Real-time prediction of dissolution profiles of coated oral dosage forms.

Optical coherence tomography (OCT) has emerged as an in-line monitoring technique for pharmaceutical coating processes based on a representative number of samples. In this study, an approach was developed to correlate the coating thickness measured in-line via OCT with the resultant tablet dissolution profile. This strategy enables prediction of the dissolution profile of coated oral dosage forms for each individual state of the coating process in real-time. Correlation models were developed for a tablet pan coating process and for a pellet fluid-bed coating process. The feasibility of the correlation models was tested using different process parameters and types of coating formulations. This work demonstrated that using the OCT data to predict dissolution could possibly form a unique way of assuring drug product quality and establishing a control strategy within the real-time release testing (RTRT) concept.

Formulation strategies, preparation methods, and devices for pulmonary delivery of biologics.

Biological products, including vaccines, blood components, and recombinant therapeutic proteins, are derived from natural sources such as humans, animals, or microorganisms and are typically produced using advanced biotechnological methods. The success of biologics, particularly monoclonal antibodies, can be attributed to their favorable safety profiles and target specificity. However, their large molecular size presents significant challenges in drug delivery, particularly in overcoming biological barriers. Pulmonary delivery has emerged as a promising route for administering biologics, offering non-invasive delivery with rapid absorption, high systemic bioavailability, and avoidance of first-pass metabolism. This review first details the anatomy and physiological barriers of the respiratory tract and the associated challenges of pulmonary drug delivery (PDD). It further discusses innovations in PDD, the impact of particle size on drug deposition, and the use of secondary particles, such as nanoparticles, to enhance bioavailability and targeting. The review also explains various devices used for PDD, including dry powder inhalers (DPIs) and nebulizers, highlighting their advantages and limitations in delivering biologics. The role of excipients in improving the stability and performance of inhalation products is also addressed. Since dry powders are considered the suitable format for delivering biomolecules, particular emphasis is placed on the excipients used in DPI development. The final section of the article reviews and compares various dry powder manufacturing methods, clarifying their clinical relevance and potential for future applications in the field of inhalable drug formulation.

Lipid-based particle engineering via spray-drying for targeted delivery of antibiotics to the lung.

Pulmonary delivery of antibiotics for the treatment of tuberculosis provides several benefits compared to conventional oral and parenteral administration. API-loaded particles delivered directly to alveolar macrophages, where Mycobacterium tuberculosis resides, can reduce the required dose and decrease the severe side effects of conventional treatment. In this work, lipid-microparticles loaded with rifampicin were engineered via spray-drying to be administered as a carrier-free dry powder for inhalation. Although, it is well-known that spray-drying of lipid-based excipients is strongly limited, a completely lipid-based formulation using diglycerol full ester of behenic acid was produced. The solid state of the lipid, providing high melting temperature, absence of polymorphism and monophasic crystallization, led to high yield of spray-dried particles (83%). Inhalable particles of mass median aerodynamic diameter of 2.36 µm, median geometric size of 2.05 µm, and negative surface (-50.03 mV) were engineered. Such attributes were defined for deep lung deposition and targeted delivery of antibiotics to alveolar macrophages. Superior aerodynamic performance as carrier-free DPI was associated to a high fine particle fraction of 79.5 %. No in vitro cytotoxic effects were found after exposing epithelial cell lines and alveolar macrophages. In vitro uptake of particles into alveolar macrophages indicated the efficiency of their targeted delivery. The use of highly processable and safe lipid-based excipients for particle engineering via spray-drying can extend the availability of materials for functionalized applications for pulmonary delivery.

Mechanically promoted lipid-based filaments via composition tuning for extrusion-based 3D-printing.

Lipid excipients are favorable materials in pharmaceutical formulations owing to their natural, biodegradable, low-toxic and solubility/permeability enhancing properties. The application of these materials with advanced manufacturing platforms, particularly filament-based 3D-printing, is attractive for personalized manufacturing of thermolabile drugs. However, the filament's weak mechanical properties limit their full potential. In this study, highly flexible filaments were extruded using PG6-C16P, a lipid-based excipient belonging to the group of polyglycerol esters of fatty acids (PGFAs), based on tuning the ratio between its major and minor composition fractions. Increasing the percentage of the minor fractions in the system was found to enhance the relevant mechanical filament properties by 50-fold, guaranteeing a flawless 3D-printability. Applying a novel liquid feeding approach further improved the mechanical filament properties at lower percentage of minor fractions, whilst circumventing the issues associated with the standard extrusion approach such as low throughput. Upon drug incorporation, the filaments retained high mechanical properties with a controlled drug release pattern. This work demonstrates PG6-C16 P as an advanced lipid-based material and a competitive printing excipient that can empower filament-based 3D-printing.

Premexotac: Machine learning bitterants predictor for advancing pharmaceutical development.

Bitter taste receptors were recently found to be involved in numerous physiological and pathological conditions other than taste and are suggested as potential drug targets. In vivo and in vitro techniques for screening bitterants as ligands come with economical, time and ethic challenges. Therefore, in silico tools can represent a valuable alternative due to their practicality. Yet, the main challenge of already established ligand-based (LB) classifiers is the low number of experimentally confirmed bitterants and non-bitterants. Premexotac models were constructed as a LB bitterants screener, exploring novel combinations of feature extraction, feature selection and learning algorithms as a contrast with the already available screeners. Premexotac came among the top performers, exhibiting a F-1 score up to 81% on external validation. Premexotac identified as well insights on physicochemical and topological descriptors important for bitter prediction. Among the key insights, important molecular substructures from Extended Connectivity Fingerprints for bitterness classification were identified. Also, the importance of a selection of physicochemical/topological descriptors was ranked using mutual information and it was found that descriptors related to the ramification of the molecular structure and molecular weight came at the top of the ranking. The remaining challenges for improving performance were discussed and stated, widening the LB bitterness prediction outlook.

A Package of Established Analytical Tools to Investigate the Solid-State Alteration of Lipid-Based Excipients.

Lipid-based excipients (LBEs) are low-toxic, biocompatible, and natural-based, and their application supports the sustainability of pharmaceutical manufacturing. However, the major challenge is their unstable solid-state, affecting the stability of the pharmaceutical product. Critical physical properties of lipids for their processing-such as melt temperature and viscosity, rheology, etc.-are related to their molecular structure and their crystallinity. Additives, as well as thermal and mechanical stress involved in the manufacturing process, affect the solid-state of lipids and thus the performance of pharmaceutical products thereof. Therefore, understanding the alteration in the solid-state is crucial. In this work, the combination of powder x-ray diffraction and differential scanning calorimetry (DSC) is introduced as the gold standard for the characterization of lipids' solid state. X-ray diffraction is the most efficient method to screen polymorphism and crystal growth. The polymorphic arrangement and the lamella length are characterized in the wide- and small-angle regions of x-ray diffraction, respectively. The small-angle x-ray scattering (SAXS) region can be further used to investigate crystal growth. Phase transition and separation can be indicated. DSC is used to screen the thermal behavior of lipids, estimate the miscibility of additives and/or active pharmaceutical ingredients (API) in the lipid matrix, and provide phase diagrams. Four case studies are presented in which LBEs are either used as a coating material or as an encapsulation matrix to provide lipid-coated multiparticulate systems and lipid nanosuspensions, respectively. The lipid solid-state and its potential alteration during storage are investigated and correlated to the alteration in the API release. Qualitative microscopical methods such as polarized light microscopy and scanning electron microscopy are complementary tools to investigate micro-level crystallization. Further analytical methods should be added based on the selected manufacturing process. The structure-function-processability relationship should be understood carefully to design robust and stable lipid-based pharmaceutical products.

Filament-based 3D-printing of placebo dosage forms using brittle lipid-based excipients.

In order to expand the limited portfolio of available polymer-based excipients for fabricating three-dimensional (3D) printed pharmaceutical products, Lipid-based excipients (LBEs) have yet to be thoroughly investigated. The technical obstacle of LBEs application is, however their crystalline nature that renders them very brittle and challenging for processing via 3D-printing. In this work, we evaluated the functionality of LBEs for filament-based 3D-printing of oral dosage forms. Polyglycerol partial ester of palmitic acid and polyethylene glycols monostearate were selected as LBEs, based on their chemical structure, possessing polar groups for providing hydrogen-bonding sites. A fundamental understanding of structure-function relationship was built to screen the critical material attributes relevant for both extrusion and 3D-printing processes. The thermal behavior of lipids, including the degree of their supercooling, was the critical attribute for their processing. The extrudability of materials was improved through different feeding approaches, including the common powder feeding and a devised liquid feeding setup. Liquid feeding was found to be more efficient, allowing the production of filaments with high flexibility and improved printability. Filaments with superior performance were produced using polyglycerol ester of palmitic acid. In-house designed modifications of the utilized 3D-printer were essential for a flawless processing of the filaments.

Going green: Development of a sustainable lipid-based enteric coating formulation for low-dose aspirin multiparticulate systems.

There is a rising awareness of pharmaceutical industry of both patient-centric and sustainable product development. Manufacturing of multiparticulate systems (MPS) with functional coating via solvent-free hot melt coating (HMC) can fulfill both requirements. An innovative lipid-based formulation was developed with the composition of palmitic acid and Grindsted® citrem BC-FS (BC-FS) for enteric coating of acetylsalicylic acid (ASA). The ASA crystals were directly hot melt coated to produce user-friendly low-dose ASA MPS for thromboembolism prophylaxis. Prior to HMC, rational boundaries for the process temperature were defined based on the melting and crystallization behavior of coating blend. Stability of coating in terms of resistance to heat stress and solidstate stability were screened via Fourier-transform infrared spectroscopy and x-ray diffraction. Exposure of coating blend to 100 °C for two hours did not cause any chemical degradation. Crystal growth of palmitic acid and polymorphic transformation in BC-FS were observed after storage under accelerated conditions, however did not significantly affect the ASA release from coating. The developed formulation is a unique solvent-free, lipid-based enteric composition and paves the way for sustainable green pharmaceutical manufacturing.

Lipid-microparticles for pulmonary delivery of active pharmaceutical ingredients: Impact of lipid crystallization on spray-drying processability.

Spray-drying is an extensively used technology for engineering inhalable particles. Important technical hurdles are however experienced when lipid-based excipients (LBEs) are spray-dried. Stickiness, extensive wall deposition, or simply inability to yield a solid product have been associated to the low melting points of LBEs. In this work, solutions containing polyglycerol esters of behenic acid (PGFA-behenates), or other high melting point LBEs, were spray-dried to produce ibuprofen (IBU)-loaded inhalable lipid-microparticles. Prior to spray-drying, rational boundaries for the outlet temperature of the process were defined using LBE-IBU phase diagrams. Despite spray-drying the solutions at outlet temperatures below the boundaries, process performance and yield among LBEs were entirely different. Lipid crystallization into polymorphs or multi-phases negatively impacted the yield (10-47%), associated to liquid fractions unable to recrystallize at the surrounding gas temperature in the spray-dryer. The highest yields (76-82%), ascribed to PGFA-behenates, resulted from monophasic crystallization and absence of polymorphism. Lipid-microparticles, composed of a PGFA-behenate, were characterized by a volume mean diameter of 6.586 µm, tap density of 0.389 g/cm3 and corrugated surface. Application as carrier-free dry powder for inhalation resulted in high emitted fraction (90.9%), median mass aerodynamic diameter of 3.568 µm, fine particle fraction of 45.6% and modified release in simulated lung fluid.

Impact of polysorbate 65 on tripalmitin crystal growth and release stability of hot melt coated multiparticulate systems.

Hydrochlorothiazide (HCT) multiparticulate systems (MPS) were hot melt coated with the binary mixture of tripalmitin (PPP) and polysorbate 65 (PS 65) to gain an immediate release profile. Once, HCT MPS were produced with a constant ratio of PPP/PS 65 (90:10) at three different coating amounts (15, 25, and 60%w/w) and once the PPP/PS 65 ratio was varied on 98:2 and 80:20, by keeping the coating amount at 60%w/w. PS 65 induced the polymorphic transformation of PPP from the α-form to its most stable ß-form right after the hot melt coating (HMC). A release alteration of HCT, either accelerated or decelerated, occurred after the storage under accelerated conditions. The effect of the API core on the lipid lamellar configuration, the thermal behavior of lipid coating, and the effect of PS 65 concentration on the crystal growth of PPP were investigated via X-ray diffraction and DSC. While a low amount of PS 65 was sufficient to promote crystal growth of PPP and resulted in a decelerated release of HCT from the coating, a higher PS 65 concentration favored phase separation of PPP and PS 65 and led to an accelerated release. The increase in PS 65 reinforced the molecular interaction with the lipophilic HCT, reflected in less crystal growth and decelerated release. The knowledge presented in this study supports understanding the instability of binary emulsifier-lipid coating systems, paving the way for developing robust HMC formulations.

Oral inhalation for delivery of proteins and peptides to the lungs.

Oral inhalation is the preferred route for delivery of small molecules to the lungs, because high tissue levels can be achieved shortly after application. Biologics are mainly administered by intravenous injection but inhalation might be beneficial for the treatment of lung diseases (e.g. asthma). This review discusses biological and pharmaceutical challenges for delivery of biologics and describes promising candidates. Insufficient stability of the proteins during aerosolization and the biological environment of the lung are the main obstacles for pulmonary delivery of biologics. Novel nebulizers will improve delivery by inducing less shear stress and administration as dry powder appears suitable for delivery of biologics. Other promising strategies include pegylation and development of antibody fragments, while carrier-encapsulated systems currently play no major role in pulmonary delivery of biologics for lung disease. While development of various biologics has been halted or has shown little effects, AIR DNase, alpha1-proteinase inhibitor, recombinant neuraminidase, and heparin are currently being evaluated in phase III trials. Several biologics are being tested for the treatment of coronavirus disease (COVID)-19, and it is expected that these trials will lead to improvements in pulmonary delivery of biologics.

Impact of Surface Properties of Core Material on the Stability of Hot Melt-Coated Multiparticulate Systems.

Hot melt coating (HMC) of an active pharmaceutical ingredient (API) powder with lipid-based excipients is an innovative method for manufacturing patient-convenient dosage forms. However, drug release instability is still its main industrial challenge. The correlation between the unstable pharmaceutical product performance with the solid-state alteration of lipids is currently well-investigated. The remaining problem is the inconsistent release alteration of different APIs coated with the same lipid after storage, such as faster release in some cases and slower release in others. The interaction between API surface and lipid-based coating and its alteration during storage were investigated in this work. The surface properties of five different APIs and the coating composition of tripalmitin and polysorbate 65 were screened via Washburn and pendant drop methods, respectively. Metformin hydrochloride and hydrochlorothiazide particles were each coated with the coating composition. The water sorption alteration of coated particles and the crystal growth of tripalmitin in the coating after storage were measured via tensiometry and X-ray diffraction. The cleavage work necessary to overcome the adhesion of coating composition on the core surface was calculated for each API. The accelerated release of the polar core (metformin) after storage was correlated with a low cleavage work and a distinctive phase separation. In contrast, a decelerated release of the hydrophobic core (hydrochlorothiazide) was favored by the crystal growth of the lipid-based coating. The gained knowledge can be used to design the product stability during the formulation development.

Bitter taste in silico: A review on virtual ligand screening and characterization methods for TAS2R-bitterant interactions.

The growing pharmaceutical interest in the human bitter taste receptors (hTAS2Rs) has two dimensions; i) evaluation of the bitterness of active pharmaceutical compounds, in order to develop strategies for improving patients' adherence to medication, and ii) application of ligands for extra-cellular hTAS2Rs for potential preventive therapeutic achievements. The result is an increasing demand on robust tools for bitterness assessment and screening the receptor-ligand affinity. In silico tools are useful for aiding experimental-screening, as well as to elucide ligand-receptor interactions. In this review, the ligand-based and structure-based approaches are described as the two main in silico tools for bitter taste analysis. The strengths and weaknesses of each approach are discussed. Both approaches provide key tools for understanding and exploiting bitter taste for human health applications.

Hot Melt Coating of Amorphous Carvedilol.

The use of amorphous drug delivery systems is an attractive approach to improve the bioavailability of low molecular weight drug candidates that suffer from poor aqueous solubility. However, the pharmaceutical performance of many neat amorphous drugs is compromised by their tendency for recrystallization during storage and lumping upon dissolution, which may be improved by the application of coatings on amorphous surfaces. In this study, hot melt coating (HMC) as a solvent-free coating method was utilized to coat amorphous carvedilol (CRV) particles with tripalmitin containing 10% (w/w) and 20% (w/w) of polysorbate 65 (PS65) in a fluid bed coater. Lipid coated amorphous particles were assessed in terms of their physical stability during storage and their drug release during dynamic in vitro lipolysis. The release of CRV during in vitro lipolysis was shown to be mainly dependent on the PS65 concentration in the coating layer, with a PS65 concentration of 20% (w/w) resulting in an immediate release profile. The physical stability of the amorphous CRV core, however, was negatively affected by the lipid coating, resulting in the recrystallization of CRV at the interface between the crystalline lipid layer and the amorphous drug core. Our study demonstrated the feasibility of lipid spray coating of amorphous CRV as a strategy to modify the drug release from amorphous systems but at the same time highlights the importance of surface-mediated processes for the physical stability of the amorphous form.

Novel approach for overcoming the stability challenges of lipid-based excipients. Part 3: Application of polyglycerol esters of fatty acids for the next generation of solid lipid nanoparticles.

Solid lipid nanoparticles (SLN) are an advantageous carrier system for the delivery of lipophilic active pharmaceutical ingredients (APIs). The use of SLN has been limited due to stability issues attributed to the unstable solid state of the lipid matrix. A novel approach for overcoming this problem is the application of polyglycerol esters of fatty acids (PGFAs) as lipid matrices with stable solid state. PG2-C18 full, a PGFA molecule, was used to develop SLN loaded with dexamethasone as a model API. Dexamethasone-loaded SLN were manufactured via melt-emulsification and high pressure homogenization in the dosage form of a lipid nanosuspension. SLN with median particle size of 242.1 ± 12.4 nm, zeta potential of -28.5 ± 7.8 mV, entrapment efficiency of 90.2 ± 0.7% and API released after 24 h of 81.7 ± 0.7%, were produced. Differential Scanning Calorimetry (DSC) and Small and Wide Angle X-Ray Scattering (SWAXS) analysis of the lipid nanosuspension evidenced the crystallization of PG2-C18 full in a monophasic system in α-form and absence of polymorphism and crystallite growth up to 6 months storage at room temperature. This resulted in stable performance of the SLN after storage: absence of particle agglomeration, no API expulsion, and stable release profile. The potential pulmonary administration of SLN was tested by the nebulization capacity of the lipid nanosuspension. Cellular exposures to SLN did not induce cytotoxicity or immune effect on pulmonary cells. The application of PGFAs as safe and stable lipid matrices provide a promising approach for the development of the next generation of SLN.

Novel approach for overcoming the stability challenges of lipid-based excipients. Part 1: Screening of solid-state and physical properties of polyglycerol esters of fatty acids as advanced pharmaceutical excipients.

The major challenge of conventional lipid-based excipients (LBE) for drug delivery is their unstable solid state, affecting the stability of pharmaceutical product. Polyglycerol esters of fatty acids (PGFAs) are oligomeric hydroxyethers of glycerol fully or partially esterified with fatty acids. Tuning the number of polyglycerol moieties, fatty acids chain length and free hydroxyl groups per molecule results in diverse physicochemical properties, e.g. HLB, melting point, and wettability, which makes these molecules attractive candidates as novel LBE for different pharmaceutical applications. In this first part of our studies the solid state of PGFAs and the stability thereof were profiled on molecular, nano, and microstructural level and the resulting properties as LBE. DSC analysis confirmed the single phase system of PGFAs without phase separation. WAXS patterns revealed the absence of polymorphism and the direct crystallization into a stable α-form; without transition to more dense configurations. SAXS patterns exposed the lamellar arrangement. The lamellae stacks were characterized by the crystallite thickness and growth. The nano, microstructure and physicochemical properties of PGFAs remained stable during storage. The stable solid state and the broad functionality of PGFAs offer a novel approach to overcome the challenges faced by conventional LBE for advanced pharmaceutical applications. Examples for such applications are presented in the next parts of this study.

Novel approach for overcoming the stability challenges of lipid-based excipients. Part 2: Application of polyglycerol esters of fatty acids as hot melt coating excipients.

The application of hot melt coating (HMC) as an economic and solvent-free technology is restricted in pharmaceutical development, due to the instable solid-state of HMC excipients resulting in drug release instability. We have previously introduced polyglycerol esters of fatty acids (PGFAs) with stable solid-state (Part 1). In this work we showed a novel application of PGFAs as HMC excipients with stable performance. Three PGFA compounds with a HLB range of 5.1-6.2 were selected for developing immediate-release formulations. The HMC properties were investigated. The viscosity of molten lipids at 100 °C was suitable for atomizing. The DSC data showed the absence of low solidification fractions, thus reduced risk of agglomeration during the coating process. The driving force for crystallization of selected compounds was lower and the heat flow exotherms were broader compared to conventional HMC formulations, indicating a lower energy barrier for nucleation and lower crystallization rate. Lower spray rates and a process temperature close to solidification temperature were desired to provide homogeneous coating. DSC and X-ray diffraction data revealed stable solid state during 6 months storage at 40 °C. API release was directly proportional to HLB and indirectly proportional to crystalline network density and was stable during investigated 3 months. Cytotoxicity was assessed by dehydrogenase activity and no in vitro cytotoxic effect was observed.

In vitro toxicity screening of polyglycerol esters of fatty acids as excipients for pulmonary formulations.

One of the main problems for the development of pulmonary formulations is the low availability of approved excipients. Polyglycerol esters of fatty acids (PGFA) are promising molecules for acting as excipient for formulation development and drug delivery to the lung. However, their biocompatibility in the deep lung has not been studied so far. Main exposed cells include alveolar epithelial cells and alveolar macrophages. Due to the poor water-solubility of PGFAs, the exposure of alveolar macrophages is expected to be much higher than that of epithelial cells. In this study, two PGFAs and their mixture were tested regarding cytotoxicity to epithelial cells and cytotoxicity and functional impairment of macrophages. Cytotoxicity was assessed by dehydrogenase activity and lactate dehydrogenase release. Lysosome function, phospholipid accumulation, phagocytosis, nitric oxide production, and cytokine release were used to evaluate macrophage function. Cytotoxicity was increased with the increased polarity of PGFA molecules. At concentrations above 1 mg/ml accumulation in lysosomes, impairment of phagocytosis, secretion of nitric oxide, and increased release of cytokines were noted. The investigated PGFAs in concentrations up to 1 mg/ml can be considered as uncritical and are promising for advanced pulmonary delivery of high powder doses and drug targeting to alveolar macrophages.

Towards a novel continuous HME-Tableting line: Process development and control concept.

The objective of this study was to develop a novel closed-loop controlled continuous tablet manufacturing line, which first uses hot melt extrusion (HME) to produce pellets based on API and a polymer matrix. Such systems can be used to make complex pharmaceutical formulations, e.g., amorphous solid dispersions of poorly soluble APIs. The pellets are then fed to a direct compaction (DC) line blended with an external phase and tableted continuously. Fully-automated processing requires advanced control strategies, e.g., for reacting to raw material variations and process events. While many tools have been proposed for in-line process monitoring and real-time data acquisition, establishing real-time automated feedback control based on in-process control strategies remains a challenge. Control loops were implemented to assess the quality attributes of intermediates and product and to coordinate the mass flow rate between the unit operations. Feedback control for the blend concentration, strand temperature and pellet thickness was accomplished via proportional integral derivative (PID) controllers. The tablet press hopper level was controlled using a model predictive controller. To control the mass flow rates in all unit operations, several concepts were developed, with the tablet press, the extruder or none assigned to be the master unit of the line, and compared via the simulation.

Cytotoxicity screening of emulsifiers for pulmonary application of lipid nanoparticles.

INTRODUCTION: The pulmonary route is a non-invasive administration route that receives growing attention. The challenge for formulation development of orally inhaled formulations is, however, the limited number of approved excipients. Lipid nanoparticles are desired drug delivery systems for inhalation because lipids are biocompatible. However, addition of emulsifiers to stabilize the formulation may cause toxic effects. Alveolar epithelial cells and alveolar macrophages are the main cell types that get in contact with inhaled formulations in the deep lung. The different cell types are supposed to differ in the extent of particle uptake. Kolliphor RH40, Poloxamer 188, and Tween 80 are approved for use in oral formulations and widely used in the academic field for manufacturing of lipid nanoparticles. However, little is known about their pulmonary toxicity. METHODS: Cytotoxicity of Kolliphor RH40, Poloxamer 188, and Tween 80 was studied by integration into solid lipid nanoparticles loaded with itraconazole as model drug. Cytotoxicity of the formulations was assessed in human alveolar epithelial cells and human and murine macrophages and correlated to cell uptake. RESULTS: The tested emulsifiers showed overall low cytotoxicity with less pronounced adverse effects in human cells than in murine macrophages. Cellular uptake of Poloxamer 188 containing lipid nanoparticles was decreased in macrophages, while uptake of lipid nanoparticles with the other emulsifiers was similar in epithelial cells and phagocytes. CONCLUSION: The tested emulsifiers appear suitable for use in pulmonary applications. Due to larger cell size and lower proliferation rate human cells showed lower cytotoxicity than the murine cells. Being human cells, they appear more suitable for the screening of adverse effects in human lungs.