetics, reduced off-target side effects, and enhanced delivery efficiency to disease targets with formidable blood-brain or plasma membrane barriers. Therefore, they offer promising formulation options for drugs limited by low therapeutic indexes in traditional dosage forms and current "undruggable" targets. Recent development of siRNA, antisense oligonucleotide, or the CRISPR complex-loaded lipid nanoparticles and liposomal vaccines also shed light on their potential in enabling versatile formulation platforms for new pharmaceutical modalities. Analytical characterization of these nanoparticles is critical to drug design, formulation development, understanding in vivo performance, as well as quality control. The multi-lipid excipients, unique core-bilayer structure, and nanoscale size all underscore their complicated critical quality attributes, including lipid species, drug encapsulation efficiency, nanoparticle characteristics, product stability, and drug release. To address these challenges and facilitate future applications of lipid nanoparticles in drug development, we summarize available analytical approaches for physicochemical characterizations of lipid nanoparticle-based pharmaceutical modalities. Furthermore, we compare advantages and challenges of different techniques, and highlight the promise of new strategies for automated high-throughput screening and future development.

ROS-Responsive Chitosan Coated Magnetic Iron Oxide Nanoparticles as Potential Vehicles for Targeted Drug Delivery in Cancer Therapy

Background and Objective

Cancer cells accumulate high concentrations of reactive oxygen species as a result of their faster and uninhibited metabolic activity. Cancer chemotherapeutic agents release an excess of severe adverse reactions as a result of targeting normal cells. This demands an improvement in targeted drug-delivery systems to selectively discharge anticancer drugs in the vicinity of such highly metabolically and mitotically active cells.

Materials and Methods

Here, magnetic nanoparticles were synthesized by a traditional co-precipitation technique. Fe₃O₄@OA-CS-5-FLU-NPs were synthesized by an easy and rapid in situ loading method. The proposed Fe₃O₄@OA-CS-5-FLU-NPs were productively prepared as well as characterized by various spectroscopic and microscopic studies.

Results

The targeted drug release profile of the Fe₃O₄@OA-CS-5-FLU-NPs was studied in the presence of ROS including H₂O₂ and pH induction. The released product, Fe₃O₄@OA-CS-5-FLU-NP, exhibited desirable levels of cytotoxicity and demonstrated morphological changes and inhibition of colony formation for A549 and HeLa S3 cancer cells. The IC50 values at 24 hours were 12.9 and 23 μg/mL, respectively.

Conclusion

In summary, results from the MTT assay, fluorescence staining as well as colony formation assays, revealed that the Fe₃O₄@OA-CS-5-FLU-NPs were active and safe for anticancer biomedical applications. In summary, the present investigation provides a powerful nanostructured based system for improved cancer theranostics that should be further studied.

Development and validation of a novel UPLC-ELSD method for the assessment of lipid composition of nanomedicine formulation

Lipid nanocarriers incorporating glycerides, polyethylene glycol (PEG)-stearates and phospholipids have attracted great attention for in vivo diagnostic, in vivo imaging, activated or non-activated targeted drug delivery. For quality control purposes, the development of appropriate methods for the quantification of their lipid components is needed. In the present study, we developed an analytical method for lipid quantification in formulated nanoparticles. PEG-stearates and glycerides were analyzed in a single run by RP-UPLC-ELSD using a two-step gradient elution program, while the analysis of phospholipids was accomplished by HILIC-UPLC-ELSD after isolation using an SPE silica column. Using both isolated compounds and commercial lipid standards, calibration curves were produced using second-order polynomials to attain the quantitative evaluation of each lipid excipient. Relative standard deviation of all analytes was between 0.9% and 5.3% for intra-day precision and recovery ranged from 83.5% to 112.2%. The presented method was successfully implemented to study the manufacturing process and stability of the formulated lipid excipients during long-term storage and accelerated conditions. The formulation lipid yield was determined and found equal to 82.5%.

Design and development of a biorelevant simulated human lung fluid

Biorelevant fluids are required to enable meaningful in vitro experimental determinations of the biopharmaceutical properties of inhaled medicines, e.g. drug solubility, particle dissolution, cellular uptake. Our aim was to develop a biorelevant simulated lung fluid (SLF) with a well-defined composition and evidence-based directions for use. The SLF contained dipalmitoylphosphotidylcholine, dipalmitoylphosphatidylglycerol, cholesterol, albumin, IgG, transferrin and antioxidants. Freshly made SLF had pH 7.2, viscosity 1.138 × 10⁻³ Pa s, conductivity 14.5 mS/m, surface tension 54.9 mN/m and density 0.999 g/cm³. Colour, surface tension and conductivity were the most sensitive indicators of product deterioration. The simulant was stable for 24 h and 48 h at 37 °C and 21 °C, respectively, (in-use stability) and for 14 days when stored in a refrigerator (storage stability). To extend stability, the SLF was vacuum freeze-dried in batches to produce lyophilised powder that can be reconstituted readily when needed at the point of use. In conclusion, we have reported the composition and manufacture of a biorelevant, synthetic SLF, provided a detailed physico-chemical characterisation and recommendations for how to store and use a product that can be used to generate experimental data to provide inputs to computational models that predict drug bioavailability in the lungs.

Zeta potential: a case study of cationic, anionic, and neutral liposomes

Zeta potential is often used to approximate a nanoparticle's surface charge, i.e., cationic, anionic, or neutral character, and has become a standard characterization technique to evaluate nanoparticle surfaces. While useful, zeta potential values provide only very general conclusions about surface charge character. Without a thorough understanding of the measurement parameters and limitations of the technique, these values can become meaningless. This case study attempts to explore the sensitivity of zeta potential measurement using specifically formulated cationic, anionic, and neutral liposomes. This study examines zeta potential dependence on pH and ionic strength, resolving power, and highlights the sensitivity of zeta potential to charged liposomes. Liposomes were prepared with cholesterol, 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), and varying amounts of 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) or 1,2-dioleoyl-sn-glycero-3-phospho-L-serine (DOPS). A strong linear relationship was noted between zeta potential values and the mole percentage of charged lipids within a liposome (e.g., cationic DOTAP or anionic DOPS). This finding could be used to formulate similar liposomes to a specific zeta potential, potentially of importance for systems sensitive to highly charged species. In addition, cationic and anionic liposomes were titrated with up to two mole percent of the neutral lipid 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] (lipid-PEG; LP). Very small amounts of the lipid-PEG (<0.2 mol%) were found to impart stability to the DOTAP- and DOPS-containing liposomes without significantly affecting other physicochemical properties of the formulation, providing a simple approach to making stable liposomes with cationic and anionic surface charge.